WEBVTT - How Lasers Work 0:00:00.280 --> 0:00:02.840 Brought to you by the reinvented two thousand twelve camera. 0:00:03.160 --> 0:00:08.920 It's ready. Are you get in touch with technology with 0:00:09.039 --> 0:00:18.040 tech Stuff from how stuff works dot com. Hello again, everyone, 0:00:18.040 --> 0:00:20.320 and welcome to tech stuff. My name is Chris Polette 0:00:20.360 --> 0:00:22.439 and I am an editor at how stuff works dot com. 0:00:22.840 --> 0:00:26.320 Sitting across from me again as usual, with another bright idea, 0:00:26.480 --> 0:00:30.040 is senior writer Jonathan Strickland. Back in the sixties, I 0:00:30.040 --> 0:00:32.960 had a weather changing machine that was, in essence, a 0:00:33.000 --> 0:00:39.280 sophisticated heat beam, which we called a laser. Using these lasers, 0:00:39.600 --> 0:00:41.880 we punch a hole in the protective layer around the Earth, 0:00:41.920 --> 0:00:46.560 which we scientists call the ozone layer. Slowly but surely, 0:00:46.640 --> 0:00:49.479 ultra violet rays would pour in, increasing the risk of 0:00:49.479 --> 0:00:51.920 skin cancer. That is, unless the world pays us a 0:00:51.960 --> 0:00:57.920 hefty ransom. Joy that was an easy one, you know, 0:00:58.000 --> 0:01:00.880 I Yeah, that's true. You know it's one because we 0:01:00.960 --> 0:01:03.600 sort of obfuscate as to what the topic of the 0:01:03.680 --> 0:01:05.760 show is going to be when we start, not just 0:01:05.920 --> 0:01:12.080 time yet you could probably read it before you even sure, 0:01:12.480 --> 0:01:14.880 and you just don't don't mean it. Yes, well, obviously 0:01:14.920 --> 0:01:18.400 we're gonna be talking about weather changing technology. Yes, now 0:01:18.520 --> 0:01:21.600 we're gonna talk about lasers, and this comes from a 0:01:21.600 --> 0:01:26.720 little Facebook feedback, you be, Nathan had this to say, 0:01:26.760 --> 0:01:29.280 how do lasers work? How does the lights stay in 0:01:29.280 --> 0:01:31.520 a straight line? What makes them different than a beam 0:01:31.560 --> 0:01:34.600 of light? Well, Nathan, we thought we would tackle this, 0:01:34.680 --> 0:01:37.399 and in order to explain lasers, we actually have to 0:01:37.720 --> 0:01:42.960 first talk about atoms. Indeed, you wouldn't necessarily believe it 0:01:43.000 --> 0:01:47.199 to be so um, you know, maybe not anyway, but yeah, 0:01:47.319 --> 0:01:52.040 the the science behind lasers is very very tiny on 0:01:52.080 --> 0:01:54.720 the atomic or molecular level, depending on what kind of 0:01:54.800 --> 0:01:57.080 laser you're talking about, most of the scientists don't top 0:01:57.080 --> 0:02:02.440 four ft ten. That's a lot at any rate, the 0:02:02.600 --> 0:02:06.560 right right to Jonathan, if you sists. So let's just 0:02:06.600 --> 0:02:09.280 do a little review on atomic science. This is this 0:02:09.320 --> 0:02:11.240 is from a high level. So anyone who has taken 0:02:11.240 --> 0:02:13.560 any kind of science classes where you've talked about atoms, 0:02:13.560 --> 0:02:15.360 this is going to be very familiar to you. But 0:02:15.480 --> 0:02:17.119 just just bear with us, because you have to start 0:02:17.200 --> 0:02:19.480 from somewhere right. Yeah, and and not all of our 0:02:19.480 --> 0:02:23.040 listeners are necessarily going to know this. So the atom 0:02:23.200 --> 0:02:26.880 is comprised of a nucleus, which is at least one 0:02:26.960 --> 0:02:29.800 proton and usually a pro some protons and some neutrons. 0:02:29.840 --> 0:02:33.760 Protons being the positively charged sub atomic particles, neutrons being 0:02:34.000 --> 0:02:37.320 having no charge, and then there are it's surrounded by 0:02:37.320 --> 0:02:40.440 a cloud of electrons, yes, and the electrons are the 0:02:40.480 --> 0:02:43.480 negatively charged particles. So you have with a with a 0:02:43.600 --> 0:02:47.880 standard atom in its elemental form, you have no net 0:02:48.080 --> 0:02:52.119 charge because the the protons and electrons cancel one another out. 0:02:52.880 --> 0:02:57.120 Now the electrons. Uh, it's this gets a little complicated. 0:02:57.160 --> 0:02:59.960 We have to kind of simplify things. Imagine that electra 0:03:00.040 --> 0:03:04.680 ons orbit the nucleus at different shells, Like there's a 0:03:04.720 --> 0:03:07.840 there's a shell that's a certain distance from the nucleus, 0:03:07.880 --> 0:03:10.640 and then there's another shell further out, and another shell 0:03:10.680 --> 0:03:14.280 further out, and only so many electrons can occupy each 0:03:14.400 --> 0:03:17.840 shell at a single time. Yeah, they really the orbit 0:03:17.880 --> 0:03:21.000 the nucleus in a way that uh, in which you know, 0:03:21.040 --> 0:03:25.440 for the more complex types of atoms, you you have 0:03:25.520 --> 0:03:28.399 some that are closer to the nucleus than others. They're 0:03:28.440 --> 0:03:31.160 just not room enough in that orbit for those other 0:03:31.280 --> 0:03:33.760 electrons to be. And it's funny because you think about 0:03:33.760 --> 0:03:35.600 it in a three dimensional sense, and it's far more 0:03:35.600 --> 0:03:38.520 complex than the diagrams we've used to have to make 0:03:38.520 --> 0:03:40.880 in chemistry class, right with the circles and the larger 0:03:40.920 --> 0:03:43.280 circles and the larger circles. But if you think about 0:03:43.280 --> 0:03:46.600 I mean, these electrons are negatively charged, right right, So 0:03:46.640 --> 0:03:49.760 that means that they repel one another like repels like. 0:03:50.240 --> 0:03:53.120 So that's why you can only have so many electrons 0:03:53.160 --> 0:03:56.920 within that physical space, because they're gonna be pushing against 0:03:57.000 --> 0:04:00.440 one another as they're rotating as the orbiting I shouldn't 0:04:00.440 --> 0:04:04.880 say rotating as they're orbiting the nucleus. M Now here's 0:04:04.920 --> 0:04:07.440 the interesting thing is that the if you if you 0:04:07.920 --> 0:04:12.600 inject energy into an atom, what's your what happens is 0:04:12.640 --> 0:04:16.120 that those electrons will elevate to a higher energy state, 0:04:16.200 --> 0:04:19.120 so they will actually move further away from the nucleus. 0:04:19.520 --> 0:04:22.320 If you, if you inject enough energy into an atom, 0:04:22.360 --> 0:04:25.600 it will lose its electrons, or at least some electrons. 0:04:25.640 --> 0:04:29.520 That's how we generate electricity. So but if you if 0:04:29.560 --> 0:04:31.760 you don't do that much, if you just generate enough 0:04:31.760 --> 0:04:34.040 where it's the electron has been pushed out to one 0:04:34.040 --> 0:04:37.400 of the outer energy levels, and then you then remove 0:04:37.480 --> 0:04:40.880 that that source of energy, the electron will naturally come 0:04:40.920 --> 0:04:45.760 back down to its ground energy state. But we know 0:04:45.839 --> 0:04:48.920 about the law of conservation of energy, right, you can't 0:04:49.040 --> 0:04:51.400 that energy that you injected into the atom. It has 0:04:51.480 --> 0:04:54.320 to come back somehow. Well, in this case, when the 0:04:54.360 --> 0:04:57.600 electron comes back down to its ground state, it emits 0:04:57.720 --> 0:05:00.919 a photon, which is a light particle. M hm. And 0:05:01.000 --> 0:05:03.680 you know who had this idea way back in the day, 0:05:03.760 --> 0:05:07.720 would it be Mr Albert Einstein? Yes, yes, uh you know, 0:05:07.760 --> 0:05:10.120 of course we have an article about lasers on how 0:05:10.120 --> 0:05:12.520 Stuff Works dot com. But I wanted to go, um 0:05:12.839 --> 0:05:14.839 see what Britannica had to say about it, because I 0:05:14.839 --> 0:05:18.640 thought that would be a good general explanation for lasers. UM. 0:05:18.680 --> 0:05:23.080 And it was Albert Einstein who in nineteen sixteen figured that, uh, 0:05:23.160 --> 0:05:26.960 you know, he he noticed that that adams could release 0:05:27.080 --> 0:05:32.080 light when they were stimulated by light. UM. And you 0:05:32.080 --> 0:05:36.919 know it was Rudolph Walter Leidenburg who actually saw it happen. 0:05:37.360 --> 0:05:40.080 He was he was doing some experiments UM. And for 0:05:40.120 --> 0:05:42.080 a while, this this phenomenon, it was just sort of 0:05:42.080 --> 0:05:45.159 a something that we knew. It wasn't anything that we 0:05:45.279 --> 0:05:48.000 did something with you, oh, let's go build some lasers. 0:05:48.080 --> 0:05:51.920 In fact, there's a natural phenomenon that happens, uh that 0:05:52.080 --> 0:05:54.200 you can you can observe if you're far enough to 0:05:54.240 --> 0:05:56.880 the north or to the south on the Earth, which 0:05:56.880 --> 0:05:59.359 are the northern and southern lights of the Aurora borealis 0:05:59.400 --> 0:06:02.680 and the Aurora astralis. And the reason for this is 0:06:02.720 --> 0:06:04.920 that you know, the Earth has a magnetic field, and 0:06:04.960 --> 0:06:08.039 that magnetic field converges at the north and south poles, 0:06:08.080 --> 0:06:11.960 the magnetic north and South poles and UH, and sometimes 0:06:12.000 --> 0:06:14.680 that magnetic field gets disrupted, for example, when there's a 0:06:14.720 --> 0:06:17.920 solar flare, and sometimes the solar flare will send enough 0:06:18.000 --> 0:06:21.480 energy to Earth that it it kind of uh will 0:06:22.520 --> 0:06:26.680 twist the magnetic field will realign earth magnetic field that 0:06:26.720 --> 0:06:29.359 tends to dump a lot of energy into the ionosphere, 0:06:29.760 --> 0:06:33.560 and the particles in the ionosphere they'll this is what happens. 0:06:33.560 --> 0:06:36.640 The electrons get elevated to a higher energy state when 0:06:37.040 --> 0:06:41.560 the atoms calm down, essentially they emit photons and we 0:06:41.560 --> 0:06:44.320 we can see that invisible light. And that's when you know, 0:06:44.360 --> 0:06:46.080 if you're at far off to the north and you 0:06:46.120 --> 0:06:49.039 look off and you see these bright flashing lights in 0:06:49.040 --> 0:06:52.880 the sky and they're all these pretty colors, that's what's happening. 0:06:52.920 --> 0:06:56.760 It's actually the same phenomenon that we use to to 0:06:57.120 --> 0:07:04.080 create a laser UM. So in more to laser history UM, 0:07:04.080 --> 0:07:08.960 it was Columbia University's Charles H. Towns who decided to 0:07:09.040 --> 0:07:14.120 try working on atoms at microwave frequencies UM and he 0:07:14.160 --> 0:07:16.880 actually demonstrated in nineteen fifty three that it could be done. 0:07:16.920 --> 0:07:20.360 Except he called his a mazer for microwave amplification by 0:07:20.360 --> 0:07:25.320 the stimulated emission of radiation UM, and he actually got 0:07:25.320 --> 0:07:29.200 the nineteen sixty four Nobel Price or physics UM. Also 0:07:30.080 --> 0:07:35.560 UH Alexander Prokarov and Nikolai Bessov of the PM Lebedev 0:07:35.680 --> 0:07:38.720 Physical Institute in Moscow, who also we're working on the 0:07:38.720 --> 0:07:42.000 problem independently, none of it when it seems weird that 0:07:42.080 --> 0:07:45.960 all these things happen simultaneously, Like we we talked about 0:07:46.520 --> 0:07:50.040 the development of television. How two different people are credited 0:07:50.040 --> 0:07:52.360 with the invention of television depending on whom you ask. 0:07:52.480 --> 0:07:55.800 Shout out to Philo. Yeah, it's just it's just funny 0:07:55.800 --> 0:07:57.880 that that UM, and this happens all the time in 0:07:58.040 --> 0:08:02.960 the development of calculus. But yeah, we weird. Way to 0:08:03.000 --> 0:08:05.720 go Newton, like, can we have a clear winner please? Anyway, 0:08:06.280 --> 0:08:08.400 I'm sorry, but yes, I was gonna say so, yes, 0:08:08.440 --> 0:08:11.520 you you were mentioning the maser that that also is 0:08:11.560 --> 0:08:13.960 something we should point out that laser itself is an 0:08:13.960 --> 0:08:20.640 acronym light amplification by stimulated emission of radiation. You can 0:08:20.640 --> 0:08:24.120 see why laser was picked over that. Yea, And uh, 0:08:24.280 --> 0:08:27.280 do you have who made the first true laser um? 0:08:27.320 --> 0:08:29.680 I do have the first the person who made the 0:08:29.680 --> 0:08:34.920 first true laser um. Well, if you're talking about Gordon Gould, 0:08:34.960 --> 0:08:37.040 that is Oh, that wasn't who I have, But go ahead. 0:08:37.200 --> 0:08:39.440 He is the person who actually got he called it 0:08:39.640 --> 0:08:42.839 the laser um. He's the person who filed for the patent. Now, 0:08:43.320 --> 0:08:45.880 if you're talking about Towns again, he was working with 0:08:46.240 --> 0:08:50.160 Arthur L. Shallow, who was his brother in law UM, 0:08:50.320 --> 0:08:52.840 and they were looking at the infrared light and visible 0:08:53.120 --> 0:08:59.480 light wavelengths. And in December they published a and an 0:08:59.480 --> 0:09:02.600 issue of Physical Review was published and their paper was 0:09:02.679 --> 0:09:06.840 in it. UM. But Gordon Gould actually had his patents 0:09:06.880 --> 0:09:09.520 granted in the nineteen seventies and he's the one who 0:09:09.559 --> 0:09:12.560 made most of the money off of it. Because masers 0:09:12.600 --> 0:09:16.000 had actually been used in atomic clocks and microwave amplifiers, 0:09:16.000 --> 0:09:18.719 but they really weren't using them for much else. And 0:09:18.840 --> 0:09:23.559 lasers which use a different wavelengths of light um there, 0:09:23.600 --> 0:09:26.600 you can use them in different applications, and that's why 0:09:26.840 --> 0:09:28.720 this was so profitable. Are those the people that you 0:09:28.760 --> 0:09:31.520 had in Actually, the one I have specifically was a 0:09:31.520 --> 0:09:34.679 fellow who in nineteen sixty built a laser out of 0:09:34.720 --> 0:09:39.800 a synthetic ruby. Ah, you're talking about THEO yeah, Teddy 0:09:40.320 --> 0:09:43.800 Theodore Mayman. Yes, and uh, that would be the fellow 0:09:43.840 --> 0:09:47.560 who created the first true laser using a synthetic ruby. 0:09:47.559 --> 0:09:49.880 Now right now that that's the kind of laser that 0:09:49.920 --> 0:09:52.520 I think of as being the modern the kind of 0:09:52.600 --> 0:09:55.160 laser were used today. Although he when I think it's 0:09:55.200 --> 0:09:58.280 kind of interesting, he used a photographer's flash, Yeah, as 0:09:58.280 --> 0:10:01.199 a source of stimulation for chromium atoms in a in 0:10:01.240 --> 0:10:05.280 a ruby crystal, synthetic ruby crystal. So when you when 0:10:05.280 --> 0:10:08.160 you're talking about creating a laser, the first step is 0:10:08.240 --> 0:10:11.040 you have to have some sort of medium that you 0:10:11.080 --> 0:10:14.160 are going to, uh, you're going to apply energy to 0:10:14.400 --> 0:10:17.200 in order to excite the atoms within that medium. And 0:10:17.200 --> 0:10:20.520 I understand that's called a game medium and also sometimes 0:10:20.559 --> 0:10:25.559 called a lazing medium. So yeah, and you the the 0:10:25.600 --> 0:10:29.120 process of pouring energy into this is called actually it's 0:10:29.120 --> 0:10:33.439 called pumping. You pump the lazing medium to generate photons. 0:10:34.040 --> 0:10:37.479 That's that. That's a verbie often associate with super soakers, 0:10:38.960 --> 0:10:44.760 I associated with nikes, these old air nikes. Um. But 0:10:44.880 --> 0:10:47.440 the uh yeah, so you what you do is you 0:10:47.480 --> 0:10:51.000 have to generate enough energy within this lazing medium so 0:10:51.040 --> 0:10:54.920 that you're starting to push the electrons into the higher 0:10:55.000 --> 0:10:58.520 orbits or the higher energy states, I should say. And 0:10:59.440 --> 0:11:02.280 what's interest thing is that if the once they the 0:11:02.640 --> 0:11:05.679 electrons start coming back down and photons are admitted. If 0:11:05.720 --> 0:11:08.800 you've if you've arranged the material the right way, the 0:11:08.840 --> 0:11:12.760 medium the right way, and you have it uh contained properly, 0:11:13.280 --> 0:11:17.840 those photons when they strike other atoms will excite the 0:11:17.920 --> 0:11:22.720 atoms they hit, which will then generate their own photons. So, UM, 0:11:22.760 --> 0:11:25.480 it's not self sustaining. It's not gonna stay that way forever. 0:11:25.520 --> 0:11:29.559 You're gonna lose energy eventually through various means. But that 0:11:29.559 --> 0:11:33.160 that helps you. That's why it's called stimulated emission of radiation. 0:11:33.679 --> 0:11:36.760 It's it's you stimulate the emission and then the process 0:11:36.800 --> 0:11:41.040 starts to help sustain itself. UM. Now, with a laser 0:11:41.120 --> 0:11:44.760 you typically happen to have mirrors on either side of 0:11:44.840 --> 0:11:49.400 the lasing medium. So um when the photons start to 0:11:50.320 --> 0:11:53.319 travel through the medium, And by the way, another interesting 0:11:53.360 --> 0:11:56.920 thing here is that when a photon hits another atom 0:11:57.000 --> 0:12:00.040 um and excites the electron, and then the electro and 0:12:00.120 --> 0:12:03.000 comes back down to its ground state and it emits 0:12:03.040 --> 0:12:06.440 another photon, that second photon is going to travel in 0:12:06.480 --> 0:12:09.559 the same direction as the first photon, the one that 0:12:09.640 --> 0:12:11.280 hit it the first time. So if you think about it, 0:12:11.320 --> 0:12:15.320 think of like a series of um of billiard balls 0:12:15.840 --> 0:12:21.280 rights right physics, and just imagine that you somehow manage 0:12:21.440 --> 0:12:24.920 to line up those billiard ball balls absolutely perfectly and 0:12:24.920 --> 0:12:28.120 and they hit exactly the right way, so that when 0:12:28.120 --> 0:12:30.559 the first billiard ball connects with a second, the second 0:12:30.559 --> 0:12:32.640 one continues to travel on the straight line from the 0:12:32.640 --> 0:12:35.680 first one hits the third, third one continues hit going 0:12:35.720 --> 0:12:38.400 a straight line, hits the fourth, and it just becomes 0:12:38.400 --> 0:12:42.000 this chain reaction. Now, because there's a mirror on either end, 0:12:42.520 --> 0:12:44.880 there's actually a complete mirror on one end and a 0:12:44.960 --> 0:12:47.880 partial mirror on the other. Um, the photons when they 0:12:47.960 --> 0:12:50.680 hit the end are reflected back into the medium, and 0:12:50.720 --> 0:12:53.719 then it continues to create these this flow of photons. 0:12:54.280 --> 0:12:57.719 Now that partial mirror on the other side allows some 0:12:57.800 --> 0:13:02.040 photons to pass through, right, and they're all traveling in 0:13:02.080 --> 0:13:07.000 that one specific direction. It's a very intense, uh, coherent 0:13:07.960 --> 0:13:10.360 part of a beam of light. Now, this is the 0:13:10.440 --> 0:13:13.960 light traveling in a straight direction that Nathan was Yes, Yes, 0:13:14.040 --> 0:13:17.080 this is it's coherence is the concept we're talking about here. 0:13:17.080 --> 0:13:20.360 It's it's organized, right, So every photon is moving in 0:13:20.400 --> 0:13:24.559 the same direction as opposed to a flashlight, which is diffuse. Right. 0:13:24.640 --> 0:13:27.000 That and for one thing that the flashlight, when the 0:13:27.000 --> 0:13:30.160 photons are emitted, they're emitted in a more random pattern. 0:13:30.520 --> 0:13:33.480 They're not directed like in a laser. And you may 0:13:33.520 --> 0:13:36.720 even also have a lens that will focus that beam further, 0:13:37.200 --> 0:13:42.680 depending upon what application you have in mind for this laser. 0:13:43.000 --> 0:13:46.599 Like a laser pointer doesn't need to to focus the 0:13:46.679 --> 0:13:49.600 laser in a really intense beam because you're using it 0:13:49.640 --> 0:13:51.240 just to point stuff out and you don't want to 0:13:51.280 --> 0:13:54.280 burn a hole through the wall. Right. Yeah, that's that's 0:13:54.320 --> 0:13:56.439 the type of laser that I own. I have a 0:13:57.040 --> 0:13:59.559 red laser at home that I used to h to 0:13:59.679 --> 0:14:03.280 drive my cats crazy, yes, um, which they very very 0:14:03.360 --> 0:14:05.439 much enjoy and it also doubles nicely as a laser 0:14:05.480 --> 0:14:09.120 pointer if you happen to need one. But that's um, 0:14:09.160 --> 0:14:11.840 you know, they're they're fairly inexpensive because they don't need 0:14:11.920 --> 0:14:18.600 a lot of um high end parts if you will. Um, yeah, 0:14:18.640 --> 0:14:22.280 it's and it really depends two on the type of laser. 0:14:22.400 --> 0:14:24.240 I mean, they're there are a lot of things that 0:14:24.280 --> 0:14:30.120 you can change, um about lasers to change a number 0:14:30.120 --> 0:14:33.080 of things like um, the size of the beam and 0:14:33.360 --> 0:14:35.280 the color, because it has a lot to do with 0:14:35.320 --> 0:14:37.520 the medium. Yeah, we should actually point that out. In fact, 0:14:37.520 --> 0:14:39.560 I'm glad you mentioned that because I forgot to say that. 0:14:40.000 --> 0:14:42.880 The other interesting thing about a laser is that they 0:14:42.880 --> 0:14:45.920 are monochromatic. They are all of a single color. Now 0:14:45.960 --> 0:14:48.120 that color may not even be within the spectrum of 0:14:48.160 --> 0:14:50.840 what we can view. It might be not not not 0:14:50.960 --> 0:14:53.880 with invisible light, because you can have ultra violet lasers, 0:14:53.960 --> 0:14:58.720 you can have infrared lasers. But the color is dependent 0:14:58.880 --> 0:15:02.840 mainly upon the the state, the energy state of the electrons, 0:15:03.400 --> 0:15:06.880 and a lot of that will depend upon what specific 0:15:07.520 --> 0:15:12.120 medium you are using as your lasing medium. Because the 0:15:13.200 --> 0:15:16.320 you know, different atoms have different number of electrons, so 0:15:16.400 --> 0:15:20.040 therefore the the state. The various energy states are going 0:15:20.040 --> 0:15:25.280 to be different depending upon which elements you're using. So um, Yeah. 0:15:25.320 --> 0:15:29.920 For example, a carbon dioxide laser is often used in 0:15:30.160 --> 0:15:36.600 cutting applications, and it's um, it's it's a it's got 0:15:36.600 --> 0:15:39.640 a very large wavelength. The wavelength that we were talking 0:15:39.640 --> 0:15:43.160 about earlier, of course, that's talking about how long the 0:15:43.440 --> 0:15:48.680 a particular peak and trough of Yeah, that would be 0:15:48.720 --> 0:15:52.480 a wave. Uh you know that that determines a lot 0:15:52.560 --> 0:15:56.840 of different properties of lasers. Red lasers tend to have 0:15:56.880 --> 0:16:01.200 a wavelength of around six and ninety four nanometers or gnometers, 0:16:01.640 --> 0:16:04.720 depending on how you prefer it. Um. And remember a 0:16:04.800 --> 0:16:08.480 nanometer is one billionth of a meter. It's tiny, tiny, tiny, 0:16:08.920 --> 0:16:12.560 still big compared to the atomic scale. In the atomic 0:16:12.560 --> 0:16:17.360 scale is about a tenth the size of the nanoscale. So, 0:16:19.320 --> 0:16:21.880 like we said, depending on the medium, that's what's going 0:16:21.920 --> 0:16:25.120 to determine kind of the wavelength and therefore the color 0:16:25.360 --> 0:16:28.960 of the laser. So if you're using something like argon 0:16:29.080 --> 0:16:31.680 fluoride for your laser is going to be in the 0:16:31.760 --> 0:16:36.160 ultraviolet range, which means the wavelength is around ter So 0:16:36.480 --> 0:16:39.600 that's a tiny, tiny wavelength. The carbon dioxide one is 0:16:39.640 --> 0:16:45.560 ten six hundred nanometers, so that's quite a long wavelength. 0:16:45.960 --> 0:16:49.000 And then the stuff that we can see like the 0:16:49.040 --> 0:16:53.680 typical red laser that might be a helium neon laser, 0:16:53.760 --> 0:16:58.240 that that's one that can produce a red color and 0:16:58.280 --> 0:17:03.720 that's around six and thirty three amnometers in wavelength. So uh, 0:17:03.960 --> 0:17:07.080 that's to me, that's a really interesting idea is the 0:17:07.119 --> 0:17:09.720 fact that you know, just by experimenting with different mediums 0:17:09.800 --> 0:17:14.080 or media I should say not mediums, Um, we've determined 0:17:14.119 --> 0:17:16.560 that you can create different colors of lasers and and 0:17:16.600 --> 0:17:19.600 depending and the lasers themselves have different properties that are 0:17:19.680 --> 0:17:24.600 valuable in various applications. Yep. Um. And it it's worth 0:17:24.760 --> 0:17:28.520 noting to um that you mean you could use gases, 0:17:28.560 --> 0:17:33.040 solids or liquids as a medium for for lasers, and 0:17:33.280 --> 0:17:36.800 most of the ones we use our gas, um liquids 0:17:36.840 --> 0:17:40.800 are are the least common from what I understand from 0:17:40.840 --> 0:17:44.959 my research. But UM, yeah, it's uh, it's funny because 0:17:45.320 --> 0:17:48.240 it really the color laser too. You might go on 0:17:48.400 --> 0:17:53.000 to uh shopping sites where they have geek toys and 0:17:53.119 --> 0:17:54.720 uh and look at them and go, well, you know, 0:17:54.760 --> 0:17:58.560 the laser laser pointers like five dollars for a red one, 0:17:58.920 --> 0:18:02.800 but it's ninety or a hundred fifty dollars for blue 0:18:02.960 --> 0:18:05.040 or violet or you know what, what is the deal 0:18:05.080 --> 0:18:08.879 with that? Well? Um, I think part of that is 0:18:08.920 --> 0:18:12.800 that some are easier to make than others. Um. Part 0:18:12.800 --> 0:18:16.000 of that is probably the medium to scarcity of the 0:18:16.040 --> 0:18:19.600 medium and part of its demand. Um. And I think 0:18:19.640 --> 0:18:23.040 part of it also is how cool they look and 0:18:23.080 --> 0:18:26.040 how new they are, because um, now the red lasers 0:18:26.480 --> 0:18:30.560 red laser pointers have been available for so long. Um, 0:18:30.600 --> 0:18:32.640 you know, they're pretty common. I mean you could get 0:18:32.680 --> 0:18:34.240 I I picked mine up as a matter of fact, 0:18:34.280 --> 0:18:37.360 in the grocery store in the pet section. Um. But yeah, 0:18:37.400 --> 0:18:39.200 if you want to, if you want to violate laser, 0:18:39.560 --> 0:18:42.640 they're harder to find. Um. Yeah, I haven't been out 0:18:42.680 --> 0:18:45.240 as long, and they're kind of expensive. Hear, Mace Window 0:18:45.320 --> 0:18:47.560 had to drop three Corelian Freighters in order to get 0:18:47.600 --> 0:18:51.080 his lightsaber. You know, I almost mentioned lightsabers and whether 0:18:51.160 --> 0:18:53.239 or not we were growing our own crystals or not 0:18:53.720 --> 0:18:55.760 for this, and then I thought, I'll wait and see 0:18:55.760 --> 0:18:58.040 if Jonathan mentions it. You can just listen to our 0:18:58.119 --> 0:19:00.159 lightsaber podcast if you want to. That was that was 0:19:00.200 --> 0:19:02.560 a fun one. But yeah, but yeah, it had these 0:19:02.600 --> 0:19:04.960 these are these wavelengths, these lasers and different wavelengths are 0:19:05.000 --> 0:19:07.320 great for different kinds of applications. True, because I know 0:19:07.359 --> 0:19:10.440 you you were, you know, talking about Blu ray players 0:19:10.840 --> 0:19:16.240 Blu ray versus DVD. Yeah, yeah, okay, so DVD players. Um, 0:19:16.280 --> 0:19:20.640 the old DVD players used or still us really red 0:19:20.720 --> 0:19:24.879 lasers to read information off of a DVD. And the 0:19:24.960 --> 0:19:28.240 way this basically works is think of the DVD. It's 0:19:28.280 --> 0:19:30.399 got a it's got a layer on the DVD that 0:19:30.480 --> 0:19:34.720 has information that's recorded and essentially little pits. These little 0:19:34.760 --> 0:19:37.879 pits are read as ones and zeros. What happens is 0:19:37.920 --> 0:19:41.520 a laser will hit the pit or the blank space, 0:19:41.760 --> 0:19:44.600 because that's also information. It's just saying it's a zero 0:19:44.720 --> 0:19:49.240 rather than one. Essentially, I'm oversimplifying. Yes, yes, it's it's complicated. 0:19:49.280 --> 0:19:52.359 But and there's a reflective surface that's beneath that layer. 0:19:53.000 --> 0:19:56.040 So the laser hits the pit or the smooth space 0:19:56.119 --> 0:20:00.280 hits the reflective surface, bounces back towards a cent sore. 0:20:01.040 --> 0:20:04.720 Sincere I'm talking about lack lasers and sin sores, I 0:20:04.720 --> 0:20:07.679 don't know what the heck's happened in me this morning, guys, anyway, 0:20:07.720 --> 0:20:10.120 So the laser hits the pit, hits the reflective service, 0:20:10.200 --> 0:20:12.840 bounces back hits the sensor. The sensor detects whether you 0:20:12.880 --> 0:20:15.520 know what kind of element was on the DVD. That 0:20:15.560 --> 0:20:19.760 gets translated into digital information, which then eventually becomes the 0:20:19.760 --> 0:20:23.719 picture on your television screen. So with a red laser, 0:20:24.480 --> 0:20:27.119 you remember, the red lasers wavelength is around six and 0:20:27.320 --> 0:20:31.120 thirty three ninometers, So there's a certain amount of information 0:20:31.160 --> 0:20:35.280 you could fit on a DVD single layer DVD UH 0:20:35.320 --> 0:20:39.000 that you cannot exceed because the red lasers only able 0:20:39.040 --> 0:20:42.199 to detect something of a size that its wavelength can 0:20:42.280 --> 0:20:45.119 hit and bounce back from. Like if the pits were smaller, 0:20:45.160 --> 0:20:47.400 the wavelength wouldn't even detect it because the wavelength would 0:20:47.400 --> 0:20:50.160 be larger than the the actual element it was trying 0:20:50.200 --> 0:20:54.399 to detect. Well, Blu ray players use a blue laser, 0:20:54.480 --> 0:20:58.520 and blue lasers have a a smaller wavelength, shorter wavelength, 0:20:59.359 --> 0:21:04.200 their wavelength around footers, So essentially you can cram more 0:21:04.240 --> 0:21:09.560 information onto a blu ray disc because the wavelength is smaller, 0:21:10.160 --> 0:21:14.359 and UH, you the path the pattern on the DVD 0:21:14.480 --> 0:21:18.480 if you will, well, I mean, the disc itself is 0:21:18.760 --> 0:21:20.800 doesn't have to be as large for the laser to 0:21:20.840 --> 0:21:23.120 read it, so you can pack more information on there 0:21:23.160 --> 0:21:25.159 because the blue lazer has no trouble reading it at 0:21:25.160 --> 0:21:27.680 a smaller size. Exactly. Yeah, if you if you want 0:21:27.680 --> 0:21:30.040 to think of it in h here's another weird way. 0:21:30.119 --> 0:21:32.720 Think of it like a wall that's covered in in 0:21:33.400 --> 0:21:36.199 in white and black dots. Alright, but the white and 0:21:36.200 --> 0:21:38.720 black dots are maybe like a six inches in diameter. 0:21:39.119 --> 0:21:42.040 So you're using a flashlight, and the flashlight is shooting 0:21:42.200 --> 0:21:44.560 is has a has a circle of about six inches 0:21:44.600 --> 0:21:46.880 in diameter from the distance that you're at the wall, 0:21:46.960 --> 0:21:50.600 and you you you count the number of dots as 0:21:50.640 --> 0:21:55.040 you swipe the flashlight left and right across the wall. Well, 0:21:55.080 --> 0:21:58.360 then let's say that you've got another wall that has 0:21:58.440 --> 0:22:01.240 dots that are two inches in diameter, and you've got 0:22:01.240 --> 0:22:03.920 a flashlight and you've got a light that's two inches 0:22:03.960 --> 0:22:05.960 in diameter. It's you're going to be able to count 0:22:06.160 --> 0:22:08.919 way more dots on that wall than you could with 0:22:08.960 --> 0:22:10.919 the ones that were six inches in diameter. That's the 0:22:10.960 --> 0:22:14.679 same concept here. So it's interesting to me that just 0:22:14.760 --> 0:22:17.920 by switching to a different kind of laser, we've been 0:22:17.960 --> 0:22:22.800 able to cram more information in a storage medium. It's 0:22:22.840 --> 0:22:28.880 a really neat idea. And we talked recently about light Peak, 0:22:29.119 --> 0:22:33.480 which is now called Thunderbolt, at least as far as 0:22:33.800 --> 0:22:39.640 Apple products because it's apparently got an exclusivity deal with Apple. Um. 0:22:39.680 --> 0:22:42.040 But you we talked about light Peak a couple of 0:22:42.560 --> 0:22:51.480 episodes ago, and light Peak uses um infrared Uh uh yeah, 0:22:51.600 --> 0:22:56.200 infrared lasers instead of visible spectrum lasers. But it's same 0:22:56.240 --> 0:22:58.320 sort of concept here is that it's using that to 0:22:58.840 --> 0:23:02.240 shoot information sation from a chip to a device or 0:23:02.720 --> 0:23:06.560 vice versa. Uh. The digital information gets translated into a 0:23:06.600 --> 0:23:09.879 series of flashes of this laser, which get picked up 0:23:09.880 --> 0:23:16.600 by another sensor and then transmitted back into digital information. Now, um, 0:23:16.720 --> 0:23:19.120 there's something else I wanted to talk about that's related 0:23:19.160 --> 0:23:22.320 but not exactly on topic, but it's it's very recent 0:23:22.400 --> 0:23:25.080 and it's really cool, so I thought I would mention it. 0:23:25.080 --> 0:23:28.679 It's okay with you? Please do have you heard about this? Uh? 0:23:28.720 --> 0:23:33.359 This article that was published in the February issue of Science. 0:23:34.640 --> 0:23:37.760 Is it about an anti laser? It is. I knew 0:23:37.760 --> 0:23:41.000