1 00:00:04,160 --> 00:00:07,160 Speaker 1: Get in touch with technology with tech Stuff from how 2 00:00:07,240 --> 00:00:13,680 Speaker 1: stuff works dot com. Hey there, and welcome to tech Stuff. 3 00:00:13,720 --> 00:00:17,440 Speaker 1: I am your host, Jonathan Strickland. I'm a senior writer 4 00:00:17,640 --> 00:00:21,160 Speaker 1: with how stuff Works dot com, where we attempt to 5 00:00:21,280 --> 00:00:26,599 Speaker 1: demystify the universe for your education and entertainment. My specialty 6 00:00:27,040 --> 00:00:32,080 Speaker 1: happens to be technology despite my degree in medieval and 7 00:00:32,159 --> 00:00:35,680 Speaker 1: Renaissance English literature. So we're gonna talk about some pretty 8 00:00:35,720 --> 00:00:38,280 Speaker 1: high tech stuff today. Actually, I'm gonna look at a 9 00:00:38,320 --> 00:00:40,840 Speaker 1: topic that we first addressed way back in two thousand 10 00:00:40,880 --> 00:00:44,199 Speaker 1: and eleven with the episode how Lasers Work. That's when 11 00:00:44,240 --> 00:00:47,840 Speaker 1: Chris Pallette, my original co host, and I sat down 12 00:00:48,159 --> 00:00:49,880 Speaker 1: and we talked about a little bit of the history 13 00:00:49,920 --> 00:00:53,320 Speaker 1: of lasers and how they actually operate. But I thought 14 00:00:53,440 --> 00:00:56,160 Speaker 1: it would be better to revisit this, explain it again, 15 00:00:56,320 --> 00:00:59,560 Speaker 1: kind of take a different approach to it. Um. So, 16 00:00:59,800 --> 00:01:04,600 Speaker 1: lasers are awesome and they can do tons of different stuff. Right. 17 00:01:04,640 --> 00:01:07,360 Speaker 1: We can do everything from having a little laser pointer 18 00:01:07,440 --> 00:01:11,680 Speaker 1: to amuse ourselves and our pets, to having a laser 19 00:01:11,720 --> 00:01:15,560 Speaker 1: element inside optical drive so that we can read information 20 00:01:15,600 --> 00:01:19,560 Speaker 1: that's been stored on a disc. Two communications satellites, to 21 00:01:19,720 --> 00:01:23,000 Speaker 1: propelling spacecraft to cutting steel. There's all sorts of things 22 00:01:23,040 --> 00:01:25,959 Speaker 1: we can do with lasers. Oh, we can threaten our enemies. 23 00:01:26,640 --> 00:01:28,399 Speaker 1: We can tie them up and put them on a 24 00:01:28,440 --> 00:01:32,360 Speaker 1: slab and then slowly have a laser creep upward and 25 00:01:32,400 --> 00:01:35,280 Speaker 1: then laugh maniacally as we expect Mr Bond to die. 26 00:01:35,600 --> 00:01:37,400 Speaker 1: We can do all that sort of stuff with lasers. 27 00:01:38,200 --> 00:01:40,120 Speaker 1: So we're gonna talk about what they are, what they 28 00:01:40,120 --> 00:01:42,720 Speaker 1: can do, their history, and maybe some cool trivia about 29 00:01:42,760 --> 00:01:46,960 Speaker 1: lasers as well, and laser related stuff. So let's get 30 00:01:46,959 --> 00:01:50,160 Speaker 1: to it now. First of all, what is the technical 31 00:01:50,320 --> 00:01:54,680 Speaker 1: definition of a laser? Well, laser is an acronym that 32 00:01:54,760 --> 00:01:56,800 Speaker 1: means that it's a word that's made up of the 33 00:01:56,840 --> 00:01:59,920 Speaker 1: initials of other words, right, so it stands for light 34 00:02:00,080 --> 00:02:04,520 Speaker 1: amplification by stimulated emission of radiation. But for most of 35 00:02:04,560 --> 00:02:07,760 Speaker 1: us that doesn't really clear things up. That just raises 36 00:02:07,800 --> 00:02:10,919 Speaker 1: other questions like what do they mean by stimulated emission 37 00:02:10,919 --> 00:02:14,920 Speaker 1: of radiation? And how do you amplify light? So I'm 38 00:02:14,960 --> 00:02:17,400 Speaker 1: gonna go in talk about all of that kind of 39 00:02:17,400 --> 00:02:19,640 Speaker 1: stuff because it's really fascinating and involves a lot of 40 00:02:19,680 --> 00:02:23,040 Speaker 1: science and technology, two things I love to talk about. 41 00:02:23,560 --> 00:02:29,000 Speaker 1: The third thing, obviously being Chaucer's Canterbury tails one that 42 00:02:29,040 --> 00:02:31,000 Speaker 1: applicated with the shoulder at SUTA, but that does not 43 00:02:31,120 --> 00:02:34,959 Speaker 1: really fit with lasers. They didn't have the lasers tail, 44 00:02:35,200 --> 00:02:38,079 Speaker 1: so we're gonna skip Canterbury Tails for this episode. Now, 45 00:02:38,120 --> 00:02:40,640 Speaker 1: a laser is a device that produces a very narrow 46 00:02:40,760 --> 00:02:44,960 Speaker 1: beam of light, and these beams are monochromatic. That means 47 00:02:44,960 --> 00:02:47,840 Speaker 1: they are single colors see single wavelength. That's a very 48 00:02:47,880 --> 00:02:51,280 Speaker 1: specific wavelength of light for each laser and us a 49 00:02:51,360 --> 00:02:56,400 Speaker 1: specific color. So we perceive different wavelengths of light as 50 00:02:56,440 --> 00:02:58,320 Speaker 1: different colors of light. So if you think of your 51 00:02:58,360 --> 00:03:04,200 Speaker 1: roy g BIV, that is actually a a spectrum literally 52 00:03:04,200 --> 00:03:07,120 Speaker 1: a spectrum of colors. That's also a spectrum of wavelengths, 53 00:03:07,160 --> 00:03:10,680 Speaker 1: with red being the longest wavelength and violet being the 54 00:03:10,720 --> 00:03:16,760 Speaker 1: shortest wavelength in the visible spectrum. Uh, the wavelength of 55 00:03:16,840 --> 00:03:21,080 Speaker 1: light depends entirely on the amount of energy electrons release 56 00:03:21,280 --> 00:03:26,280 Speaker 1: within the laser itself. So electrons release energy and in 57 00:03:26,320 --> 00:03:29,680 Speaker 1: the form of photons or light particles, and the color 58 00:03:29,720 --> 00:03:32,560 Speaker 1: of laser you get depends upon the amount of energy 59 00:03:32,600 --> 00:03:35,360 Speaker 1: those electrons are releasing, and the amount of energy they 60 00:03:35,360 --> 00:03:37,960 Speaker 1: release is dependent upon the type of atoms that they 61 00:03:37,960 --> 00:03:40,920 Speaker 1: are connected to, because it all has to do with 62 00:03:41,360 --> 00:03:45,200 Speaker 1: orbits of electrons around nuclei. More on that in a second. 63 00:03:45,480 --> 00:03:48,800 Speaker 1: So the light is also coherent. Now, that does not 64 00:03:48,960 --> 00:03:51,400 Speaker 1: mean it is able to hold a conversation and make 65 00:03:51,640 --> 00:03:55,480 Speaker 1: salient points. It's not that kind of coherent. It means 66 00:03:55,880 --> 00:04:00,320 Speaker 1: that the light is made up of organized photons. Organized 67 00:04:00,360 --> 00:04:03,360 Speaker 1: botons in this case means that they're all traveling the 68 00:04:03,440 --> 00:04:06,440 Speaker 1: same pattern of wavelength that are all in the same 69 00:04:06,600 --> 00:04:09,840 Speaker 1: page as it were. If you look at wavelength, if 70 00:04:09,840 --> 00:04:12,680 Speaker 1: you were to draw a series of waves, they would 71 00:04:12,720 --> 00:04:15,560 Speaker 1: all be lined up exactly, so all the crests and 72 00:04:15,600 --> 00:04:18,320 Speaker 1: the troughs would be lined up along the same points. 73 00:04:18,360 --> 00:04:22,400 Speaker 1: At any point along the wavelength, they would match entirely. 74 00:04:22,839 --> 00:04:26,039 Speaker 1: So that that is what we mean by coherent. It's 75 00:04:26,040 --> 00:04:29,760 Speaker 1: what helps keep the light organized and moving in that 76 00:04:30,040 --> 00:04:33,200 Speaker 1: specific direction you wanted to. And the light is also directional. 77 00:04:33,320 --> 00:04:36,280 Speaker 1: That means the beam is tight and concentrated and remains 78 00:04:36,320 --> 00:04:39,960 Speaker 1: so over great distances. You don't get a lot of 79 00:04:40,480 --> 00:04:45,520 Speaker 1: uh light diverging from that that pathway, and some lasers 80 00:04:45,520 --> 00:04:49,880 Speaker 1: are able to project for miles and miles, like hundreds 81 00:04:49,880 --> 00:04:54,320 Speaker 1: of thousands of miles in some cases or uh without 82 00:04:54,360 --> 00:04:56,840 Speaker 1: having any kind of degradation of the beam, which is 83 00:04:56,920 --> 00:04:59,080 Speaker 1: kind of cool. I mean, it's amazingly cool. Now you 84 00:04:59,120 --> 00:05:02,760 Speaker 1: contrast that with something like a flashlight. Flashlights have a 85 00:05:02,800 --> 00:05:05,919 Speaker 1: beam that spreads out as it travels outward from its source, 86 00:05:05,960 --> 00:05:09,680 Speaker 1: it diffuses, so it's different from a laser. It doesn't 87 00:05:09,839 --> 00:05:12,880 Speaker 1: have the coherence that a laser would have. Um this 88 00:05:12,960 --> 00:05:16,000 Speaker 1: is typical of most light sources. You don't find lasers 89 00:05:16,040 --> 00:05:21,000 Speaker 1: in nature. Lasers are something that we have caused to 90 00:05:21,279 --> 00:05:24,479 Speaker 1: happen because of the natural laws. If it weren't for 91 00:05:24,480 --> 00:05:28,440 Speaker 1: the natural laws, lasers wouldn't work. Obviously, we didn't create 92 00:05:28,480 --> 00:05:33,120 Speaker 1: that out of whole cloth. But it doesn't spontaneously happen 93 00:05:33,240 --> 00:05:36,640 Speaker 1: in nature because you have to have very specific parameter 94 00:05:36,760 --> 00:05:41,039 Speaker 1: set up in order to generate a laser beam. Now, 95 00:05:41,120 --> 00:05:43,839 Speaker 1: to understand why it works the way it does, it 96 00:05:43,839 --> 00:05:46,280 Speaker 1: helps to know how light works, and a light behaves 97 00:05:46,279 --> 00:05:48,839 Speaker 1: both as a wave and a particle. But for this 98 00:05:48,920 --> 00:05:51,760 Speaker 1: bit of the explanation, we're mostly concerned with wave physics, 99 00:05:51,800 --> 00:05:54,760 Speaker 1: even though we'll be talking about photons, the basic unit 100 00:05:54,880 --> 00:05:57,240 Speaker 1: of light, the basic particle of light. A lot in 101 00:05:57,279 --> 00:06:01,479 Speaker 1: this episode. So a light source gifts off waves of light, 102 00:06:01,600 --> 00:06:05,200 Speaker 1: and different colors of light have different wavelengths. Like I said, uh, 103 00:06:05,360 --> 00:06:08,159 Speaker 1: you know, those red wavelengths are longer than the orange ones. 104 00:06:08,200 --> 00:06:11,760 Speaker 1: Infrared waves are even longer, Ultra violet are even shorter 105 00:06:11,839 --> 00:06:15,400 Speaker 1: than violet. So you've got that that different spectrum of 106 00:06:15,400 --> 00:06:19,839 Speaker 1: wavelengths there. When you get down to that violet, you're 107 00:06:19,880 --> 00:06:22,640 Speaker 1: really looking at the shortest wavelengths that we can perceive 108 00:06:22,800 --> 00:06:26,279 Speaker 1: before it just becomes invisible to us. So again, ultra violet, 109 00:06:26,360 --> 00:06:30,080 Speaker 1: we can't see that um Certain classes and dungeons and 110 00:06:30,160 --> 00:06:33,520 Speaker 1: dragons different They can see ultraviolet light, not the rest 111 00:06:33,520 --> 00:06:38,200 Speaker 1: of us. So these waves travel typically out of phase 112 00:06:38,320 --> 00:06:41,080 Speaker 1: from each other from normal light sources. So again, if 113 00:06:41,120 --> 00:06:44,640 Speaker 1: you were to chart those wavelengths, the crests and valleys 114 00:06:44,720 --> 00:06:48,760 Speaker 1: would of each individual photon wouldn't match up right, like 115 00:06:48,880 --> 00:06:52,200 Speaker 1: the crest of one might be matched with the valley 116 00:06:52,240 --> 00:06:55,680 Speaker 1: of another or somewhere else along its wavelength. They wouldn't 117 00:06:55,680 --> 00:06:59,080 Speaker 1: be moving in phase, they'd be out of phase. So 118 00:07:00,440 --> 00:07:03,719 Speaker 1: lasers all line up those light waves at the same 119 00:07:03,920 --> 00:07:06,720 Speaker 1: way so that they are in phase. And that's what 120 00:07:06,760 --> 00:07:09,920 Speaker 1: we mean when we say coherent. That the various photons 121 00:07:09,920 --> 00:07:12,640 Speaker 1: are all in phase with one another, and the way 122 00:07:12,640 --> 00:07:17,040 Speaker 1: you generate lasers makes this happen. Uh, it's kind of cool. 123 00:07:17,080 --> 00:07:20,360 Speaker 1: We'll talk about that again a little bit later. But 124 00:07:20,440 --> 00:07:24,000 Speaker 1: all the photons in the beam have unified wave fronts, 125 00:07:24,120 --> 00:07:27,560 Speaker 1: so they're all moving in exactly the same wavelength a 126 00:07:27,680 --> 00:07:31,800 Speaker 1: exactly the same time. Now, to understand how all of 127 00:07:31,840 --> 00:07:35,640 Speaker 1: this works, it takes. It takes a looking at atoms. 128 00:07:35,640 --> 00:07:38,000 Speaker 1: We have to go back to basic science. So let's 129 00:07:38,000 --> 00:07:39,640 Speaker 1: take a look at an atom. Now. Back in the 130 00:07:39,680 --> 00:07:43,960 Speaker 1: day when I was in school, atoms were depicted as 131 00:07:44,000 --> 00:07:46,320 Speaker 1: being kind of like the orbits of planets, where you 132 00:07:46,360 --> 00:07:48,440 Speaker 1: would have a nucleus in the center, kind of like 133 00:07:48,480 --> 00:07:52,440 Speaker 1: the sun, and electrons would orbit a neat little circles 134 00:07:52,480 --> 00:07:57,160 Speaker 1: around at specific distances from the nucleus. As it turns out, 135 00:07:57,480 --> 00:08:00,680 Speaker 1: things aren't quite so neat and simple. Atrons are in 136 00:08:00,720 --> 00:08:04,080 Speaker 1: an electron cloud that are around the nucleus. It is 137 00:08:04,120 --> 00:08:09,240 Speaker 1: impossible to say with complete certainty, Uh, where an electron 138 00:08:09,520 --> 00:08:11,920 Speaker 1: is at any given moment. You know, you can know 139 00:08:12,000 --> 00:08:14,600 Speaker 1: a position of an electron, but not it's direction or 140 00:08:14,720 --> 00:08:18,120 Speaker 1: vice versa with complete certainty. Heisenberg's and certainty principles is 141 00:08:18,160 --> 00:08:22,600 Speaker 1: a fun thing. But you know, when you have a 142 00:08:22,680 --> 00:08:25,760 Speaker 1: basic atom and you haven't added any energy to the atom, 143 00:08:25,840 --> 00:08:30,080 Speaker 1: it's and it's ground state energy level. That's when it's 144 00:08:30,120 --> 00:08:34,479 Speaker 1: just you know, kind of chilling. Atoms are always in motion. Uh. 145 00:08:35,080 --> 00:08:38,480 Speaker 1: You only get atoms in no motion at all at 146 00:08:38,480 --> 00:08:42,079 Speaker 1: absolute zero, when you're at zero kelvin. That is when 147 00:08:42,080 --> 00:08:46,560 Speaker 1: you have zero atomic movement. But otherwise, atoms are always 148 00:08:46,559 --> 00:08:50,120 Speaker 1: in motion, even in solid objects, they're just not moving 149 00:08:50,320 --> 00:08:53,480 Speaker 1: a lot. When you add energy to atoms, they move more. 150 00:08:53,800 --> 00:08:58,079 Speaker 1: They start to get energized. When you energize atoms enough, 151 00:08:58,160 --> 00:09:01,120 Speaker 1: you can boost them to an excited level. Now, typically 152 00:09:01,120 --> 00:09:04,440 Speaker 1: you do this by applying energy like heat, light or 153 00:09:04,480 --> 00:09:08,040 Speaker 1: electricity to the atom. Uh, Whereas if you want to 154 00:09:08,080 --> 00:09:10,199 Speaker 1: excite me, you just say, hey, they might be giants 155 00:09:10,320 --> 00:09:11,679 Speaker 1: is coming to town. You want to go see them? 156 00:09:11,720 --> 00:09:14,920 Speaker 1: And I mean like, yeah, totally. So you've got atom 157 00:09:14,960 --> 00:09:17,240 Speaker 1: which consists of that nucleus, and you've got the electron 158 00:09:17,280 --> 00:09:20,680 Speaker 1: cloud around it. When you apply energy, it causes the 159 00:09:20,720 --> 00:09:26,600 Speaker 1: electrons to move to a higher orbit around that nucleus. Again, 160 00:09:26,640 --> 00:09:28,600 Speaker 1: since we're talking about a cloud and not just a 161 00:09:28,679 --> 00:09:31,920 Speaker 1: simple orbit circle, you can think of it as meaning 162 00:09:31,920 --> 00:09:35,199 Speaker 1: the electrons move a little further away from the nucleus. 163 00:09:35,240 --> 00:09:39,160 Speaker 1: If you add enough energy, you can strip electrons away 164 00:09:39,160 --> 00:09:43,760 Speaker 1: from the atom entirely. This will create a charged UH 165 00:09:43,840 --> 00:09:48,120 Speaker 1: atom because you will now have an ion. It's gonna 166 00:09:48,160 --> 00:09:50,640 Speaker 1: have a pause a net positive charge because you're gonna 167 00:09:50,640 --> 00:09:53,640 Speaker 1: have protons there and you've pulled away some of the electrons, 168 00:09:53,640 --> 00:09:56,800 Speaker 1: so you've taken some of that balance out. UH. If 169 00:09:56,840 --> 00:09:59,480 Speaker 1: you add enough electric enough energy, I was about to 170 00:09:59,480 --> 00:10:02,440 Speaker 1: say electro steve a really energy. Electricity is one form 171 00:10:02,520 --> 00:10:04,520 Speaker 1: of energy you could add to the ADAM in order 172 00:10:04,520 --> 00:10:06,959 Speaker 1: to do this. But if you didn't add that much, 173 00:10:07,160 --> 00:10:09,720 Speaker 1: like if you had it enough to excite the electrons 174 00:10:09,760 --> 00:10:13,120 Speaker 1: but not strip them away from the nucleus. When you 175 00:10:13,200 --> 00:10:17,400 Speaker 1: remove that source of energy, the electrons will move back 176 00:10:17,440 --> 00:10:20,640 Speaker 1: down to their ground state. They do not quote unquote 177 00:10:20,760 --> 00:10:24,120 Speaker 1: want to be at that excited level. They have a 178 00:10:24,200 --> 00:10:27,360 Speaker 1: ground state that they are naturally inclined to be at. 179 00:10:28,000 --> 00:10:32,720 Speaker 1: But they've absorbed energy. So in order to move back 180 00:10:32,760 --> 00:10:37,040 Speaker 1: down to their normal energy level, they have to give 181 00:10:37,160 --> 00:10:40,160 Speaker 1: up some of the energy that they've absorbed, and they 182 00:10:40,200 --> 00:10:44,880 Speaker 1: do this through emitting a photon. That basic unit of light, 183 00:10:45,880 --> 00:10:48,800 Speaker 1: and once they emit that photon, that's what allows them 184 00:10:48,800 --> 00:10:52,440 Speaker 1: to move back to their ground energy state because they 185 00:10:52,600 --> 00:10:56,959 Speaker 1: no longer have that excess energy inside of themselves. So 186 00:10:57,520 --> 00:10:59,640 Speaker 1: you can think of it as almost being like the 187 00:10:59,679 --> 00:11:02,439 Speaker 1: elect run is too full, like it's eaten too much, 188 00:11:03,000 --> 00:11:07,120 Speaker 1: and then it has little belchy belch or something it 189 00:11:07,240 --> 00:11:11,280 Speaker 1: manages to emit some part of that energy. It is absorbed, 190 00:11:11,440 --> 00:11:13,840 Speaker 1: and now it's feeling more like its old self again, 191 00:11:14,360 --> 00:11:16,120 Speaker 1: and then you can just boost it back up again 192 00:11:16,160 --> 00:11:22,240 Speaker 1: if you want to. So photons are admitted this way 193 00:11:22,480 --> 00:11:25,800 Speaker 1: through in lasers, but that's not the only way we 194 00:11:26,280 --> 00:11:31,160 Speaker 1: generate photons like there are very specific ways of doing 195 00:11:31,200 --> 00:11:35,200 Speaker 1: this in all sorts of applications, and many of them 196 00:11:35,320 --> 00:11:39,320 Speaker 1: are pretty basic. Like your incandescent lightbulb uses the same principle. 197 00:11:39,960 --> 00:11:43,880 Speaker 1: You run an electric current through some wire a filament, 198 00:11:44,080 --> 00:11:49,600 Speaker 1: typically in a vacuum sealed tube a bulb, and running 199 00:11:49,600 --> 00:11:54,120 Speaker 1: the electric current causes the filament to heat up because 200 00:11:54,160 --> 00:11:57,520 Speaker 1: it has resistance to electrical current, so some of that 201 00:11:57,559 --> 00:12:01,480 Speaker 1: electricity gets converted over into heat. As this heats up, 202 00:12:01,520 --> 00:12:05,440 Speaker 1: it excites the atoms within that filament, and as that 203 00:12:05,679 --> 00:12:10,200 Speaker 1: energy source moves through it allows those electrons to come 204 00:12:10,200 --> 00:12:13,840 Speaker 1: back down the the atoms begin to emit photons, and 205 00:12:13,840 --> 00:12:16,720 Speaker 1: then you get this glow. In the case of light bulbs, 206 00:12:16,720 --> 00:12:19,200 Speaker 1: the glow creates the light you would have from an 207 00:12:19,200 --> 00:12:22,600 Speaker 1: incandescent bulb. You could also see the same thing with 208 00:12:22,640 --> 00:12:24,600 Speaker 1: heating elements, Like if you were to look inside a 209 00:12:24,640 --> 00:12:26,800 Speaker 1: toaster and you see that orange glow, Well, that orange 210 00:12:26,800 --> 00:12:30,480 Speaker 1: glow is coming from the heating elements that have had 211 00:12:30,480 --> 00:12:33,360 Speaker 1: their atoms excited. The electrons got boosted to a higher 212 00:12:33,480 --> 00:12:37,880 Speaker 1: energy level and then they came down and started releasing photons. 213 00:12:37,920 --> 00:12:41,199 Speaker 1: So it's not just lasers that do this, but lasers 214 00:12:41,440 --> 00:12:43,559 Speaker 1: take advantage of it in a very specific way. That's 215 00:12:43,559 --> 00:12:48,280 Speaker 1: pretty cool. Now, that's just what's going on with the 216 00:12:48,280 --> 00:12:51,120 Speaker 1: physics side of things. I haven't yet explained how this 217 00:12:51,360 --> 00:12:54,160 Speaker 1: really works with a laser. So a laser uses this 218 00:12:54,240 --> 00:12:57,080 Speaker 1: principle to create those narrow beams of light. And here's 219 00:12:57,320 --> 00:13:00,280 Speaker 1: how they do it. First, you need what is called 220 00:13:00,320 --> 00:13:04,400 Speaker 1: a lazing medium, a laser medium. This is the stuff 221 00:13:04,760 --> 00:13:07,160 Speaker 1: that you're going to use to excite. You know, you're 222 00:13:07,160 --> 00:13:09,400 Speaker 1: gonna excite the atoms in this stuff so that it 223 00:13:09,559 --> 00:13:13,040 Speaker 1: generates the wavelength of light that you want, and so 224 00:13:13,120 --> 00:13:16,000 Speaker 1: the type of stuff you use that's going to determine 225 00:13:16,000 --> 00:13:18,959 Speaker 1: the type of atoms that are present, which in turn 226 00:13:19,120 --> 00:13:22,600 Speaker 1: determines the energy levels of the electrons, which in turn 227 00:13:22,720 --> 00:13:27,160 Speaker 1: determines what color light you're gonna get through the lasing medium. 228 00:13:27,200 --> 00:13:31,959 Speaker 1: All of this is dependent upon, ultimately the source of 229 00:13:32,000 --> 00:13:36,560 Speaker 1: the lazing medium, Like what is that material? The lasing 230 00:13:36,600 --> 00:13:40,400 Speaker 1: medium acts like an amplifier, only this is for optics 231 00:13:40,520 --> 00:13:43,320 Speaker 1: rather than for acoustics. So some people call the lasing 232 00:13:43,400 --> 00:13:47,319 Speaker 1: medium the gain medium or the source of optical gain 233 00:13:47,400 --> 00:13:50,920 Speaker 1: because it's like a microphone gain setting, it is amplifying 234 00:13:50,960 --> 00:13:56,680 Speaker 1: a signal. Then this case, it's amplifying light, not amplifying sound. Uh. 235 00:13:56,720 --> 00:14:00,120 Speaker 1: The gain in this case is that stimulated mission the 236 00:14:00,160 --> 00:14:03,400 Speaker 1: photons I was talking about, and the emission is stimulated 237 00:14:03,640 --> 00:14:09,280 Speaker 1: through an interesting series of events. You start by initially 238 00:14:10,240 --> 00:14:14,200 Speaker 1: adding energy to the lasing medium, and then the photons 239 00:14:14,240 --> 00:14:18,560 Speaker 1: that emits end up stimulating other atoms inside the lasing 240 00:14:18,600 --> 00:14:21,760 Speaker 1: medium that have already been excited, and then you get 241 00:14:21,800 --> 00:14:27,200 Speaker 1: a steady stream of photons that create your laser beam. 242 00:14:27,200 --> 00:14:30,520 Speaker 1: But first you have to add energy into the system. 243 00:14:30,640 --> 00:14:33,200 Speaker 1: You do this from what is called a pump source 244 00:14:33,280 --> 00:14:38,440 Speaker 1: because you are pumping energy into the lazing medium. So basically, 245 00:14:38,480 --> 00:14:42,240 Speaker 1: you pump energy into this medium, you excite some atoms, 246 00:14:42,680 --> 00:14:47,240 Speaker 1: the those excited atoms start to emit photons. Those photons 247 00:14:47,320 --> 00:14:53,480 Speaker 1: will start to h hit other stimulated atoms and that's 248 00:14:53,480 --> 00:14:57,280 Speaker 1: where you get this um stimulated emission. So there are 249 00:14:57,360 --> 00:15:00,440 Speaker 1: lots of different types of lasing media. So, for example, 250 00:15:00,600 --> 00:15:04,080 Speaker 1: there are certain crystals that can serve as a medium. Uh, 251 00:15:04,200 --> 00:15:10,640 Speaker 1: the earliest lasers were ruby lasers, so you would get 252 00:15:10,640 --> 00:15:13,600 Speaker 1: a ruby crystal and that would be your lasing medium. 253 00:15:14,120 --> 00:15:17,840 Speaker 1: You would usually in introduce some impurities. It's called doping. 254 00:15:18,360 --> 00:15:21,400 Speaker 1: You add some impurities to the material in order to 255 00:15:21,960 --> 00:15:24,800 Speaker 1: make this a more efficient lasing medium. Usually it's some 256 00:15:24,920 --> 00:15:29,200 Speaker 1: ions of some sort um and that helps when you're 257 00:15:29,240 --> 00:15:33,560 Speaker 1: actually getting to the part of generating a laser. Those 258 00:15:33,640 --> 00:15:37,160 Speaker 1: are specifically solid state lasers, the ones that use crystals. 259 00:15:37,280 --> 00:15:41,680 Speaker 1: You're using a solid lasing medium. But there are other 260 00:15:41,680 --> 00:15:44,400 Speaker 1: ones as well. There's some that use glasses, some that 261 00:15:44,560 --> 00:15:48,560 Speaker 1: use gases, including reactive gases like chlorine and florine. Those 262 00:15:48,600 --> 00:15:53,200 Speaker 1: are specific types of gas lasers that are called xemer lasers. 263 00:15:53,600 --> 00:15:57,680 Speaker 1: You have semiconductor lasers, which produce, in the grand scheme 264 00:15:57,720 --> 00:16:00,560 Speaker 1: of things, fairly weak lasers. But they also are fairly 265 00:16:00,600 --> 00:16:03,600 Speaker 1: inexpensive to produce, and those are the ones that we 266 00:16:03,760 --> 00:16:07,560 Speaker 1: use in things like CD players, DVD players, Blu ray players, 267 00:16:07,560 --> 00:16:10,240 Speaker 1: that kind of stuff. They tend to be semiconductor lasers. 268 00:16:10,240 --> 00:16:13,360 Speaker 1: They're easy to mass produce, they're less expensive, and they 269 00:16:13,360 --> 00:16:15,880 Speaker 1: aren't so powerful as to cause problems. You don't need 270 00:16:15,960 --> 00:16:19,040 Speaker 1: a CD player laser that could burn a hole through 271 00:16:19,600 --> 00:16:23,160 Speaker 1: the surface of the Earth. That would be ridiculous. You 272 00:16:23,200 --> 00:16:28,520 Speaker 1: can also get liquid medium lasers. These are liquids that 273 00:16:28,560 --> 00:16:33,280 Speaker 1: have various organic dyes special organic dyes d y e 274 00:16:33,680 --> 00:16:39,200 Speaker 1: s that will allow for this stimulated emission of light 275 00:16:39,480 --> 00:16:43,520 Speaker 1: amplified light. Now, the pump is some sort of energy 276 00:16:43,560 --> 00:16:45,520 Speaker 1: transfer that you use to excite those atoms in the 277 00:16:45,560 --> 00:16:49,160 Speaker 1: first place, so that they'll emit those initial photons when 278 00:16:49,280 --> 00:16:54,680 Speaker 1: the electrons calm the heck down. Laser pumps are some 279 00:16:54,760 --> 00:16:59,160 Speaker 1: form of external source of energy. Typically they supply energy 280 00:16:59,160 --> 00:17:02,120 Speaker 1: in the form of either electricity or light, but there 281 00:17:02,160 --> 00:17:06,840 Speaker 1: are other means of pumping a lazing medium with energy 282 00:17:06,920 --> 00:17:11,800 Speaker 1: to create lasers. Light and electricity are the two most 283 00:17:11,960 --> 00:17:14,680 Speaker 1: common ones, but they are not the only kinds. There's 284 00:17:14,720 --> 00:17:18,240 Speaker 1: some that use chemical reactions. There's some that even use 285 00:17:18,480 --> 00:17:21,320 Speaker 1: nuclear reactions, which I think is taking in a little 286 00:17:21,359 --> 00:17:24,800 Speaker 1: far if you're asking me, uh, that's me mostly being 287 00:17:24,800 --> 00:17:28,480 Speaker 1: tongue in cheek. But again, most of the lasers that 288 00:17:28,760 --> 00:17:32,240 Speaker 1: we would encounter throughout our day, those are generated either 289 00:17:32,400 --> 00:17:37,080 Speaker 1: through light or through electricity stimulating the lasing medium. So, 290 00:17:38,960 --> 00:17:41,920 Speaker 1: for example, most most early lasers were using some form 291 00:17:42,000 --> 00:17:47,600 Speaker 1: of arc or flash lamp to stimulate that initial reaction 292 00:17:48,080 --> 00:17:52,800 Speaker 1: within the atoms of lazing medium, like a crystal rod. Uh. So, 293 00:17:52,840 --> 00:17:55,080 Speaker 1: you got your crystal rod with a few impurities in 294 00:17:55,119 --> 00:17:57,000 Speaker 1: it that you have specifically placed in there. You have 295 00:17:57,119 --> 00:18:02,719 Speaker 1: doped this crystal rod. You would wrap a light source 296 00:18:02,840 --> 00:18:08,800 Speaker 1: around this thing, usually within some sort of mirrored chamber, 297 00:18:09,640 --> 00:18:15,119 Speaker 1: and you would flash light impulses against the lasing medium, 298 00:18:15,200 --> 00:18:19,120 Speaker 1: and this would actually excite atoms within the medium, which 299 00:18:19,119 --> 00:18:23,479 Speaker 1: would then give off photons. Now, if there were no 300 00:18:23,680 --> 00:18:28,359 Speaker 1: way for you to keep this reaction going, it would 301 00:18:28,359 --> 00:18:31,560 Speaker 1: be such a small emission of photons that you probably 302 00:18:31,600 --> 00:18:33,800 Speaker 1: wouldn't even be able to tell. You wouldn't even it 303 00:18:33,800 --> 00:18:38,439 Speaker 1: wouldn't be visible to you. However, by tricking it you 304 00:18:38,480 --> 00:18:41,479 Speaker 1: can totally make it visible. So you typically would use 305 00:18:41,520 --> 00:18:45,040 Speaker 1: these mirrors to reflect light back into the lasing medium. 306 00:18:45,080 --> 00:18:50,119 Speaker 1: That includes photons that were admitted during that initial flash, 307 00:18:50,200 --> 00:18:52,640 Speaker 1: and that's what allows you to create a cascade effect 308 00:18:53,240 --> 00:18:57,840 Speaker 1: and create a laser. Generally speaking, you would probably use 309 00:18:57,920 --> 00:19:01,600 Speaker 1: mirrors that would allow the election of any wavelengths of 310 00:19:01,720 --> 00:19:05,160 Speaker 1: light that were shorter than the laser's wavelength would be, 311 00:19:05,640 --> 00:19:10,760 Speaker 1: and allow the transference of light that is longer, wavelengths 312 00:19:10,800 --> 00:19:14,439 Speaker 1: longer than the laser's wavelength that you want. The reason 313 00:19:14,480 --> 00:19:16,760 Speaker 1: for that is that if you were to trap all 314 00:19:16,800 --> 00:19:20,119 Speaker 1: the light within the chamber, you could cause things to 315 00:19:20,160 --> 00:19:23,640 Speaker 1: heat up and create what's called thermal lensing. The actual 316 00:19:23,720 --> 00:19:27,280 Speaker 1: change in temperature would create a lens effect that would 317 00:19:27,880 --> 00:19:31,040 Speaker 1: end up affecting the ability of a laser to be 318 00:19:31,280 --> 00:19:34,240 Speaker 1: directional and coherent. And obviously, if that's your intent, you 319 00:19:34,240 --> 00:19:37,919 Speaker 1: don't want that to happen. So, yeah, Thermal lensing occurs 320 00:19:37,920 --> 00:19:40,080 Speaker 1: when a sample absorbs energy from a laser beam, it 321 00:19:40,160 --> 00:19:43,800 Speaker 1: heats up, it creates this refractive lens that causes beam divergence. 322 00:19:44,560 --> 00:19:46,960 Speaker 1: That's not what you want with a laser. Typically, I mean, 323 00:19:47,000 --> 00:19:50,359 Speaker 1: you might want to design a system that creates that 324 00:19:50,480 --> 00:19:53,680 Speaker 1: splits a beam, but that's different from beam divergence. You 325 00:19:54,040 --> 00:19:57,480 Speaker 1: want that beam to be nice and tight. Uh, typically 326 00:19:57,720 --> 00:20:03,240 Speaker 1: or your your average laser applications. So let's let's imagine 327 00:20:03,240 --> 00:20:06,719 Speaker 1: that we're building a laser and we start with a 328 00:20:06,840 --> 00:20:10,760 Speaker 1: rod made out of ruby. I was gonna say that 329 00:20:10,800 --> 00:20:13,719 Speaker 1: you could have a ruby rod, but we all know 330 00:20:13,840 --> 00:20:16,440 Speaker 1: that he is busy with Corbin Dallas trying to save 331 00:20:16,480 --> 00:20:19,840 Speaker 1: the universe. Shout out to any of you guys out 332 00:20:19,880 --> 00:20:24,360 Speaker 1: there who understand what that reference means. So you've got 333 00:20:24,480 --> 00:20:27,679 Speaker 1: ruby rod, and you've got a flash tube that is 334 00:20:28,400 --> 00:20:31,719 Speaker 1: probably wrapped around the ruby rod, but at least as 335 00:20:32,000 --> 00:20:35,239 Speaker 1: shining can shine on the ruby rod, and you can 336 00:20:35,320 --> 00:20:38,840 Speaker 1: use the flash tube out of like a camera. In fact, 337 00:20:38,920 --> 00:20:44,439 Speaker 1: the earliest lasers were using camera flashbulbs as the source 338 00:20:44,480 --> 00:20:46,960 Speaker 1: of light to start this reaction. It's not like it's 339 00:20:47,000 --> 00:20:51,160 Speaker 1: something super high tech. It's actually pretty cool. And you've 340 00:20:51,200 --> 00:20:55,199 Speaker 1: got a mirrored chamber that surrounds the whole thing on 341 00:20:55,320 --> 00:20:58,199 Speaker 1: the on either end of the rod. So think of 342 00:20:58,240 --> 00:21:01,720 Speaker 1: the rod is like a cylinder. You have put a 343 00:21:01,840 --> 00:21:05,960 Speaker 1: silvered mirror on either end. One side is a pure 344 00:21:06,040 --> 00:21:09,560 Speaker 1: silvered mirror, so it just reflects light. The other one 345 00:21:09,680 --> 00:21:13,119 Speaker 1: is a partially silvered mirror, meaning that it can allow 346 00:21:13,240 --> 00:21:16,480 Speaker 1: some light to pass through. Specifically, you want to design 347 00:21:16,480 --> 00:21:19,600 Speaker 1: it so it allows the wavelength of the laser light 348 00:21:19,640 --> 00:21:22,159 Speaker 1: to pass through, but doesn't allow any other light to 349 00:21:22,160 --> 00:21:27,120 Speaker 1: pass through. Uh, you turn on the flash tube. This 350 00:21:27,359 --> 00:21:30,359 Speaker 1: shines bright light onto the rod, which causes some of 351 00:21:30,359 --> 00:21:33,960 Speaker 1: the atoms in the rod to excite. Then as those 352 00:21:34,000 --> 00:21:37,439 Speaker 1: electrons move back down from their excited stage back to 353 00:21:37,520 --> 00:21:42,000 Speaker 1: the ground level stage, they release photons, and with enough 354 00:21:42,119 --> 00:21:44,840 Speaker 1: energy pumped into the medium, you end up with a 355 00:21:44,960 --> 00:21:48,840 Speaker 1: larger population of atoms that are in an excited state 356 00:21:49,400 --> 00:21:52,320 Speaker 1: then there are atoms in the ground state. When you 357 00:21:52,359 --> 00:21:57,200 Speaker 1: reach that point, it is called a population inversion because 358 00:21:57,240 --> 00:22:01,399 Speaker 1: you've inverted the relationship between a sited atoms and ground 359 00:22:01,480 --> 00:22:04,919 Speaker 1: state atoms. Typically, you would have more ground state atoms 360 00:22:04,920 --> 00:22:07,880 Speaker 1: than excited ones. Once you're able to flip that balance, 361 00:22:07,920 --> 00:22:10,840 Speaker 1: you can create this cascading effect that I've been talking about. 362 00:22:11,400 --> 00:22:14,959 Speaker 1: So you've got more excited atoms than you have ground 363 00:22:15,400 --> 00:22:19,640 Speaker 1: energy level atoms inside of this lasing medium. At that point, 364 00:22:19,720 --> 00:22:24,200 Speaker 1: they started giving off photons, and this is pretty cool. 365 00:22:24,320 --> 00:22:29,560 Speaker 1: What happens next is photons from some of those first 366 00:22:30,920 --> 00:22:34,160 Speaker 1: UH atoms that had been excited and they were calming down. 367 00:22:34,200 --> 00:22:36,920 Speaker 1: If you like, they'll go out and they'll hit other 368 00:22:37,080 --> 00:22:40,760 Speaker 1: excited atoms. So these are atoms that I've already had 369 00:22:40,760 --> 00:22:47,040 Speaker 1: their energy levels boosted by that flashbulb. The photon from 370 00:22:47,359 --> 00:22:51,600 Speaker 1: the first atom, the one that excited then calmed down, 371 00:22:52,520 --> 00:22:55,919 Speaker 1: has just the right amount of energy to cause the 372 00:22:56,040 --> 00:22:59,000 Speaker 1: electron in an excited atom to come back down to 373 00:22:59,080 --> 00:23:03,239 Speaker 1: its ground state and release a another photon. So what 374 00:23:03,240 --> 00:23:06,959 Speaker 1: happens is the atom that it it connects with will 375 00:23:07,000 --> 00:23:10,480 Speaker 1: absorb the photon, then it will emit the photon and 376 00:23:10,560 --> 00:23:14,280 Speaker 1: emit a second photon as its own electron comes down 377 00:23:14,720 --> 00:23:18,520 Speaker 1: an energy level. So you get two photons emitted, the 378 00:23:18,600 --> 00:23:23,200 Speaker 1: initial one that you shot the atom with and then 379 00:23:23,280 --> 00:23:26,399 Speaker 1: the one that that atom produced itself. So this is 380 00:23:26,400 --> 00:23:30,800 Speaker 1: what it's called light amplification. Right, you have amplified the light. 381 00:23:30,960 --> 00:23:34,280 Speaker 1: You started with one photon. Now you have two photons 382 00:23:34,359 --> 00:23:39,080 Speaker 1: and they're moving in phase with one another because well 383 00:23:39,119 --> 00:23:40,879 Speaker 1: because of quantum physics, but I don't want to get 384 00:23:40,920 --> 00:23:45,960 Speaker 1: into that too much. So you get this light amplification 385 00:23:46,200 --> 00:23:51,000 Speaker 1: through that process. Now that you have the light amplification. 386 00:23:51,280 --> 00:23:54,119 Speaker 1: You might as well say, like, well, what are we 387 00:23:54,160 --> 00:23:57,320 Speaker 1: calling this? This whole process where a photon can cause 388 00:23:57,480 --> 00:24:01,000 Speaker 1: another atom to admit a photon, that's the stimulated emission. 389 00:24:01,600 --> 00:24:03,919 Speaker 1: You might think stimulated emission was when you turned on 390 00:24:03,960 --> 00:24:07,600 Speaker 1: the flash bulb. That's not technically correct. The stimulated emission 391 00:24:07,640 --> 00:24:12,360 Speaker 1: part technically comes from these initial atoms that release photons, 392 00:24:12,480 --> 00:24:16,640 Speaker 1: and those cause this chain reaction in the lasing medium. 393 00:24:16,680 --> 00:24:19,200 Speaker 1: So this can happen over and over and over again. Right, 394 00:24:19,240 --> 00:24:22,720 Speaker 1: You're not really the atoms aren't losing any matter in this. 395 00:24:22,800 --> 00:24:25,760 Speaker 1: It's just a process of electrons being boosted up to 396 00:24:25,800 --> 00:24:28,240 Speaker 1: an energy level and then coming back down again, so 397 00:24:28,280 --> 00:24:32,920 Speaker 1: they're releasing energy. They're not losing anything in this. It's 398 00:24:33,000 --> 00:24:37,399 Speaker 1: just a transfer of energy and really a transformation of 399 00:24:37,440 --> 00:24:42,440 Speaker 1: it from one form of light to another. So it's 400 00:24:42,440 --> 00:24:46,360 Speaker 1: fascinating to me that this is something that not only works, 401 00:24:46,400 --> 00:24:49,840 Speaker 1: but that people were able to figure out would work um. 402 00:24:49,880 --> 00:24:55,439 Speaker 1: It's it's so far into quantum physics and optics and 403 00:24:55,480 --> 00:25:00,360 Speaker 1: photonics that I am amazed that people figured us out. 404 00:25:00,400 --> 00:25:02,919 Speaker 1: In fact, they figured it out way back at the 405 00:25:02,960 --> 00:25:05,840 Speaker 1: beginning of the twentieth century. It would take the middle 406 00:25:05,960 --> 00:25:08,600 Speaker 1: of the twentieth century before anyone built a working laser, 407 00:25:09,520 --> 00:25:13,760 Speaker 1: but they figured out the physics of it decades ahead 408 00:25:13,760 --> 00:25:16,280 Speaker 1: of time, and that still blows my mind to this day. 409 00:25:16,440 --> 00:25:18,920 Speaker 1: Then again, I'm also the guy who can't figure out 410 00:25:18,920 --> 00:25:23,840 Speaker 1: which remote control controls the TV versus the audio system. 411 00:25:23,880 --> 00:25:29,960 Speaker 1: So what do I know. You get this series of 412 00:25:29,960 --> 00:25:34,439 Speaker 1: photons being omitted that are all in phase with one another, 413 00:25:35,080 --> 00:25:38,080 Speaker 1: and they bounce back and forth between these two mirrored 414 00:25:38,280 --> 00:25:42,439 Speaker 1: ends of this ruby rod. But some of them can 415 00:25:42,480 --> 00:25:46,719 Speaker 1: pass through the half silvered or partially silvered end because 416 00:25:47,080 --> 00:25:50,119 Speaker 1: that it allows for that, and this is the source 417 00:25:50,119 --> 00:25:52,720 Speaker 1: of the laser beam. The photons that get out through 418 00:25:52,720 --> 00:25:55,560 Speaker 1: that end become the laser beam, and it's just a 419 00:25:55,640 --> 00:25:59,560 Speaker 1: steady beam of light that will continue to fire as 420 00:25:59,600 --> 00:26:03,199 Speaker 1: long as this reaction is allowed to continue. If you 421 00:26:03,280 --> 00:26:07,040 Speaker 1: remove that source of energy, the pump energy that is 422 00:26:07,160 --> 00:26:10,880 Speaker 1: allowing this to happen in the first place, it will stop, 423 00:26:11,320 --> 00:26:16,280 Speaker 1: right it will. The reaction is not sustaining. It can't 424 00:26:16,320 --> 00:26:18,080 Speaker 1: just keep on going, and you have to have that 425 00:26:18,160 --> 00:26:23,560 Speaker 1: external source of energy to maintain it throughout the whole process, 426 00:26:23,600 --> 00:26:30,120 Speaker 1: otherwise it just goes dark. So that's basically how your 427 00:26:30,240 --> 00:26:34,119 Speaker 1: standard laser works. Now, if you're using that ruby based 428 00:26:34,200 --> 00:26:37,639 Speaker 1: laser I was talking about, the wavelength of the laser 429 00:26:37,760 --> 00:26:41,920 Speaker 1: light could be measured at six hundred and ninety four nanometers. 430 00:26:41,920 --> 00:26:48,040 Speaker 1: That's how long a wavelength of ruby laser is. Six 431 00:26:49,200 --> 00:26:52,879 Speaker 1: which is incredibly tiny. The visible spectrum of light is 432 00:26:52,960 --> 00:26:56,679 Speaker 1: between four nimes, which would be the violet side, up 433 00:26:56,680 --> 00:26:59,439 Speaker 1: to seven nimes, which is the red side. So this 434 00:26:59,600 --> 00:27:02,639 Speaker 1: ruby one is right up there at the top level 435 00:27:02,800 --> 00:27:06,480 Speaker 1: of what we can see as human beings. Now, you 436 00:27:06,480 --> 00:27:09,360 Speaker 1: can also have infrared or ultra violet lasers. Obviously those 437 00:27:09,359 --> 00:27:12,120 Speaker 1: would be invisible to us, but they would still exist 438 00:27:12,200 --> 00:27:14,960 Speaker 1: and you can still do some pretty cool stuff with it. 439 00:27:15,000 --> 00:27:18,480 Speaker 1: In fact, uh, infrared lasers are often used to cut 440 00:27:18,920 --> 00:27:22,720 Speaker 1: steel for example. Much pretty serious stuff when you think 441 00:27:22,760 --> 00:27:26,199 Speaker 1: about it. But we'll talk about that more in a 442 00:27:26,240 --> 00:27:30,240 Speaker 1: little bit Before we get into more about Pepe lasers. 443 00:27:30,880 --> 00:27:40,400 Speaker 1: Let's take a quick break to thank our sponsor. Now. 444 00:27:40,480 --> 00:27:44,280 Speaker 1: According to the company Wicked Lasers, which makes a range 445 00:27:44,280 --> 00:27:49,560 Speaker 1: of laser products, including ones that are capable of actually 446 00:27:49,680 --> 00:27:53,280 Speaker 1: burning stuff if you use them, uh, they say that 447 00:27:53,320 --> 00:27:57,480 Speaker 1: the wavelength of five five nanometers is ideal for brightness 448 00:27:57,520 --> 00:27:59,920 Speaker 1: compared to other colors that are produced at that same 449 00:28:00,080 --> 00:28:03,199 Speaker 1: amount of power. So lasers have a couple of different 450 00:28:03,280 --> 00:28:07,879 Speaker 1: elements to them. There's the wavelength of the laser itself, 451 00:28:08,680 --> 00:28:11,240 Speaker 1: and then there's the amount of power that you are 452 00:28:11,680 --> 00:28:16,600 Speaker 1: able to generate. You measure laser power in in milliwatts 453 00:28:16,920 --> 00:28:19,960 Speaker 1: typically for the ones that we use uh day to 454 00:28:20,080 --> 00:28:23,280 Speaker 1: day as consumers. They can go higher than milliwatts, but 455 00:28:24,480 --> 00:28:27,560 Speaker 1: typically the ones we consumers use are in the milliwatt 456 00:28:27,640 --> 00:28:32,159 Speaker 1: lage range rather uh. But you you would measure them 457 00:28:32,160 --> 00:28:34,880 Speaker 1: in watts the same way you would with light bulbs. 458 00:28:34,880 --> 00:28:39,360 Speaker 1: But a ten what laser or a fifty watt laser 459 00:28:39,920 --> 00:28:43,760 Speaker 1: would be much more much brighter than a fifty watt 460 00:28:43,800 --> 00:28:46,960 Speaker 1: light bulb, because remember a fifty what light bulb is 461 00:28:46,960 --> 00:28:50,920 Speaker 1: giving out fifty watts of light, but it's it's emitting 462 00:28:50,960 --> 00:28:55,400 Speaker 1: that in practically all directions, whereas a laser has it 463 00:28:55,680 --> 00:28:59,840 Speaker 1: very much concentrated in a coherent beam. So a fifty 464 00:29:00,200 --> 00:29:03,640 Speaker 1: laser would be incredibly bright compared to a fifty watt 465 00:29:03,720 --> 00:29:07,200 Speaker 1: light bulb. We're mostly talking about milliwatts. So if you 466 00:29:07,280 --> 00:29:13,880 Speaker 1: have a a certain laser pointer of let's say let's 467 00:29:13,920 --> 00:29:17,600 Speaker 1: just say twenty milliwatts. I mean, it's incredibly small, but 468 00:29:17,640 --> 00:29:20,280 Speaker 1: this is just for the purposes of an example, twenty 469 00:29:20,320 --> 00:29:25,200 Speaker 1: milliwatt laser pointer, and it's green, which is closer to 470 00:29:25,240 --> 00:29:29,160 Speaker 1: that five fifty five nanometers in wavelength, and then you've 471 00:29:29,160 --> 00:29:31,959 Speaker 1: got another one that's read. The green one's gonna appear 472 00:29:32,000 --> 00:29:34,760 Speaker 1: brighter than the red one, even if they're both emitting 473 00:29:34,840 --> 00:29:41,440 Speaker 1: the same wattage of laser light, because our visual acuity 474 00:29:41,560 --> 00:29:44,960 Speaker 1: is closer to that five fifty five nanometer wavelength range. 475 00:29:45,480 --> 00:29:49,239 Speaker 1: So violet and blue lasers are slightly less powerful than that, 476 00:29:50,040 --> 00:29:51,480 Speaker 1: but the greens are the ones that are going to 477 00:29:51,560 --> 00:29:56,880 Speaker 1: show up the best for their respective amount of power. Obviously, 478 00:29:56,920 --> 00:29:59,680 Speaker 1: you can pour more power into a laser, and in 479 00:29:59,760 --> 00:30:01,920 Speaker 1: some cases you can end up with a brighter laser 480 00:30:02,440 --> 00:30:05,160 Speaker 1: because of it, of course, depending upon whether or not 481 00:30:05,200 --> 00:30:07,480 Speaker 1: the laser is within the visible spectrum in the first place. 482 00:30:07,520 --> 00:30:10,200 Speaker 1: It doesn't matter how much power you pour into an 483 00:30:10,200 --> 00:30:12,800 Speaker 1: infrared laser. You're never gonna see it. You'll see the 484 00:30:12,840 --> 00:30:15,960 Speaker 1: results because it will burn through stuff, but you won't 485 00:30:16,000 --> 00:30:19,840 Speaker 1: see the laser itself. But yeah, it's all it's all 486 00:30:19,880 --> 00:30:22,840 Speaker 1: about those extra things as well, not just the wavelength, 487 00:30:22,840 --> 00:30:25,880 Speaker 1: but also the power. So that's really what helps determinal 488 00:30:25,960 --> 00:30:29,480 Speaker 1: laser strength is the wavelength and the amount of power 489 00:30:29,520 --> 00:30:31,640 Speaker 1: that it's putting out. Really, how much power are you 490 00:30:31,640 --> 00:30:34,880 Speaker 1: putting in and getting out of it? So if I 491 00:30:34,960 --> 00:30:38,760 Speaker 1: want to use a death laser in order to defeat 492 00:30:38,760 --> 00:30:42,600 Speaker 1: my arch nemesis who happens to be a British secret spy, 493 00:30:43,600 --> 00:30:47,200 Speaker 1: and I want to also use another laser to amuse 494 00:30:47,280 --> 00:30:50,080 Speaker 1: my cat but not turn it into kitty cat flambay, 495 00:30:50,680 --> 00:30:53,320 Speaker 1: what do I need to do to make sure about that? Well, 496 00:30:54,360 --> 00:30:58,320 Speaker 1: one is again that wavelength of light. Certain wavelengths are 497 00:30:58,400 --> 00:31:03,440 Speaker 1: absorbed more readily by a broader variety of substances than 498 00:31:03,480 --> 00:31:07,000 Speaker 1: other wavelengths. So if you pick a wavelength that is 499 00:31:07,080 --> 00:31:11,920 Speaker 1: easily absorbed by lots of different stuff, that is going 500 00:31:12,000 --> 00:31:16,280 Speaker 1: to transfer energy more readily to your target. So, as 501 00:31:16,320 --> 00:31:20,200 Speaker 1: it turns out, and for red lasers can really transfer 502 00:31:20,360 --> 00:31:22,840 Speaker 1: a lot of energy to a broad array of stuff, 503 00:31:23,600 --> 00:31:28,360 Speaker 1: including steel. That's why carbon dioxide megawatt lasers are used 504 00:31:28,400 --> 00:31:33,320 Speaker 1: to cut through stuff like sheets of steel. But other 505 00:31:33,600 --> 00:31:37,760 Speaker 1: colors are not as easily absorbed by as wide a 506 00:31:37,880 --> 00:31:40,360 Speaker 1: variety of materials, and so you would really have to 507 00:31:40,400 --> 00:31:44,160 Speaker 1: pour more energy into the laser in order to get 508 00:31:44,200 --> 00:31:47,920 Speaker 1: a beam strong enough to start cutting through stuff. So 509 00:31:48,240 --> 00:31:50,480 Speaker 1: it depends on both how much power you're putting into 510 00:31:50,480 --> 00:31:54,000 Speaker 1: the laser and the wavelength of the light. Both of 511 00:31:54,040 --> 00:31:57,720 Speaker 1: those together will determine how strong quote unquote your laser is. 512 00:31:57,960 --> 00:32:01,680 Speaker 1: Strong isn't really a meaningful term because there are different 513 00:32:01,720 --> 00:32:04,880 Speaker 1: ways of measuring laser. It's by how much light it 514 00:32:04,880 --> 00:32:08,880 Speaker 1: gives off and also how much energy does it transfer 515 00:32:09,000 --> 00:32:11,640 Speaker 1: to a target. But if you're talking about the energy 516 00:32:11,680 --> 00:32:14,240 Speaker 1: transferred to a target, those are the two things you 517 00:32:14,240 --> 00:32:17,360 Speaker 1: have to worry about. The wavelength and the amount of 518 00:32:17,480 --> 00:32:21,000 Speaker 1: power that it generates. You can use other stuff to 519 00:32:21,040 --> 00:32:23,560 Speaker 1: help with that too, like lenses. You can use lenses 520 00:32:23,600 --> 00:32:28,800 Speaker 1: to help maintain a tighter laser for further distances, but 521 00:32:29,560 --> 00:32:34,960 Speaker 1: ultimately it's power and wavelength that you're really concerned with. AH. 522 00:32:35,200 --> 00:32:38,480 Speaker 1: Lasers can be used for all sorts of things, from 523 00:32:38,520 --> 00:32:41,480 Speaker 1: optical media like DVDs, blue rays, and CD players, to 524 00:32:41,560 --> 00:32:45,640 Speaker 1: communication systems to massive industrial lasers UH that can cut 525 00:32:45,640 --> 00:32:48,040 Speaker 1: through steel like warm butter and they're really nifty. But 526 00:32:48,080 --> 00:32:50,880 Speaker 1: I thought it might be interesting to learn a little 527 00:32:50,920 --> 00:32:56,000 Speaker 1: bit more about not just how lasers work, but sort 528 00:32:56,000 --> 00:33:00,400 Speaker 1: of the the history of lasers as well, right, because 529 00:33:01,240 --> 00:33:03,680 Speaker 1: there's a ton of different stuff to to talk about. 530 00:33:03,720 --> 00:33:09,760 Speaker 1: I mean, who figured out how lasers would even be 531 00:33:09,840 --> 00:33:13,640 Speaker 1: a thing? Like where did that come from? So to 532 00:33:13,680 --> 00:33:16,600 Speaker 1: trace the history of the laser, you have to look 533 00:33:16,600 --> 00:33:19,760 Speaker 1: at the scientists whose work provided the foundation for all 534 00:33:19,760 --> 00:33:23,040 Speaker 1: the people who followed. So all the scientists and engineers 535 00:33:23,040 --> 00:33:26,480 Speaker 1: who actually started building lasers in the nineteen fifties, they 536 00:33:26,520 --> 00:33:30,280 Speaker 1: did this working off of the theoretical work of people 537 00:33:30,280 --> 00:33:33,040 Speaker 1: who came before them. So one of those people was 538 00:33:33,160 --> 00:33:37,240 Speaker 1: Max Planck. So Planck was born in eighteen fifty eight 539 00:33:37,280 --> 00:33:40,080 Speaker 1: in Germany, and his father was a law professor. And 540 00:33:40,120 --> 00:33:43,240 Speaker 1: when he was a kid, he was really good at 541 00:33:43,280 --> 00:33:45,880 Speaker 1: study aims stuff. He was really interested in tons of 542 00:33:45,880 --> 00:33:48,280 Speaker 1: different things. He was he was a bit of a pollymath, 543 00:33:49,040 --> 00:33:53,840 Speaker 1: really intelligent and very and very accomplished in several fields, 544 00:33:53,920 --> 00:33:57,120 Speaker 1: uh including music. And in fact, when he turned seventeen, 545 00:33:57,120 --> 00:33:59,000 Speaker 1: he had to make the tough decision what was he 546 00:33:59,040 --> 00:34:01,160 Speaker 1: going to pursue as a care ere Was he going 547 00:34:01,240 --> 00:34:04,840 Speaker 1: to continue to study science or was he going to 548 00:34:04,920 --> 00:34:09,560 Speaker 1: become a musician. And somewhere there's an alternate universe where 549 00:34:09,560 --> 00:34:12,400 Speaker 1: Plank decided to become a musician instead of a physicist, 550 00:34:13,120 --> 00:34:16,960 Speaker 1: and in that alternate universe we had totally different types 551 00:34:17,000 --> 00:34:21,439 Speaker 1: of piano music that Plank would have written. It would 552 00:34:21,480 --> 00:34:25,080 Speaker 1: have been amazing. But I think we're pretty thankful for 553 00:34:25,239 --> 00:34:28,279 Speaker 1: his contributions to science. So ultimately, if we were to 554 00:34:28,320 --> 00:34:30,600 Speaker 1: measure us versus them, I think we get the better 555 00:34:30,680 --> 00:34:33,319 Speaker 1: end of the deal. But still, it's really interesting to 556 00:34:33,360 --> 00:34:35,719 Speaker 1: think that he could have become a musician instead of 557 00:34:35,719 --> 00:34:40,960 Speaker 1: a physicist. And he's sort of the father of quantum physics, 558 00:34:41,360 --> 00:34:44,920 Speaker 1: so if he had not gone into study physics, it 559 00:34:45,040 --> 00:34:49,560 Speaker 1: might have delayed our study of quantum physics as a 560 00:34:49,600 --> 00:34:54,480 Speaker 1: discipline by at least a decade, potentially more because his 561 00:34:54,560 --> 00:34:58,680 Speaker 1: work would go on to inspire lots of other heavy thinkers, 562 00:34:58,800 --> 00:35:05,960 Speaker 1: including Mr Albert Einstein. So Plank earned his doctorate the 563 00:35:06,080 --> 00:35:11,560 Speaker 1: same year as Einstein's birth, so Planka's predecessor to Albert Einstein, obviously, 564 00:35:11,880 --> 00:35:15,360 Speaker 1: and Einstein would take inspiration from several of plans ideas, 565 00:35:15,360 --> 00:35:18,479 Speaker 1: and one of those was plucks idea that energy could 566 00:35:18,520 --> 00:35:23,440 Speaker 1: only be emitted and absorbed in discrete amounts. So if 567 00:35:23,480 --> 00:35:27,520 Speaker 1: you think about it, it's almost more like digital versus analog. 568 00:35:28,080 --> 00:35:31,200 Speaker 1: If you've listened to me talk about digital audio, you 569 00:35:31,280 --> 00:35:34,440 Speaker 1: know how digital audio is made up of tiny little 570 00:35:34,560 --> 00:35:42,960 Speaker 1: steps of pitch and volume, whereas analog is a continuous wave. Right, 571 00:35:43,080 --> 00:35:47,600 Speaker 1: digital audio is a bunch of discrete little moments in time, 572 00:35:48,280 --> 00:35:50,480 Speaker 1: and the number of those moments in time that's your 573 00:35:50,480 --> 00:35:53,400 Speaker 1: sample rate. The more the higher your sample rate is, 574 00:35:53,440 --> 00:35:57,239 Speaker 1: the closer this looks to be a continuous line. But 575 00:35:57,280 --> 00:36:01,320 Speaker 1: it's not really a continuous line. It's tiny little steps 576 00:36:01,920 --> 00:36:07,000 Speaker 1: in pitch and volume. Well, Planck's point was that energy 577 00:36:07,080 --> 00:36:10,799 Speaker 1: is sort of similar it. Ultimately, when you get down 578 00:36:10,800 --> 00:36:14,520 Speaker 1: to the very very very tiny amounts could only be 579 00:36:14,640 --> 00:36:20,160 Speaker 1: omitted or absorbed in discrete chunks. It's not continuous, not analog, 580 00:36:21,600 --> 00:36:25,960 Speaker 1: And this was a revolutionary idea. Einstein would end up 581 00:36:26,200 --> 00:36:29,720 Speaker 1: looking at this idea and saying this is pretty cool. Um, 582 00:36:29,800 --> 00:36:32,719 Speaker 1: I'm gonna use this and add on to it, and 583 00:36:32,760 --> 00:36:37,600 Speaker 1: he created his theory about the photo electric effect. Plank, meanwhile, 584 00:36:37,640 --> 00:36:41,560 Speaker 1: would end up being awarded the Nobel Prize in Physics 585 00:36:41,560 --> 00:36:46,560 Speaker 1: in nineteen eighteen for his his working quantum mechanics. Einstein 586 00:36:46,600 --> 00:36:50,680 Speaker 1: would similarly be honored several times. It was Einstein who 587 00:36:50,680 --> 00:36:53,920 Speaker 1: first suggested that Adams might be able to produce photons 588 00:36:53,960 --> 00:36:59,400 Speaker 1: through stimulated emission. So lasers are somewhat built upon the 589 00:36:59,400 --> 00:37:03,080 Speaker 1: theories of Einstein himself. He stated that electrons could be 590 00:37:03,080 --> 00:37:05,759 Speaker 1: stimulated to a mid light of a specific wavelength, which 591 00:37:05,760 --> 00:37:08,960 Speaker 1: of course is the very basis of lasers. And Einstein 592 00:37:09,000 --> 00:37:13,239 Speaker 1: published that theory in nineteen seventeen, so it would be 593 00:37:13,280 --> 00:37:17,080 Speaker 1: nearly forty years before anyone could actually build something to 594 00:37:17,200 --> 00:37:22,640 Speaker 1: test out and see if Einstein's theory was of practical application. Uh, 595 00:37:23,320 --> 00:37:26,040 Speaker 1: but it turns out he was right, which again blows 596 00:37:26,080 --> 00:37:30,120 Speaker 1: my mind. Forty years before anyone could build something, and 597 00:37:30,160 --> 00:37:35,480 Speaker 1: he's saying, hey, you know what probably would work. Ah, 598 00:37:35,840 --> 00:37:38,440 Speaker 1: I'm oversimplifying it and making light of it. But I 599 00:37:38,480 --> 00:37:40,959 Speaker 1: am in awe of people who are able to think 600 00:37:41,040 --> 00:37:45,080 Speaker 1: in these terms, where they're able to work out the 601 00:37:45,120 --> 00:37:48,640 Speaker 1: basic laws of the universe well before we could ever 602 00:37:48,680 --> 00:37:52,719 Speaker 1: make any sort of practical attempt to test those ideas. 603 00:37:52,800 --> 00:37:55,319 Speaker 1: It is phenomenal to me. Now. Granted, I could make 604 00:37:55,440 --> 00:37:58,000 Speaker 1: up laws of the universe, but they would be completely 605 00:37:58,040 --> 00:38:01,080 Speaker 1: unsubstantiated and would face old to hold up to any 606 00:38:01,160 --> 00:38:03,680 Speaker 1: testing in the future. I lack the ability to have 607 00:38:03,800 --> 00:38:06,880 Speaker 1: that level of insight into how our universe works. But 608 00:38:06,960 --> 00:38:11,080 Speaker 1: I do appreciate it in others. So let's flash forward 609 00:38:11,360 --> 00:38:14,680 Speaker 1: the nineteen fifty one. So we go from nineteen seventeen 610 00:38:14,680 --> 00:38:19,080 Speaker 1: to nineteen fifty one. That's when a guy named Charles H. Towns, 611 00:38:19,600 --> 00:38:23,480 Speaker 1: who worked at Columbia University in New York, was sitting 612 00:38:23,480 --> 00:38:26,960 Speaker 1: on a park bench, which in itself is not that remarkable, 613 00:38:27,400 --> 00:38:30,279 Speaker 1: but he came up with an idea of creating a 614 00:38:30,280 --> 00:38:34,760 Speaker 1: device that could produce microwaves through stimulated emission of radiation, 615 00:38:35,360 --> 00:38:39,239 Speaker 1: and this idea became the basis of the Mazer m 616 00:38:39,320 --> 00:38:43,320 Speaker 1: a s E er, which is similar to the laser, 617 00:38:43,360 --> 00:38:47,359 Speaker 1: but obviously amidst microwaves rather than light. Three years later, 618 00:38:47,800 --> 00:38:51,880 Speaker 1: Towns would demonstrate a working maser. So this is nineteen 619 00:38:51,960 --> 00:38:56,279 Speaker 1: fifty four, not a laser, yet still a mazer. So 620 00:38:56,400 --> 00:38:59,239 Speaker 1: microwaves are part of the electromagnetic spectrum, but are not 621 00:38:59,400 --> 00:39:03,080 Speaker 1: considered of light. Right, you've gone beyond infrared at this point. 622 00:39:03,120 --> 00:39:06,560 Speaker 1: The wavelengths of microwaves are much much, much longer than 623 00:39:06,800 --> 00:39:10,520 Speaker 1: the wavelengths of light. Towns had actually partnered with a 624 00:39:10,520 --> 00:39:13,120 Speaker 1: couple of people in order to create this working maser 625 00:39:13,239 --> 00:39:16,480 Speaker 1: that included Herbert J. Zeiger and a graduate student named 626 00:39:16,560 --> 00:39:20,640 Speaker 1: James P. Gordon. They used ammonia as their medium for 627 00:39:20,680 --> 00:39:24,520 Speaker 1: the mazer, and the wavelength of the microwave was one centimeter. 628 00:39:25,239 --> 00:39:30,640 Speaker 1: A centimeter is it's it's almost impossible for me to 629 00:39:30,960 --> 00:39:35,040 Speaker 1: describe how big that is compared to the the waves 630 00:39:35,080 --> 00:39:37,960 Speaker 1: that are in the nanometer range, the hundreds of nanometers, 631 00:39:38,719 --> 00:39:41,840 Speaker 1: but it is while centimeter is small to us, it 632 00:39:41,960 --> 00:39:46,960 Speaker 1: is enormous in the quantum world. So they were able 633 00:39:47,000 --> 00:39:49,400 Speaker 1: to create this. They were able to build a working 634 00:39:49,480 --> 00:39:56,800 Speaker 1: maser using ammonia as their medium. Now in Moscow around 635 00:39:56,800 --> 00:40:00,080 Speaker 1: the same time, there are a couple of engineers, Nikolai G. 636 00:40:00,280 --> 00:40:04,880 Speaker 1: Basov and Alexander M. Prokhorov, who were working on building 637 00:40:04,920 --> 00:40:08,080 Speaker 1: oscillators at the time, and while they were building oscillators, 638 00:40:08,080 --> 00:40:11,319 Speaker 1: they came up with a method that they thought would 639 00:40:11,360 --> 00:40:15,000 Speaker 1: work for negative absorption while building these things, and they 640 00:40:15,040 --> 00:40:18,560 Speaker 1: called it the pumping method, which would become important for 641 00:40:18,840 --> 00:40:24,839 Speaker 1: future mazers and lasers. In nineteen fifty six, Nicholas Blomberg 642 00:40:24,960 --> 00:40:29,279 Speaker 1: in at Harvard develops the first solid state mazer. In 643 00:40:29,320 --> 00:40:33,080 Speaker 1: September nineteen fifty seven, Towns would sketch out an optical 644 00:40:33,400 --> 00:40:37,520 Speaker 1: mazer design in a lab notebook. Also in nineteen fifty seven, 645 00:40:37,520 --> 00:40:40,080 Speaker 1: there was a guy named Gordon Gould who was a 646 00:40:40,120 --> 00:40:42,760 Speaker 1: grad student at Columbia who wrote down his own ideas 647 00:40:42,760 --> 00:40:44,800 Speaker 1: for a device that would be similar to a mazer, 648 00:40:45,160 --> 00:40:48,920 Speaker 1: but he called this one a laser. So this appears 649 00:40:48,960 --> 00:40:51,799 Speaker 1: to be the first use of the word lasers, the 650 00:40:51,840 --> 00:40:56,480 Speaker 1: first recorded instance of laser as a word. And Gould 651 00:40:56,560 --> 00:41:00,480 Speaker 1: thought ahead and even had his notes notarized. So he 652 00:41:00,560 --> 00:41:04,239 Speaker 1: had them notarized by a notary, well as a date 653 00:41:04,280 --> 00:41:06,359 Speaker 1: on it and everything, so that he could prove that 654 00:41:06,400 --> 00:41:09,319 Speaker 1: he had come up with this notion. He tracked down 655 00:41:09,320 --> 00:41:13,480 Speaker 1: a notary at a candy shop and the bronx, which 656 00:41:13,840 --> 00:41:17,319 Speaker 1: is a phenomenal story in my mind. I love the 657 00:41:17,360 --> 00:41:21,000 Speaker 1: idea that this is non joke. This really happened. You 658 00:41:21,080 --> 00:41:23,560 Speaker 1: had a guy come up with what would become a 659 00:41:23,680 --> 00:41:29,280 Speaker 1: transformative technology, a laser, like the idea of creating a 660 00:41:29,400 --> 00:41:33,319 Speaker 1: light version of what had already happened, And so he 661 00:41:33,360 --> 00:41:36,080 Speaker 1: needs it notarized, so he goes to a candy store. 662 00:41:37,400 --> 00:41:40,440 Speaker 1: It's pretty sweet when you think about it. By nineteen 663 00:41:40,520 --> 00:41:43,160 Speaker 1: fifty eight, Towns was working with his brother in law, 664 00:41:43,400 --> 00:41:47,640 Speaker 1: Arthur L. Shallow or Shallow, I guess is the way 665 00:41:47,640 --> 00:41:50,480 Speaker 1: you would pronounce it sc h A W l O 666 00:41:50,760 --> 00:41:54,239 Speaker 1: W Shallow. He was a researcher for Bell Labs, which 667 00:41:54,280 --> 00:41:57,920 Speaker 1: obviously has played an enormously important role in the development 668 00:41:57,920 --> 00:42:02,680 Speaker 1: of electronics in general. Together they proposed developing masers that 669 00:42:02,680 --> 00:42:05,279 Speaker 1: could operate in the infrared and optical parts of the 670 00:42:05,320 --> 00:42:09,960 Speaker 1: electromagnetic spectrum. And meanwhile, over in Russia, Prokhorov and Basov 671 00:42:10,200 --> 00:42:14,440 Speaker 1: were also investigating the possibility of developing optical mazers. So 672 00:42:14,480 --> 00:42:16,680 Speaker 1: the race was on a lot of different people all 673 00:42:16,719 --> 00:42:21,560 Speaker 1: trying to create an optical mazer or laser. In April 674 00:42:21,640 --> 00:42:25,120 Speaker 1: nineteen fifty nine, Gould would apply for patents relating to lasers, 675 00:42:25,400 --> 00:42:30,160 Speaker 1: and in nineteen sixty Townsend Shallow received a patent for 676 00:42:30,239 --> 00:42:33,920 Speaker 1: the optical mazer, which they now were calling a laser, 677 00:42:34,320 --> 00:42:38,680 Speaker 1: and thus the Great Laser Battle began. Only this laser 678 00:42:38,719 --> 00:42:42,400 Speaker 1: battle wasn't fought with lasers. It was fought over the 679 00:42:42,440 --> 00:42:47,000 Speaker 1: intellectual property represented by lasers. And this was a legal 680 00:42:47,040 --> 00:42:50,759 Speaker 1: battle that would stretch for three decades. So an incredible 681 00:42:50,920 --> 00:42:55,480 Speaker 1: laser battle really. But the first working laser was built 682 00:42:55,520 --> 00:43:00,080 Speaker 1: in Malibu, California, in nineteen sixty and almost certain he 683 00:43:00,120 --> 00:43:03,839 Speaker 1: had nothing to do with plastic surgery, unlike everything else. 684 00:43:03,880 --> 00:43:08,359 Speaker 1: In Malibu, California, Theodore H. Maiman, who worked at Hughes 685 00:43:08,440 --> 00:43:11,959 Speaker 1: Research Labs in Malibu, built this first laser. He used 686 00:43:11,960 --> 00:43:15,120 Speaker 1: a synthetic ruby that was two centimeters long and one 687 00:43:15,160 --> 00:43:18,640 Speaker 1: centimeter in diameter, and he coated the ends in silver 688 00:43:18,800 --> 00:43:22,719 Speaker 1: to make them reflective. He used a photographic flash lamp 689 00:43:23,040 --> 00:43:25,920 Speaker 1: to pump the lasing materials, so he used the exact 690 00:43:25,920 --> 00:43:27,640 Speaker 1: same sort of flash bulbs you would find in a 691 00:43:27,680 --> 00:43:30,640 Speaker 1: cameras flash, which is pretty incredible. And a couple of 692 00:43:30,680 --> 00:43:33,680 Speaker 1: months later, Hughes Research would hold a press conference to 693 00:43:33,719 --> 00:43:37,200 Speaker 1: announce that they had developed the first working laser. A 694 00:43:37,200 --> 00:43:41,120 Speaker 1: few months after that, scientists at IBMS Thomas J. Watson 695 00:43:41,200 --> 00:43:46,440 Speaker 1: Research Center demonstrated a working uranium laser, which seems like 696 00:43:46,480 --> 00:43:51,640 Speaker 1: a massive show of escalation in my mind. Now, at 697 00:43:51,640 --> 00:43:54,719 Speaker 1: this point the developments would come really fast and furious, 698 00:43:55,560 --> 00:43:58,239 Speaker 1: not like the film series within Diesel, but I mean 699 00:43:58,280 --> 00:44:03,640 Speaker 1: they were just laser development after laser development, tons of advances. 700 00:44:03,640 --> 00:44:05,239 Speaker 1: I'm not going to cover all of them because they're 701 00:44:05,280 --> 00:44:07,120 Speaker 1: way too many, but I'll cover some of the big ones. 702 00:44:07,600 --> 00:44:10,239 Speaker 1: The first helium neon laser debut at the end of 703 00:44:10,320 --> 00:44:13,279 Speaker 1: nineteen sixty, again at Bell Labs, and it was able 704 00:44:13,280 --> 00:44:16,640 Speaker 1: to create a one point one five micrometer wavelength of 705 00:44:16,680 --> 00:44:20,880 Speaker 1: continuous light, so beyond the range of human vision. It 706 00:44:20,920 --> 00:44:23,960 Speaker 1: wasn't light that was visible, but it was in the 707 00:44:24,000 --> 00:44:28,240 Speaker 1: spectrum of light. And in nineteen sixty one companies began 708 00:44:28,280 --> 00:44:32,000 Speaker 1: to manufacture lasers for the market. This is incredible to me. 709 00:44:32,080 --> 00:44:34,759 Speaker 1: It what had been only a year since someone had 710 00:44:34,760 --> 00:44:38,200 Speaker 1: built a working laser, and by the following year people 711 00:44:38,280 --> 00:44:42,440 Speaker 1: were making them for for sale. Now, granted, they weren't 712 00:44:42,480 --> 00:44:46,600 Speaker 1: selling them to average consumers. It's not like John Smith 713 00:44:46,760 --> 00:44:49,279 Speaker 1: or or or John Q. Public if you prefer it, 714 00:44:49,320 --> 00:44:53,720 Speaker 1: could walk into the closest laser store in order a laser. 715 00:44:54,040 --> 00:44:57,520 Speaker 1: These were meant for research and development purposes and not 716 00:44:57,719 --> 00:45:01,320 Speaker 1: for people who wanted to amuse their cat. It was 717 00:45:01,360 --> 00:45:03,719 Speaker 1: also meant for some early industrial uses and as it 718 00:45:03,760 --> 00:45:07,000 Speaker 1: turns out, some early medical uses. So again I'm gonna 719 00:45:07,040 --> 00:45:10,000 Speaker 1: jump over some of the incremental developments. It wouldn't make 720 00:45:10,040 --> 00:45:11,400 Speaker 1: sense for me to cover all of them, and a 721 00:45:11,400 --> 00:45:12,759 Speaker 1: lot of them I would have to go into even 722 00:45:12,760 --> 00:45:17,320 Speaker 1: more description about very specific types of lasers which only 723 00:45:17,360 --> 00:45:21,680 Speaker 1: apply to particular cases and not to others, and that 724 00:45:21,680 --> 00:45:25,239 Speaker 1: would just make this kind of muddy and and and directionless. 725 00:45:25,440 --> 00:45:27,160 Speaker 1: But I do want to point out a few really 726 00:45:27,160 --> 00:45:30,719 Speaker 1: cool moments in history and explain some related topics to 727 00:45:30,880 --> 00:45:35,400 Speaker 1: lasers as a result, such as what happened in December 728 00:45:35,440 --> 00:45:38,520 Speaker 1: of nineteen sixty one. So keep in mind it only 729 00:45:38,560 --> 00:45:40,960 Speaker 1: been a bit longer than a year since someone had 730 00:45:40,960 --> 00:45:45,040 Speaker 1: demonstrated a working laser at all. But in December nineteen 731 00:45:45,080 --> 00:45:49,640 Speaker 1: sixty one, Dr Charles J. Campbell and Charles J. Custer, 732 00:45:50,840 --> 00:45:54,080 Speaker 1: I'll have Charles Jay's decided that they were going to 733 00:45:54,160 --> 00:45:58,240 Speaker 1: treat a patient, a medical patient, a human medical patient, 734 00:45:58,680 --> 00:46:02,800 Speaker 1: using an optical be laser to destroy a retinal tumor. 735 00:46:03,800 --> 00:46:07,080 Speaker 1: Now that's incredible. It had been only eighteen months since 736 00:46:07,120 --> 00:46:10,160 Speaker 1: someone had built the first working laser, and you already 737 00:46:10,160 --> 00:46:13,600 Speaker 1: had people using it in a medical procedure on a 738 00:46:13,719 --> 00:46:18,239 Speaker 1: human patient. I suspect that today it would take a 739 00:46:18,280 --> 00:46:22,200 Speaker 1: bit longer to prove that the methodology being used was 740 00:46:22,560 --> 00:46:26,600 Speaker 1: safe and efficacious before using it on a human, but 741 00:46:26,840 --> 00:46:29,239 Speaker 1: it shows how quickly things were moving back then. I 742 00:46:29,239 --> 00:46:32,040 Speaker 1: think it's pretty incredible that it took less than two 743 00:46:32,160 --> 00:46:35,359 Speaker 1: years to actually use lasers in a medical and an 744 00:46:35,360 --> 00:46:39,520 Speaker 1: actual medical procedure. Now, the mid nineteen sixties would see 745 00:46:39,520 --> 00:46:42,560 Speaker 1: advances in the field of fiber optics, which, when paired 746 00:46:42,600 --> 00:46:46,000 Speaker 1: with lasers, allow for long distance communication using light through 747 00:46:46,040 --> 00:46:49,240 Speaker 1: glass filaments. Now, I've done episodes about fiber optics before, 748 00:46:49,280 --> 00:46:50,759 Speaker 1: so you can go and look at the Tech Stuff 749 00:46:50,840 --> 00:46:53,520 Speaker 1: archives and learn more about that. But this still blows 750 00:46:53,560 --> 00:46:56,040 Speaker 1: my mind too. Just the fact that fiber optics are 751 00:46:56,120 --> 00:47:00,680 Speaker 1: a thing that work, it is incredible to me. Meanwhile, 752 00:47:00,800 --> 00:47:03,520 Speaker 1: Bell Labs would strike again in nineteen seventy two with 753 00:47:03,560 --> 00:47:06,560 Speaker 1: a laser beam cutter they used to form electronic circuit 754 00:47:06,600 --> 00:47:12,600 Speaker 1: patterns on ceramic and on June nineteen seventy four, which 755 00:47:13,280 --> 00:47:15,800 Speaker 1: just for Trivia's sake, is exactly one year to the 756 00:47:15,920 --> 00:47:21,080 Speaker 1: day before I was born. A barcode scanner, which typically 757 00:47:21,160 --> 00:47:25,480 Speaker 1: uses lasers. Read the very first product ever registered for 758 00:47:25,680 --> 00:47:29,640 Speaker 1: real z s using a UPC code and a barcode scanner. 759 00:47:30,040 --> 00:47:31,839 Speaker 1: The product, by the way, it was a pack of 760 00:47:31,920 --> 00:47:35,920 Speaker 1: Wriggley's chewing gum. So how the heck did those barcode 761 00:47:35,920 --> 00:47:38,640 Speaker 1: scanners work? Because you see him on everything these days 762 00:47:38,840 --> 00:47:40,200 Speaker 1: and here's where I'm gonna go on a bit of 763 00:47:40,239 --> 00:47:43,640 Speaker 1: a tangent to talk about bar codes in just a second. 764 00:47:44,120 --> 00:47:46,920 Speaker 1: And I also just want to mention that, uh, I 765 00:47:46,920 --> 00:47:49,080 Speaker 1: think it's really cool that, now you know a trivia 766 00:47:49,200 --> 00:47:52,439 Speaker 1: question that the first product to ever be scanned using 767 00:47:52,440 --> 00:47:56,280 Speaker 1: a barcode scanner was Wriggley's chewing gum. Important to remember 768 00:47:56,320 --> 00:47:58,839 Speaker 1: in case you ever played bar trivia. Now, next, I'm 769 00:47:58,880 --> 00:48:01,560 Speaker 1: gonna talk all about you PC codes and how they work. 770 00:48:02,080 --> 00:48:05,000 Speaker 1: But before I jump into that and go way off 771 00:48:05,040 --> 00:48:08,560 Speaker 1: the rails, let's take another quick break to fake our sponsor. 772 00:48:15,480 --> 00:48:18,120 Speaker 1: All right, So let's talk about bar codes, which are 773 00:48:18,400 --> 00:48:22,160 Speaker 1: I agree, tangentially related to lasers. But I've already talked 774 00:48:22,160 --> 00:48:25,399 Speaker 1: about how lasers work, and I really love how bar 775 00:48:25,480 --> 00:48:28,560 Speaker 1: codes work because I just think they're kind of cool. 776 00:48:29,040 --> 00:48:31,880 Speaker 1: So these are the good old universal product code or 777 00:48:32,080 --> 00:48:36,120 Speaker 1: UPC code things that you would see on products today 778 00:48:36,520 --> 00:48:40,000 Speaker 1: at your average store. Uh. They were designed in order 779 00:48:40,000 --> 00:48:42,319 Speaker 1: to help speed up check out and also make it 780 00:48:42,360 --> 00:48:46,680 Speaker 1: easier to keep a working inventory of a store. And 781 00:48:46,719 --> 00:48:49,399 Speaker 1: you can just scan each item and then you use 782 00:48:49,440 --> 00:48:53,680 Speaker 1: a computer database to match the scan with other information 783 00:48:53,880 --> 00:48:57,600 Speaker 1: like what that product is, how much it costs. So 784 00:48:57,840 --> 00:49:00,080 Speaker 1: the scanner all it needs to do is ident a 785 00:49:00,200 --> 00:49:04,120 Speaker 1: fi which product you are actually scanning at any given time. 786 00:49:04,320 --> 00:49:07,440 Speaker 1: That's its only job. It doesn't really have anything to 787 00:49:07,480 --> 00:49:10,879 Speaker 1: do with how much something costs. That is not necessarily 788 00:49:10,920 --> 00:49:13,880 Speaker 1: represented in the code itself. There are codes that do 789 00:49:13,960 --> 00:49:17,280 Speaker 1: have the information in them, but the basic UPC code 790 00:49:17,600 --> 00:49:20,920 Speaker 1: is really just to tell a system what the product is, 791 00:49:21,440 --> 00:49:24,880 Speaker 1: and then you have a separate database that links products 792 00:49:24,960 --> 00:49:29,520 Speaker 1: to prices. So what would you do if you were 793 00:49:29,560 --> 00:49:33,800 Speaker 1: a manufacturer and you wanted to put a UPC code 794 00:49:34,400 --> 00:49:38,200 Speaker 1: on something that you yourself were making, your company was making. 795 00:49:39,000 --> 00:49:41,760 Speaker 1: Here's the process. You have a company called the Uniform 796 00:49:42,080 --> 00:49:45,680 Speaker 1: Code Council or you see C, and they are in 797 00:49:45,840 --> 00:49:50,200 Speaker 1: charge of UPC codes. And to me, the u c 798 00:49:50,360 --> 00:49:52,880 Speaker 1: C sounds like it should be staffed by shadowy figures 799 00:49:52,880 --> 00:49:55,279 Speaker 1: in robes. But to be fair, I did watch Hot 800 00:49:55,320 --> 00:49:57,839 Speaker 1: Fuzz again not too long ago, and that's probably why 801 00:49:57,880 --> 00:50:01,520 Speaker 1: I'm thinking that. So let's say you're a manufacturing company 802 00:50:01,600 --> 00:50:04,200 Speaker 1: and you make a very specific product and you want 803 00:50:04,280 --> 00:50:09,120 Speaker 1: to get it into stores around the world. And since 804 00:50:09,160 --> 00:50:13,000 Speaker 1: the earliest implementations of the UPC codes were for grocery stores, 805 00:50:13,680 --> 00:50:16,839 Speaker 1: Let's say that it's a grocery store products. So let's 806 00:50:16,840 --> 00:50:20,560 Speaker 1: say you're making a really awesome, tasty, sugary breakfast cereal 807 00:50:20,600 --> 00:50:25,640 Speaker 1: for kids, and you're calling them Crispy Doos. So you 808 00:50:25,680 --> 00:50:28,960 Speaker 1: make delicious Crispy doos that are a nutritional part of 809 00:50:28,960 --> 00:50:32,320 Speaker 1: a balanced breakfast. You want to sell Crispy doos and 810 00:50:32,400 --> 00:50:36,200 Speaker 1: grocery stores, so you want to end up selling to 811 00:50:36,320 --> 00:50:39,040 Speaker 1: grocery stores. Grocery stores will sell the Crispy dues too 812 00:50:39,640 --> 00:50:46,200 Speaker 1: to their their customers and everyone benefits, presumably assuming that 813 00:50:46,239 --> 00:50:48,880 Speaker 1: there's enough nutritional value in the Crispy dues to not, 814 00:50:49,400 --> 00:50:54,920 Speaker 1: you know, turn your customers into goo. So grocery stores 815 00:50:55,000 --> 00:50:58,239 Speaker 1: love the idea of UPC codes because again, it makes 816 00:50:58,239 --> 00:51:01,520 Speaker 1: it much easier to ring up products and it makes 817 00:51:01,520 --> 00:51:04,279 Speaker 1: it very easy to keep track of the stock that 818 00:51:04,400 --> 00:51:06,800 Speaker 1: the grocery store has. If they notice that they're selling, 819 00:51:07,640 --> 00:51:10,319 Speaker 1: you know, eight palettes of Crispy Doos a week, then 820 00:51:10,360 --> 00:51:13,160 Speaker 1: they might up their order and that's good for you. 821 00:51:13,320 --> 00:51:16,440 Speaker 1: So it benefits you to get a UBC code on 822 00:51:16,560 --> 00:51:19,840 Speaker 1: your product. To do that, you would first have to 823 00:51:19,880 --> 00:51:24,640 Speaker 1: apply for a manufacturer identification number from the u c C. 824 00:51:25,080 --> 00:51:27,120 Speaker 1: This is almost like a subscription service. You'd have to 825 00:51:27,120 --> 00:51:32,160 Speaker 1: pay the u c C to get this manufacturer identification number. Uh, 826 00:51:32,320 --> 00:51:35,520 Speaker 1: the u c C would then issue you this number. 827 00:51:35,560 --> 00:51:38,080 Speaker 1: It's a six digit number. And if you look at 828 00:51:38,080 --> 00:51:41,040 Speaker 1: a UPC code, you'll see that there are twelve digits 829 00:51:41,040 --> 00:51:45,160 Speaker 1: on the UPC code. So those are the human readable digits, right, 830 00:51:45,200 --> 00:51:46,640 Speaker 1: that's the thing that you have to type in, and 831 00:51:46,719 --> 00:51:49,239 Speaker 1: for some reason the scanner is not scanning anything you 832 00:51:49,320 --> 00:51:52,600 Speaker 1: might type in the code. Well, those first six digits 833 00:51:52,840 --> 00:51:58,160 Speaker 1: refer to the manufacturer identification number, So all the products 834 00:51:58,600 --> 00:52:02,360 Speaker 1: from that specific manufact acturer should have those first six 835 00:52:02,560 --> 00:52:06,640 Speaker 1: numbers the same on all of them because it's it's 836 00:52:06,840 --> 00:52:10,320 Speaker 1: unique to the company itself. It doesn't matter what the 837 00:52:10,360 --> 00:52:16,040 Speaker 1: product is. The next five digits on that UPC code 838 00:52:16,440 --> 00:52:21,120 Speaker 1: represent the item number, so it's unique to the product. 839 00:52:21,640 --> 00:52:25,120 Speaker 1: So if you make fourteen different products, each product is 840 00:52:25,160 --> 00:52:28,320 Speaker 1: going to have its same or its own five digit 841 00:52:28,920 --> 00:52:31,239 Speaker 1: item code, and it will be different from the other 842 00:52:31,320 --> 00:52:36,280 Speaker 1: thirteen item codes. So if your company also produced, say 843 00:52:36,280 --> 00:52:40,120 Speaker 1: Flea colors for kitty cats, the five digits for the 844 00:52:40,120 --> 00:52:42,080 Speaker 1: fleet colors are going to be different than the five 845 00:52:42,120 --> 00:52:44,400 Speaker 1: digits for the Crispy Dues. Which is good because you 846 00:52:44,440 --> 00:52:46,560 Speaker 1: don't want to mix up your Flea colors with your 847 00:52:46,600 --> 00:52:50,440 Speaker 1: Crispy Dues. That would be a pr nightmare, and this 848 00:52:50,480 --> 00:52:52,759 Speaker 1: episode really isn't meant to go into that sort of thing. 849 00:52:53,680 --> 00:52:57,640 Speaker 1: So that leaves one digit left over. Right, You've got 850 00:52:57,680 --> 00:53:00,560 Speaker 1: the first six that's the manufacturer I D number, the 851 00:53:00,600 --> 00:53:05,040 Speaker 1: next five which is the item number. But you have 852 00:53:05,080 --> 00:53:08,560 Speaker 1: a single digit leftover of those twelve, so is that 853 00:53:08,640 --> 00:53:12,520 Speaker 1: for That is called the check digit, and the check 854 00:53:12,560 --> 00:53:16,920 Speaker 1: digit is meant to give the scanner the opportunity to 855 00:53:17,360 --> 00:53:22,840 Speaker 1: verify that it has scanned the product properly. And the 856 00:53:22,880 --> 00:53:26,200 Speaker 1: way you do this is through some pretty ridiculous math. 857 00:53:26,400 --> 00:53:32,160 Speaker 1: It's not difficult, it's just tedious. So it's again a 858 00:53:32,280 --> 00:53:36,800 Speaker 1: verification right to say that, yes, the scan went through properly, 859 00:53:36,880 --> 00:53:40,279 Speaker 1: because if the math checks out, if you get the 860 00:53:40,320 --> 00:53:44,160 Speaker 1: answer you're supposed to get, you know that you scanned 861 00:53:44,160 --> 00:53:47,080 Speaker 1: it properly. And by you, I mean the scanner system 862 00:53:47,160 --> 00:53:50,760 Speaker 1: is able to verify that a scan went through correctly. 863 00:53:51,640 --> 00:53:54,160 Speaker 1: So let's take a second to talk about how you 864 00:53:54,320 --> 00:53:57,319 Speaker 1: arrive at the check digit so you can understand what 865 00:53:57,360 --> 00:53:59,920 Speaker 1: I mean when you do some ridiculous arithmetic it's not 866 00:54:00,160 --> 00:54:05,040 Speaker 1: difficult again, it's just ridiculous. So you've got eleven other 867 00:54:05,120 --> 00:54:08,160 Speaker 1: digits in the UPC code, and those are what you 868 00:54:08,280 --> 00:54:12,719 Speaker 1: use to do the arithmetic. First, you take all the numbers, 869 00:54:12,760 --> 00:54:15,640 Speaker 1: all the digits and the UPC codes that are at 870 00:54:15,640 --> 00:54:19,279 Speaker 1: odd positions, so not the odd numbers, just in the 871 00:54:19,320 --> 00:54:22,120 Speaker 1: odd positions. So that would be the position number one, 872 00:54:22,239 --> 00:54:26,320 Speaker 1: position number three, five, et cetera, up to eleven. Because 873 00:54:26,320 --> 00:54:30,400 Speaker 1: you have eleven other numbers, you take all of those 874 00:54:30,719 --> 00:54:32,879 Speaker 1: and you add them together and you get a sum. 875 00:54:33,640 --> 00:54:36,560 Speaker 1: So you've got that sum by adding all the odd 876 00:54:36,560 --> 00:54:40,399 Speaker 1: position numbers together, and you then multiply that by three. 877 00:54:41,560 --> 00:54:43,799 Speaker 1: Now you look at all the digits that are in 878 00:54:44,040 --> 00:54:48,520 Speaker 1: even positions, so two, four, six, eight, and ten, you 879 00:54:48,640 --> 00:54:52,720 Speaker 1: add all of those together. You then take the number 880 00:54:52,760 --> 00:54:55,479 Speaker 1: you got from all the odd positions multiplied by three, 881 00:54:55,880 --> 00:54:59,040 Speaker 1: and all the even positions added together, and you add 882 00:54:59,080 --> 00:55:02,160 Speaker 1: those two numbers to other, and then you take a 883 00:55:02,160 --> 00:55:06,439 Speaker 1: look at this new number, this monstrosity of a thing. 884 00:55:07,120 --> 00:55:09,719 Speaker 1: It's not a huge number, it's just weird that you've 885 00:55:09,719 --> 00:55:12,560 Speaker 1: got it. And you say, all right, how many more 886 00:55:13,040 --> 00:55:15,800 Speaker 1: numbers would I have to add to this in order 887 00:55:15,840 --> 00:55:22,160 Speaker 1: to get a multiple of ten, and as long as 888 00:55:22,719 --> 00:55:27,000 Speaker 1: the last digit is the same as the number you 889 00:55:27,080 --> 00:55:30,800 Speaker 1: need to add to your your monstrosity to get a 890 00:55:30,880 --> 00:55:33,719 Speaker 1: multiple of ten, you're good to go. So this is 891 00:55:33,760 --> 00:55:37,800 Speaker 1: easier to understand with an example. So here's our UPC code. 892 00:55:38,120 --> 00:55:41,360 Speaker 1: We've got our crispy doos, and our UPC code happens 893 00:55:41,400 --> 00:55:46,920 Speaker 1: to be six three nine three eight two zero zero 894 00:55:47,000 --> 00:55:52,040 Speaker 1: zero three nine three. Well, that last three is the 895 00:55:52,120 --> 00:55:54,799 Speaker 1: check digit. That's the number we're supposed to get at 896 00:55:54,800 --> 00:55:56,719 Speaker 1: the end of all this other nonsense. So we put 897 00:55:56,719 --> 00:55:59,799 Speaker 1: that aside. We say three is what we're hoping is 898 00:55:59,840 --> 00:56:02,879 Speaker 1: the outcome. How do we get to that. We take 899 00:56:02,920 --> 00:56:07,880 Speaker 1: all those odd positioned digits, which would be six and 900 00:56:08,120 --> 00:56:11,759 Speaker 1: nine and eight, etcetera, etcetera. We add them all up. 901 00:56:12,200 --> 00:56:16,360 Speaker 1: Technically it's six to zeros and nine. That gets you 902 00:56:16,400 --> 00:56:19,719 Speaker 1: thirty two. You multiply that number by three, you get 903 00:56:19,840 --> 00:56:22,319 Speaker 1: ninety six. So that's your that's your first number. You 904 00:56:22,320 --> 00:56:24,239 Speaker 1: set that aside. Your ninety six is good to go. 905 00:56:24,880 --> 00:56:27,520 Speaker 1: Then you take a look at all the even positioned 906 00:56:27,680 --> 00:56:30,480 Speaker 1: numbers and you add those up. The even position numbers 907 00:56:30,480 --> 00:56:33,719 Speaker 1: would be a three, A three, two, zero, and another three. 908 00:56:33,800 --> 00:56:37,040 Speaker 1: That gives you eleven. So now you add the eleven 909 00:56:37,160 --> 00:56:39,719 Speaker 1: to the ninety six that you arrived at earlier. That 910 00:56:39,760 --> 00:56:41,840 Speaker 1: gives you a hundred and seven. You look at a 911 00:56:41,920 --> 00:56:44,040 Speaker 1: hundred and seven and say, how many digits or how 912 00:56:44,120 --> 00:56:45,480 Speaker 1: much when I need to add to this to make 913 00:56:45,520 --> 00:56:49,279 Speaker 1: a multiple of ten? Answers three, because if you had 914 00:56:49,280 --> 00:56:52,759 Speaker 1: three seven you get a hundred and ten hundred ts 915 00:56:52,880 --> 00:56:58,040 Speaker 1: multiple of ten. There you go. Three is the number 916 00:56:58,080 --> 00:57:00,760 Speaker 1: you wanted. Three is the number that's the check digit. 917 00:57:00,920 --> 00:57:03,160 Speaker 1: You know that you've got the right answer. Now. The 918 00:57:03,160 --> 00:57:05,839 Speaker 1: way the scanner does this is not by looking at 919 00:57:05,840 --> 00:57:10,080 Speaker 1: the digits. It's looking at the relationship between the thin 920 00:57:11,360 --> 00:57:15,839 Speaker 1: uh bars, the gaps between the bars, and how thick 921 00:57:15,960 --> 00:57:18,600 Speaker 1: or thin each of those are. Right. So, if you 922 00:57:18,640 --> 00:57:21,600 Speaker 1: look at a UPC bar code, you're looking at just 923 00:57:21,760 --> 00:57:23,680 Speaker 1: the bars. You'll see some of the bars are thin, 924 00:57:23,960 --> 00:57:26,200 Speaker 1: some of the bars are a little thicker, some of 925 00:57:26,240 --> 00:57:28,600 Speaker 1: the gaps between the bars are thinner or thicker than 926 00:57:28,640 --> 00:57:33,200 Speaker 1: the others. That relationship of bars to gaps and the 927 00:57:33,240 --> 00:57:36,600 Speaker 1: thickness of them tells you what the value is of 928 00:57:36,640 --> 00:57:39,160 Speaker 1: each of those. And if you're really really wanted to, 929 00:57:39,720 --> 00:57:43,280 Speaker 1: you could decode to bar code just by sight once 930 00:57:43,320 --> 00:57:47,120 Speaker 1: you know the basic system of coding, and if you're 931 00:57:47,160 --> 00:57:51,280 Speaker 1: able to determine what is a narrow versus a wide 932 00:57:51,680 --> 00:57:55,800 Speaker 1: bar or gap, because that's very important. So the scanner 933 00:57:55,880 --> 00:57:58,080 Speaker 1: is looking at the series of bars and gaps and 934 00:57:58,160 --> 00:58:02,520 Speaker 1: measuring those those widths, and by measuring it, it then 935 00:58:02,720 --> 00:58:06,280 Speaker 1: is able to match that to a numeric code and 936 00:58:06,440 --> 00:58:09,960 Speaker 1: verify whether or not it matches that check digit at 937 00:58:10,000 --> 00:58:12,000 Speaker 1: the end, and if it does, the scan goes through, 938 00:58:12,440 --> 00:58:15,600 Speaker 1: it gets matched to a product and you're charged however 939 00:58:15,680 --> 00:58:19,400 Speaker 1: much or your crispy dewes. I'm gonna say it's five 940 00:58:20,000 --> 00:58:24,160 Speaker 1: for a BUX, so that's what would pop up. There 941 00:58:24,200 --> 00:58:28,080 Speaker 1: are variations on these UPC codes like zero suppressed number 942 00:58:28,240 --> 00:58:31,120 Speaker 1: UPC codes, which is exactly what sounds like. Any number 943 00:58:31,120 --> 00:58:33,760 Speaker 1: that is a zero that would otherwise appear in the 944 00:58:33,840 --> 00:58:38,640 Speaker 1: code gets emitted omitted rather not emitted, it's omitted from 945 00:58:38,640 --> 00:58:42,200 Speaker 1: the code, so it's shorter, makes a shorter barcode. Uh, 946 00:58:42,400 --> 00:58:46,080 Speaker 1: But not everyone does this. Only some products have this 947 00:58:46,880 --> 00:58:50,280 Speaker 1: AH and the manufacturing I D numbers can have a 948 00:58:50,320 --> 00:58:53,080 Speaker 1: specific meaning as well, depending on what number they start with. 949 00:58:53,200 --> 00:58:56,880 Speaker 1: So if you're manufacturing I D number starts with a two, 950 00:58:57,200 --> 00:59:00,280 Speaker 1: it means that it is a random weight prod ducked. 951 00:59:00,720 --> 00:59:03,320 Speaker 1: And by random weight we mean it's something that doesn't 952 00:59:03,360 --> 00:59:08,200 Speaker 1: come in a specific uniform size and weight over and 953 00:59:08,280 --> 00:59:12,840 Speaker 1: over again. So produce. For example, an apple is gonna 954 00:59:12,880 --> 00:59:14,960 Speaker 1: be its own weight, right, You're not going to get 955 00:59:15,200 --> 00:59:18,560 Speaker 1: two apples of the exact same weight. They're not all uniform. 956 00:59:18,800 --> 00:59:20,480 Speaker 1: Whereas if I go out and buy a box of 957 00:59:20,520 --> 00:59:23,520 Speaker 1: Crispy DU's, it should be more or less the same 958 00:59:23,560 --> 00:59:27,440 Speaker 1: as a comparable Crispy Due box. Now if you have 959 00:59:27,480 --> 00:59:30,320 Speaker 1: if you have different sizes of boxes, then you have 960 00:59:30,440 --> 00:59:33,080 Speaker 1: different item numbers for each of those different sizes. The 961 00:59:33,120 --> 00:59:39,440 Speaker 1: item numbers are specific to a very particular instance of 962 00:59:39,520 --> 00:59:42,640 Speaker 1: an item. So if I've got a large box of 963 00:59:42,680 --> 00:59:45,480 Speaker 1: Crispy Us and a small box of Crispy Dues, each 964 00:59:45,520 --> 00:59:48,240 Speaker 1: of those will have its own five digit item number, 965 00:59:48,440 --> 00:59:52,040 Speaker 1: and thus the bars that correspond with it will be 966 00:59:52,160 --> 00:59:55,800 Speaker 1: slightly different as well. Um, by the way, if you 967 00:59:55,840 --> 00:59:59,320 Speaker 1: wanted to know, like, just as an example, what these 968 00:59:59,360 --> 01:00:04,200 Speaker 1: bars mean, I'm not gonna go through the encoding of 969 01:00:04,280 --> 01:00:07,360 Speaker 1: every single number because it would be kind of silly. 970 01:00:07,400 --> 01:00:09,520 Speaker 1: But let me give you an example. If you want 971 01:00:09,600 --> 01:00:13,480 Speaker 1: to represent the number one in a UPC code. The 972 01:00:13,520 --> 01:00:17,520 Speaker 1: way it would work is that you would use uh first, 973 01:00:17,600 --> 01:00:20,480 Speaker 1: a black bar that is two units wide, so in 974 01:00:20,480 --> 01:00:22,360 Speaker 1: other words, you have to look at the most narrow 975 01:00:22,400 --> 01:00:28,000 Speaker 1: bar on the UPC code that's probably one unit right. 976 01:00:29,320 --> 01:00:32,440 Speaker 1: You would want a bar that's twice that. With the 977 01:00:32,480 --> 01:00:37,200 Speaker 1: bar units go up from one to four, so the 978 01:00:37,240 --> 01:00:40,880 Speaker 1: widest bar will probably be four units wide, the thinness 979 01:00:40,920 --> 01:00:43,000 Speaker 1: will probably one unit wide. You need one that's two 980 01:00:43,080 --> 01:00:46,840 Speaker 1: units wide, followed by a space that is two units wide, 981 01:00:47,160 --> 01:00:50,560 Speaker 1: followed by another black bar that's two units wide, followed 982 01:00:50,560 --> 01:00:54,960 Speaker 1: by a space that is one unit wide. So that 983 01:00:55,160 --> 01:00:59,479 Speaker 1: is the number one in bar code speak, and each 984 01:00:59,520 --> 01:01:02,320 Speaker 1: of the new roles is encoded in a similar way. 985 01:01:02,680 --> 01:01:07,960 Speaker 1: Using these bars and gaps of varying widths and reading 986 01:01:08,000 --> 01:01:12,680 Speaker 1: them by sight is possible but is not practical. But 987 01:01:12,800 --> 01:01:15,120 Speaker 1: when you move one of those bars across the scanner, 988 01:01:16,320 --> 01:01:21,640 Speaker 1: the scanner shoots light, typically red laser light, at the 989 01:01:21,680 --> 01:01:24,640 Speaker 1: bar code, and then a sensor on the scanner is 990 01:01:24,680 --> 01:01:29,080 Speaker 1: looking for reflected light and it can detect those bars 991 01:01:29,120 --> 01:01:32,000 Speaker 1: and gaps based upon the light that gets reflected back 992 01:01:32,080 --> 01:01:36,200 Speaker 1: at the sensor and as long again as that last 993 01:01:36,720 --> 01:01:40,480 Speaker 1: bar or that last digit matches up with the math 994 01:01:40,600 --> 01:01:44,919 Speaker 1: I talked about earlier. It can then ring up the 995 01:01:44,960 --> 01:01:49,160 Speaker 1: product and give you the appropriate price for it. Uh So, really, 996 01:01:49,200 --> 01:01:51,840 Speaker 1: the the interesting thing here is that the laser just 997 01:01:51,920 --> 01:01:55,960 Speaker 1: makes this incredibly efficient. I mean, light travels faster than 998 01:01:56,000 --> 01:01:58,520 Speaker 1: anything else in the world, so it's no surprise that 999 01:01:58,560 --> 01:02:01,240 Speaker 1: you can just swing one of these barcodes by it 1000 01:02:01,320 --> 01:02:04,920 Speaker 1: a really good clip and still get a really solid 1001 01:02:05,240 --> 01:02:08,840 Speaker 1: scan off of it, because that information is going to 1002 01:02:09,520 --> 01:02:12,320 Speaker 1: the code and back to the scanner at the speed 1003 01:02:12,360 --> 01:02:15,000 Speaker 1: of light, so it's not like you're gonna be moving 1004 01:02:15,560 --> 01:02:19,160 Speaker 1: that fast compared to the scanner um and as long 1005 01:02:19,200 --> 01:02:21,800 Speaker 1: as it's got that good fidelity there, then you're gonna 1006 01:02:21,880 --> 01:02:25,240 Speaker 1: get a pretty successful scan. That's why you can zoom 1007 01:02:25,320 --> 01:02:30,600 Speaker 1: stuff past that scanner pretty quickly. Now, let's go back 1008 01:02:30,640 --> 01:02:34,280 Speaker 1: to that timeline that we were talking about earlier. By 1009 01:02:34,400 --> 01:02:38,800 Speaker 1: Laser Diode Labs Incorporated had developed a continuous wave semiconductor 1010 01:02:38,880 --> 01:02:41,880 Speaker 1: laser which would make it possible to transmit telephone conversations 1011 01:02:41,960 --> 01:02:45,160 Speaker 1: via optic fiber, which again blows my mind that you 1012 01:02:45,200 --> 01:02:49,600 Speaker 1: could turn something that's acoustic not just into electricity, which 1013 01:02:49,600 --> 01:02:54,320 Speaker 1: is already magic in my mind, but into light signals. 1014 01:02:55,040 --> 01:02:58,760 Speaker 1: In we got the laser disc, which was the first 1015 01:02:58,800 --> 01:03:03,080 Speaker 1: commercial use of an optical medium, that being something that 1016 01:03:03,480 --> 01:03:06,280 Speaker 1: could be stored on a device that would be read 1017 01:03:06,360 --> 01:03:09,760 Speaker 1: just by laser light alone. Laser discs were a predecessor 1018 01:03:09,800 --> 01:03:12,880 Speaker 1: to other optical based media like compact discs, a K 1019 01:03:13,160 --> 01:03:16,520 Speaker 1: C d s and DVDs and blu rays. The earliest 1020 01:03:16,560 --> 01:03:19,800 Speaker 1: players actually used helium neon laser tubes in order to 1021 01:03:19,840 --> 01:03:22,760 Speaker 1: read the information stored on the discs, but later ones 1022 01:03:22,800 --> 01:03:27,880 Speaker 1: would switch to more affordable infrared laser diodes, so semiconductor 1023 01:03:27,960 --> 01:03:32,240 Speaker 1: based lasers. And as I said earlier, the semiconductor approach 1024 01:03:32,840 --> 01:03:37,040 Speaker 1: was less powerful and less expensive than other methods of 1025 01:03:37,040 --> 01:03:39,880 Speaker 1: generating lasers, so that helped bring the laser disc price 1026 01:03:39,960 --> 01:03:43,120 Speaker 1: down a little bit, but they were pretty expensive and 1027 01:03:43,200 --> 01:03:45,560 Speaker 1: never really took off. I mean, there were people who 1028 01:03:45,640 --> 01:03:50,520 Speaker 1: loved laser discs, but um they never became as popular 1029 01:03:50,720 --> 01:03:56,360 Speaker 1: as vhs or later on DVD players. Now later in night, 1030 01:03:56,400 --> 01:03:59,520 Speaker 1: Philips would announce it was working on the compact disc project, 1031 01:03:59,600 --> 01:04:01,280 Speaker 1: which is kind of funny because I always think of 1032 01:04:01,320 --> 01:04:04,480 Speaker 1: CDs as being either a late eighties or early nineties phenomenon, 1033 01:04:04,560 --> 01:04:08,200 Speaker 1: But it's origins date back to the late seventies, and 1034 01:04:08,440 --> 01:04:12,280 Speaker 1: the first actual CD produced would come out in nineteen two. 1035 01:04:12,280 --> 01:04:14,680 Speaker 1: And here's some more trivia for you if you're ever 1036 01:04:14,760 --> 01:04:17,040 Speaker 1: doing that pub trivia. You remember the first thing with 1037 01:04:17,080 --> 01:04:20,480 Speaker 1: the barcode was Wrigley's Chewing Gum. The first CD to 1038 01:04:20,560 --> 01:04:25,800 Speaker 1: ever be produced was the album fifty Second Street by 1039 01:04:25,840 --> 01:04:29,600 Speaker 1: Billy Joel. That album actually had some pretty good songs 1040 01:04:29,640 --> 01:04:33,320 Speaker 1: on it, uh, including my Life, which would later serve 1041 01:04:33,360 --> 01:04:35,800 Speaker 1: as the original theme song for the Tom Hanks sitcom 1042 01:04:35,880 --> 01:04:39,080 Speaker 1: Bosom Buddies. I guess you could probably tell that I'm 1043 01:04:39,160 --> 01:04:41,800 Speaker 1: I'm patting this episode out a little bit. But this 1044 01:04:41,880 --> 01:04:45,320 Speaker 1: is again useful information if you're ever playing pub trivia. 1045 01:04:45,640 --> 01:04:47,320 Speaker 1: So if you ever hear what was the first album 1046 01:04:47,360 --> 01:04:49,960 Speaker 1: produced on CD, you now know it's fifty second Street 1047 01:04:50,080 --> 01:04:54,560 Speaker 1: by Billy Joel. In nineteen seventy nine, Gould would finally 1048 01:04:54,720 --> 01:04:57,760 Speaker 1: receive a patent that covered a pretty wide range of 1049 01:04:57,840 --> 01:05:00,520 Speaker 1: laser applications, so that meant that he finally won the 1050 01:05:00,600 --> 01:05:04,240 Speaker 1: laser battle. You'll remember that in the previous section I 1051 01:05:04,280 --> 01:05:07,160 Speaker 1: talked about how he had applied for a patent but 1052 01:05:07,520 --> 01:05:11,400 Speaker 1: was essentially denied that patent because of a previous application 1053 01:05:11,840 --> 01:05:16,400 Speaker 1: that had taken the intellectual property Gould had created and notarized. 1054 01:05:16,960 --> 01:05:19,640 Speaker 1: So this was the end of a very long battle 1055 01:05:20,160 --> 01:05:24,120 Speaker 1: uh here well, at least as far as who has 1056 01:05:24,160 --> 01:05:28,120 Speaker 1: the legal right to claim the intellectual property of lasers. 1057 01:05:28,720 --> 01:05:31,280 Speaker 1: But it would be Shallow, who was one of the 1058 01:05:31,280 --> 01:05:35,480 Speaker 1: parties who had filed the other patent back in a 1059 01:05:35,520 --> 01:05:39,040 Speaker 1: couple of decades earlier, three decades earlier, and Blombergen, who 1060 01:05:39,040 --> 01:05:41,800 Speaker 1: had actually received the Nobel Prize in Physics in one 1061 01:05:41,880 --> 01:05:46,920 Speaker 1: for their work in laser spectroscopy. So people were doing 1062 01:05:46,960 --> 01:05:49,920 Speaker 1: well all around in the laser world. In the mid 1063 01:05:50,040 --> 01:05:53,200 Speaker 1: nineteen eighties, research laboratories began to use lasers to manipulate 1064 01:05:53,360 --> 01:05:57,520 Speaker 1: individual atoms, which is really cool. It opened up a 1065 01:05:57,520 --> 01:06:01,080 Speaker 1: brand new world in quantum uh science as well as 1066 01:06:01,160 --> 01:06:05,320 Speaker 1: just physical science. You may have seen the infamous picture 1067 01:06:05,600 --> 01:06:09,440 Speaker 1: of IBM spelling out its name and individual atoms that 1068 01:06:09,640 --> 01:06:13,920 Speaker 1: use lasers to position them. It's really pretty awesome. And 1069 01:06:13,960 --> 01:06:16,520 Speaker 1: by the late nineteen eighties Gould began to get royalties 1070 01:06:16,560 --> 01:06:20,600 Speaker 1: for his patents, so better late than never. In seven, 1071 01:06:20,840 --> 01:06:24,440 Speaker 1: Dr Stephen Truckle became the first doctor to use an 1072 01:06:24,440 --> 01:06:28,080 Speaker 1: ex semer laser to perform corrective surgery on a patient's eyes. 1073 01:06:28,840 --> 01:06:32,480 Speaker 1: This method was called the photo refractive care tectomy or 1074 01:06:32,600 --> 01:06:36,000 Speaker 1: pr K surgery. That would start a line of research 1075 01:06:36,040 --> 01:06:39,040 Speaker 1: and development in laser eye surgery in general, with lazic 1076 01:06:39,080 --> 01:06:43,960 Speaker 1: surgery debuting in ninete and I had lazy lazic surgery 1077 01:06:44,000 --> 01:06:47,800 Speaker 1: done just a few years ago. It corrected my vision. Uh. 1078 01:06:47,840 --> 01:06:50,240 Speaker 1: I talked about it on a podcast. Chris Pallette was 1079 01:06:50,240 --> 01:06:52,280 Speaker 1: on that one too, So you can do a search 1080 01:06:52,320 --> 01:06:55,240 Speaker 1: on tech stuffs archives and hear all about laser eye surgery. 1081 01:06:55,440 --> 01:06:57,440 Speaker 1: And I think if you listen carefully enough you can 1082 01:06:57,480 --> 01:07:02,160 Speaker 1: actually hear Chris Pallette turned green in the episode. He 1083 01:07:02,560 --> 01:07:07,680 Speaker 1: does a lot of unpleasant sounds because it was clear 1084 01:07:07,720 --> 01:07:10,640 Speaker 1: he was not comfortable in that episode. I might have 1085 01:07:10,680 --> 01:07:14,080 Speaker 1: taken a little extra glee from that. Now, skipping way 1086 01:07:14,080 --> 01:07:16,720 Speaker 1: ahead to two thousand three, that was when researchers from 1087 01:07:16,760 --> 01:07:20,600 Speaker 1: NASA demonstrated that you could power an aircraft using lasers. 1088 01:07:21,080 --> 01:07:25,800 Speaker 1: The aircraft in question weighed just threeleven grams, not kilograms, 1089 01:07:26,440 --> 01:07:29,680 Speaker 1: just grams. It had a balsa would frame and had 1090 01:07:29,680 --> 01:07:33,200 Speaker 1: a wingspan of one and a half meters. Net used 1091 01:07:33,200 --> 01:07:37,200 Speaker 1: an electric motor that was powered by a photovoltaic cell, 1092 01:07:37,400 --> 01:07:39,880 Speaker 1: so like a solar cell, but in this case it 1093 01:07:39,920 --> 01:07:44,840 Speaker 1: was specifically accepting light from this laser which was firing 1094 01:07:44,880 --> 01:07:47,560 Speaker 1: in an invisible spectrum, so you couldn't see the laser, 1095 01:07:47,960 --> 01:07:50,120 Speaker 1: but you can direct it at the cell that would 1096 01:07:50,120 --> 01:07:53,360 Speaker 1: provide the energy needed to convert it over into electricity 1097 01:07:53,640 --> 01:07:57,360 Speaker 1: and us propel the aircraft, which pretty cool. And today 1098 01:07:57,360 --> 01:07:59,240 Speaker 1: there are tons of uses of lasers, and some of 1099 01:07:59,240 --> 01:08:02,560 Speaker 1: them are released silly, like you know, they're being sold 1100 01:08:02,600 --> 01:08:05,480 Speaker 1: as cat toys and dog toys at this point, but 1101 01:08:05,560 --> 01:08:08,240 Speaker 1: some are really serious or things that are used in 1102 01:08:08,280 --> 01:08:12,040 Speaker 1: the medical field, for engineering, for industry, and we're looking 1103 01:08:12,080 --> 01:08:14,880 Speaker 1: at the possibility of even using them to propel spacecraft 1104 01:08:14,920 --> 01:08:17,520 Speaker 1: to other star systems, which is a really neat idea. 1105 01:08:17,920 --> 01:08:21,280 Speaker 1: This is based on the idea of the solar sail, 1106 01:08:22,080 --> 01:08:26,639 Speaker 1: where you have a spacecraft and it has a sale 1107 01:08:27,080 --> 01:08:33,360 Speaker 1: that you can direct light toward, and light has momentum. 1108 01:08:33,400 --> 01:08:37,120 Speaker 1: It's got relativistic momentum, So a photon does not have 1109 01:08:37,160 --> 01:08:40,240 Speaker 1: a lot of momentum by itself, but a stream of 1110 01:08:40,280 --> 01:08:44,240 Speaker 1: photons directed at a surface for long enough does have 1111 01:08:44,960 --> 01:08:47,720 Speaker 1: a physical push to it. And as it turns out, 1112 01:08:47,760 --> 01:08:52,360 Speaker 1: if you build very tiny spacecraft with a decent light sale, 1113 01:08:52,720 --> 01:08:55,640 Speaker 1: and you use a laser on Earth. You can continuously 1114 01:08:55,680 --> 01:08:59,840 Speaker 1: accelerate that spacecraft over time so that it reaches incre 1115 01:09:00,040 --> 01:09:03,360 Speaker 1: edible speeds. Now that acceleration is going to be at 1116 01:09:03,360 --> 01:09:07,360 Speaker 1: a low rate, so it doesn't speed up immediately, but 1117 01:09:07,439 --> 01:09:09,920 Speaker 1: it will over time get faster and faster and faster. 1118 01:09:10,000 --> 01:09:12,280 Speaker 1: And in fact, this is what some people are suggesting 1119 01:09:12,320 --> 01:09:17,040 Speaker 1: we do to send spacecraft to the nearest star system 1120 01:09:17,080 --> 01:09:19,800 Speaker 1: are the one that's nearest to our own That would 1121 01:09:19,800 --> 01:09:22,960 Speaker 1: be the Alpha Centauri system, and Proxima B would be 1122 01:09:23,320 --> 01:09:24,960 Speaker 1: the place we would really want to take a look at. 1123 01:09:25,120 --> 01:09:29,680 Speaker 1: That's the the planet around Proximates Centauri that's the closest 1124 01:09:29,880 --> 01:09:33,120 Speaker 1: to our solar system, that is the most earthlike in nature. 1125 01:09:34,600 --> 01:09:36,320 Speaker 1: And so there are some people saying, why don't we 1126 01:09:36,439 --> 01:09:40,960 Speaker 1: release swarms of tiny spacecraft using these sort of light sales, 1127 01:09:41,360 --> 01:09:45,160 Speaker 1: use lasers to direct them towards the Alpha Centauri system. 1128 01:09:45,200 --> 01:09:49,400 Speaker 1: And because of the incredible speeds they can reach, they 1129 01:09:49,400 --> 01:09:52,519 Speaker 1: can get to the Centauri system within about twenty years. 1130 01:09:53,520 --> 01:09:57,200 Speaker 1: That's incredible because the Centauri systems four light years away. 1131 01:09:57,520 --> 01:10:00,479 Speaker 1: That means it takes four years for light to get there, 1132 01:10:00,880 --> 01:10:04,599 Speaker 1: to hear, so to get there in twenty years using 1133 01:10:04,600 --> 01:10:08,479 Speaker 1: a physical spacecraft. You're moving at a really good clip. Now, 1134 01:10:08,560 --> 01:10:11,640 Speaker 1: granted at that speed, you're also just zooming by the 1135 01:10:11,640 --> 01:10:14,920 Speaker 1: Centauri system. You're not stopping for tea or anything, but 1136 01:10:15,040 --> 01:10:18,080 Speaker 1: still pretty cool idea that lasers could play an instrumental 1137 01:10:18,200 --> 01:10:20,840 Speaker 1: role in getting us to a different star system, or 1138 01:10:20,880 --> 01:10:23,559 Speaker 1: at least getting our eyes to a different star system. 1139 01:10:23,680 --> 01:10:27,800 Speaker 1: No humans would be traveling on those spacecraft. Well, that 1140 01:10:27,920 --> 01:10:30,919 Speaker 1: about wraps it up for this episode on Pupil Lasers. 1141 01:10:31,080 --> 01:10:33,719 Speaker 1: I hope you guys enjoyed it. I'll be talking about 1142 01:10:33,720 --> 01:10:36,720 Speaker 1: lots of other cool technology and upcoming episodes, so make 1143 01:10:36,760 --> 01:10:39,000 Speaker 1: sure you stay tuned to that. If you have any 1144 01:10:39,040 --> 01:10:42,479 Speaker 1: suggestions for future episodes, whether it's a topic or a 1145 01:10:42,600 --> 01:10:44,600 Speaker 1: guest I should have on the show, or someone you 1146 01:10:44,600 --> 01:10:46,400 Speaker 1: would love to have as a as a co host 1147 01:10:46,439 --> 01:10:48,559 Speaker 1: for an episode or two, let me know. Send me 1148 01:10:48,560 --> 01:10:51,519 Speaker 1: an email. The address is tech Stuff at how stuff 1149 01:10:51,520 --> 01:10:53,720 Speaker 1: works dot com, or you can drop me a line 1150 01:10:53,760 --> 01:10:56,880 Speaker 1: on social media on Facebook and Twitter. The show's handle 1151 01:10:57,040 --> 01:11:00,280 Speaker 1: is text stuff h s W as all as. You 1152 01:11:00,320 --> 01:11:04,320 Speaker 1: can also tune into twitch dot tv slash tech stuff 1153 01:11:04,360 --> 01:11:07,840 Speaker 1: on Wednesdays and Fridays to watch me stream the show live, 1154 01:11:08,240 --> 01:11:10,559 Speaker 1: where not only do you get to hear an episode early, 1155 01:11:10,960 --> 01:11:13,240 Speaker 1: you get to hear all the mistakes, you get to 1156 01:11:14,040 --> 01:11:17,639 Speaker 1: banter with me between segments, and you might even hear 1157 01:11:17,680 --> 01:11:20,480 Speaker 1: me tell horrible jokes at the end of an episode. 1158 01:11:20,720 --> 01:11:23,400 Speaker 1: So go to twitch dot tv slash tech stuff to 1159 01:11:23,479 --> 01:11:26,639 Speaker 1: see the schedule and join me there sometime. I'd love 1160 01:11:26,680 --> 01:11:29,680 Speaker 1: to see you until next time. I'll talk to you 1161 01:11:29,680 --> 01:11:38,559 Speaker 1: guys again, really soon. For more on this and thousands 1162 01:11:38,600 --> 01:11:51,040 Speaker 1: of other topics because it how stuff works, dot com