WEBVTT - How Lasers Work 0:00:01.480 --> 0:00:18.440 Welcome to Stuff you should know, a production of IHEARTRADIOW. 0:00:11.560 --> 0:00:14.360 And welcome to the podcast. I'm Josh, and there's Chuck 0:00:14.440 --> 0:00:17.759 and Jerry's here too. And she was making too many 0:00:17.840 --> 0:00:20.000 laser noises, so we asked her to please go on 0:00:20.160 --> 0:00:22.599 you because she did, and I assume she's still making 0:00:22.680 --> 0:00:24.680 laser noises. We just can't hear right now. 0:00:25.160 --> 0:00:26.360 You have a little attitude about it. 0:00:26.360 --> 0:00:30.800 Too, she did. I mean, I was really mean and kurt, 0:00:30.840 --> 0:00:32.760 but she didn't have to be that way back. 0:00:33.159 --> 0:00:37.680 Yeah, this is a one way street, right, it's. 0:00:37.560 --> 0:00:38.720 My way or the highway. 0:00:40.000 --> 0:00:43.040 You know, it's about time we did an episode on lasers. 0:00:44.720 --> 0:00:47.120 This seems like something that we would have tackled in 0:00:47.200 --> 0:00:51.560 those first formative in that first formative decade, and. 0:00:51.479 --> 0:00:53.280 I'm glad we didn't because I think it's good to 0:00:53.360 --> 0:00:59.120 still do like a traditional you know, how X works episode, 0:00:59.280 --> 0:01:03.000 we should do one, And how X works it depends 0:01:03.000 --> 0:01:04.840 on what kind of X you're talking about. 0:01:05.640 --> 0:01:07.880 Ruby used to give us an X when she was little, 0:01:08.040 --> 0:01:10.000 when she was like two years old. If she didn't 0:01:10.040 --> 0:01:12.560 like something, she would do her fingers as an X. 0:01:13.200 --> 0:01:15.280 And she just keeps getting cooler and cooler. 0:01:15.400 --> 0:01:17.200 She forgot that she lost that one along the way. 0:01:17.240 --> 0:01:18.759 I told her to bring that back. 0:01:19.120 --> 0:01:19.880 Yeah, that's a good one. 0:01:19.959 --> 0:01:20.760 Uncle Josh likes it. 0:01:21.360 --> 0:01:23.479 That's like talk to the hand, but way better. 0:01:23.560 --> 0:01:24.440 Yeah, exactly. 0:01:26.080 --> 0:01:30.120 All right, So we're talking lasers today, not necessarily X. 0:01:31.120 --> 0:01:34.440 Maybe we will do X someday. Let's find out, okay, 0:01:34.440 --> 0:01:36.360 And everybody knows what a laser is, right. 0:01:36.800 --> 0:01:38.520 Yeah, I mean I feel like it's one of the 0:01:38.560 --> 0:01:41.200 more like one of those acronyms like scuba that you 0:01:41.319 --> 0:01:45.000 learn when you're like on the playground. M hm. So 0:01:45.120 --> 0:01:50.040 in this case, it stands for light amplification by stimulated 0:01:50.120 --> 0:01:53.440 emission of radiation. And now that I know what a 0:01:53.520 --> 0:01:55.640 laser is and how it works, they kind of nailed 0:01:55.680 --> 0:01:57.480 it with that acronym they did. 0:01:58.000 --> 0:02:00.320 You you can totally forgive them for the B and 0:02:00.440 --> 0:02:03.320 the of because that's a world class acronym. 0:02:03.560 --> 0:02:10.120 Yeah, that would be lab sere if they included those 0:02:10.320 --> 0:02:11.400 lasers so much cooler. 0:02:12.160 --> 0:02:14.720 Lab se or doesn't. It doesn't have that same ring 0:02:14.760 --> 0:02:15.760 to it as laser. 0:02:15.880 --> 0:02:17.560 Throw me the lab se or gun. 0:02:18.680 --> 0:02:24.560 That someone would say. No. So, lasers are everywhere everybody, 0:02:24.600 --> 0:02:26.560 They're all around you. A lot of them are pointed 0:02:26.600 --> 0:02:29.720 at you right now, you just can't see them. But 0:02:30.440 --> 0:02:33.920 like a UPC code scanner at a supermarket checkout. They 0:02:33.919 --> 0:02:37.760 still have supermarkets, right, Oh yeah, that's right. Everyone goes 0:02:37.760 --> 0:02:40.160 in and empties all of their bank accounts into them 0:02:40.160 --> 0:02:43.720 every week to get suesstenates. Well, when you check out, 0:02:43.840 --> 0:02:48.960 boo boo boop like that, that's actually a laser being triggered. 0:02:49.000 --> 0:02:53.079 You're scanning your UPC code. So lasers are everywhere. They're 0:02:53.120 --> 0:02:56.280 at the supermarket. At least, that doesn't necessarily mean you 0:02:56.360 --> 0:02:58.960 understand them. I didn't understand them until we started to 0:02:59.000 --> 0:03:01.120 research this, did you know. 0:03:01.440 --> 0:03:04.480 And it's really not that hard to wrap your head around. 0:03:04.520 --> 0:03:07.120 Actually I was kind of dreading this. But Dave did 0:03:07.120 --> 0:03:09.000 a great job with this article, sort of like you 0:03:09.120 --> 0:03:12.720 here in the traditional sense, like you said, yep, And 0:03:12.840 --> 0:03:15.440 he does a good job initially by sort of laying 0:03:15.480 --> 0:03:18.320 the groundwork of regular light compared to a laser light. 0:03:18.919 --> 0:03:20.560 And I think that's a great way to start. 0:03:21.400 --> 0:03:23.120 Well, yeah, if we're going to talk about lasers, we 0:03:23.200 --> 0:03:25.240 really I mean, we're talking about light. We kind of 0:03:25.280 --> 0:03:27.800 need to go back a couple of steps and say, okay, 0:03:27.919 --> 0:03:30.679 there's different kinds of light, you know, like the light 0:03:30.720 --> 0:03:33.560 we think of as sunlight or a light bulb or 0:03:33.600 --> 0:03:36.360 something like that, what we would call generally white light 0:03:37.120 --> 0:03:40.280 is as a lot of people know, all of the 0:03:40.320 --> 0:03:43.840 colors of the spectrum, the visible light spectrum together coming 0:03:43.840 --> 0:03:45.839 together to form white light. 0:03:46.320 --> 0:03:50.320 That's right, many different wavelengths. But just like you know, 0:03:50.400 --> 0:03:53.440 elementary school science, when you get that prism and your 0:03:53.440 --> 0:03:55.680 little mind is blown, it's still kind of blows my mind. 0:03:55.680 --> 0:04:00.600 You scatter that light into its different wavelengths and it's 0:04:00.680 --> 0:04:02.960 the colors of the rainbow there. But and this is 0:04:03.000 --> 0:04:05.360 something that like I don't think I even realize this, 0:04:06.240 --> 0:04:09.320 even those different wavelengths, it's not a single wavelengths. It's 0:04:09.360 --> 0:04:14.000 still a spectrum of different wavelengths creating the red or 0:04:14.000 --> 0:04:16.599 the blue or the yellow or whatever. And that's kind 0:04:16.600 --> 0:04:21.840 of where we find ourselves, you know, departing in what 0:04:21.880 --> 0:04:23.120 a laser ends at being. 0:04:24.160 --> 0:04:27.520 Yeah, because so for example, the yellow band, what we 0:04:27.560 --> 0:04:31.159 see is yellow, and the visible spectrum occupies the five 0:04:31.240 --> 0:04:35.200 hundred and seventy nanimeter to five hundred and ninety nanimeter range. 0:04:35.240 --> 0:04:37.400 You show up below that, I think you've got what 0:04:37.800 --> 0:04:41.240 red orange, something like that. ROYGBIV, Yeah, I can't remember 0:04:42.080 --> 0:04:46.880 above that you've got blue Green, roy g Green, and 0:04:46.920 --> 0:04:50.680 those just have different wave links. They're all electromagnetic light. 0:04:51.160 --> 0:04:53.280 It's the same thing as a microwave. It's the same 0:04:53.279 --> 0:04:54.960 thing as a radio wave. It's the same thing as 0:04:54.960 --> 0:04:58.760 a gamma ray. It's just the different frequencies make them 0:04:58.839 --> 0:05:03.920 different kinds of energy what we call the visible spectrum. 0:05:04.040 --> 0:05:07.440 The point is is within all those different nanometer wavelengths, 0:05:07.480 --> 0:05:09.960 say from five to seventy to five ninety, there's different 0:05:10.240 --> 0:05:13.560 kinds of yellow. There's different shades of yellow right in 0:05:13.600 --> 0:05:16.799 there across that the spectrum within the spectrum, I guess. 0:05:16.920 --> 0:05:20.559 Yeah, spectrum within the spectrum. Also a great album title. 0:05:21.680 --> 0:05:24.280 That is a great album title, Jeszisch. Maybe you could 0:05:24.279 --> 0:05:27.119 have like a prism with a beam of light coming 0:05:27.160 --> 0:05:29.320 in and then a rainbow coming out the other side. 0:05:29.480 --> 0:05:31.279 Yeah, this is nineteen sixties for sure. 0:05:31.760 --> 0:05:34.000 Yeah, pyramid even is a prism. 0:05:34.160 --> 0:05:38.040 Yeah. With Isaac Kay's's head floating above it. 0:05:38.960 --> 0:05:41.640 I'm describing the Dark Side of the Moon album cover. 0:05:42.040 --> 0:05:42.880 I know it's just kidding. 0:05:43.520 --> 0:05:45.560 Okay, well you were really throwing me off, you were. 0:05:45.680 --> 0:05:47.320 That was some meta joking right there. 0:05:47.360 --> 0:05:49.480 I have a great pressing of Dark Side of the 0:05:49.480 --> 0:05:52.760 Moon by the way you do. Yeah, you know, I 0:05:52.920 --> 0:05:54.560 had a record press or a guy who does that 0:05:54.640 --> 0:05:56.440 for a living. I was hanging out with him in 0:05:56.440 --> 0:05:58.520 New York with our friend Joey Ciara and these two 0:05:58.600 --> 0:06:01.320 guys who did that, and he said, yeah, some pressings 0:06:01.320 --> 0:06:03.000 like it's done by a human, so you might have 0:06:03.120 --> 0:06:06.080 some records that just sound really awesome because it was 0:06:06.120 --> 0:06:08.599 well done. And I was like yeah, and they're you know, 0:06:08.640 --> 0:06:10.640 one hundred and eighty gram. He was like, that's all bunk, 0:06:10.720 --> 0:06:13.520 by the way. He's like, it just makes you feel 0:06:13.520 --> 0:06:15.159 better that it's heavier, and I was like, oh man, 0:06:15.240 --> 0:06:16.040 that's disappointing. 0:06:17.040 --> 0:06:19.599 I do like the heft of a eighty gram. 0:06:19.920 --> 0:06:22.200 Apparently, they said, is that's all just for you to 0:06:22.279 --> 0:06:24.440 make you think it is better because it's heavier. 0:06:25.160 --> 0:06:26.640 It's heavier, so it's worth more. 0:06:26.760 --> 0:06:30.080 All right. So back to lasers. What you just described 0:06:30.440 --> 0:06:34.400 very well, by the way, was regular light wavelength within 0:06:34.440 --> 0:06:37.240 the wavelength. If you talk about the differences of a 0:06:37.320 --> 0:06:39.840 laser light, you're talking about three main differences, in the 0:06:39.839 --> 0:06:43.080 first of which is that single wavelength it's monoc like 0:06:43.120 --> 0:06:46.600 truly monochromatic. That beam of light that a laser is 0:06:47.200 --> 0:06:50.320 or I guess you know, produces Well, no, it's what 0:06:50.360 --> 0:06:54.280 it is is is just a very it's a single wavelength, 0:06:54.360 --> 0:06:55.599 highly highly concentrated. 0:06:56.160 --> 0:06:59.559 Yeah, so rather than say a wavelength between five seventy 0:06:59.600 --> 0:07:02.400 and five for being yellow, this is a five hundred 0:07:02.400 --> 0:07:06.120 and seventy two nanometer wavelength that is that specific yellow. 0:07:06.240 --> 0:07:09.720 That's right, and it's it's not it's made up entirely 0:07:10.000 --> 0:07:14.240 of yellow light on the exact same wavelength. That is 0:07:14.320 --> 0:07:19.080 incredibly important. That's a huge, huge difference. Lasers don't occur naturally. 0:07:19.640 --> 0:07:22.480 We've figured out how to make them, and by we, 0:07:22.760 --> 0:07:24.200 I'm including myself in you. 0:07:24.640 --> 0:07:28.640 That's right. The second big difference between laser light and 0:07:28.680 --> 0:07:32.000 regular light is that it's coherent. So not only is 0:07:32.040 --> 0:07:35.400 it just a single wavelength, but the photons of the light, 0:07:35.480 --> 0:07:37.320 and we're going to talk about where they come into 0:07:37.320 --> 0:07:39.480 play here in a second. Thanks to mister Einstein or 0:07:39.480 --> 0:07:43.640 doctor Einstein, the photons are perfectly in phase with one another. 0:07:43.760 --> 0:07:46.520 So if you look at that wavelength, the peaks and 0:07:46.560 --> 0:07:48.600 the troughs are all perfectly in sync. 0:07:49.400 --> 0:07:52.200 Yeah, and not like they're following the same plane and 0:07:52.240 --> 0:07:54.360 they're just kind of in synct like that like, they're 0:07:54.440 --> 0:07:56.600 upright above each other, right below each other. They're not 0:07:56.720 --> 0:07:59.520 interfering with one another in any way whatsoever. 0:08:00.040 --> 0:08:00.440 That's right. 0:08:01.160 --> 0:08:04.119 And then the last one is that they're colimated, meaning 0:08:04.120 --> 0:08:07.080 they're all traveling in the exact same direction. 0:08:07.760 --> 0:08:10.400 Yeah, I mean that's important. I mean culimated sort of 0:08:10.400 --> 0:08:14.160 a fancy way of saying directional. But as we'll see, 0:08:14.160 --> 0:08:16.800 they all have to be traveling that same direction to 0:08:16.800 --> 0:08:18.200 pick up their little photon buddies. 0:08:18.720 --> 0:08:21.560 Yeah. So essentially what you've got is a very specific 0:08:21.640 --> 0:08:24.800 kind of the exact same kind of light, none of 0:08:24.800 --> 0:08:28.360 which are interfering with the other photons that are coming 0:08:28.360 --> 0:08:30.360 out of the laser, all of which are traveling in 0:08:30.400 --> 0:08:32.199 the same direction, so they do not get in one 0:08:32.200 --> 0:08:35.600 another's way, and they can be combined very very tightly. 0:08:36.000 --> 0:08:38.280 And that's essentially what a laser does. 0:08:38.679 --> 0:08:41.560 Yeah, for sure. And it all goes back to that 0:08:41.640 --> 0:08:46.920 acronym stimulated emission, the SE and laser. You can't make 0:08:46.960 --> 0:08:50.439 a laser without SE, that's true. You can't spell laser 0:08:50.440 --> 0:08:53.040 without SE, and you can't have a laser without stimulated emission. 0:08:53.520 --> 0:08:57.079 And our buddy Einstein is the guy who sort of 0:08:57.120 --> 0:08:59.480 laid the theoretical groundwork. He didn't go out and build 0:08:59.480 --> 0:09:02.319 a laser. That came later, but he laid the theoretical 0:09:02.400 --> 0:09:06.120 groundwork for all of this back in the ridiculously in 0:09:06.160 --> 0:09:07.360 the early nineteen hundreds. 0:09:08.760 --> 0:09:12.440 Yeah, so back in nineteen oh five, most people were like, 0:09:12.520 --> 0:09:16.079 light's a continuous wave, and by proxy, the universe is 0:09:16.160 --> 0:09:19.600 one smooth, continuous thing. In Einstein's like, I don't think 0:09:19.640 --> 0:09:22.360 that's true. I think if you zoom in far enough, 0:09:22.440 --> 0:09:24.880 close enough into the fabric of the universe, you're going 0:09:24.920 --> 0:09:28.440 to see it's actually made of discrete, little little things 0:09:28.840 --> 0:09:33.200 and call them pixels, right, And he's like, if that's true, 0:09:33.240 --> 0:09:37.480 then light can't be one continuous wave either. So I 0:09:37.559 --> 0:09:40.040 think they're actually made up of those little tiny packets 0:09:40.240 --> 0:09:43.439 that I'm going to call photons. And he turned out 0:09:43.440 --> 0:09:45.800 to be right. He had a great equation for it too. 0:09:45.920 --> 0:09:49.240 It's so elegantly simple. That's the thing about Einstein. He 0:09:49.240 --> 0:09:52.040 could come up with like three different things and could 0:09:52.040 --> 0:09:54.320 completely change our understanding of the universe. 0:09:54.440 --> 0:09:58.640 Yeah, for sure, this is the Planck Einstein, Einstein, what 0:09:58.880 --> 0:10:02.600 just happened? I was concentrating so heavily. I'm not saying Plank. 0:10:03.640 --> 0:10:05.600 I've heard Plank I think that's how most people say. 0:10:05.679 --> 0:10:07.600 Oh, I've always heard plank. 0:10:07.840 --> 0:10:09.959 Okay, I've heard both, but most of the people I've 0:10:10.000 --> 0:10:12.200 ever heard say plank. But I mean, I run in 0:10:12.240 --> 0:10:13.360 pretty low brow crowds. 0:10:14.120 --> 0:10:17.280 I think the probably the correctest plank, but most people 0:10:17.320 --> 0:10:18.160 do say plank. You're right. 0:10:18.640 --> 0:10:20.439 I like the way that you said it the first time. 0:10:20.480 --> 0:10:21.559 The plank Einstein. 0:10:21.600 --> 0:10:26.800 No, it says Einstein though. Yeah, the Plank Einstein relation, 0:10:28.400 --> 0:10:31.840 which is the energy beach photon is equal to its 0:10:31.840 --> 0:10:36.360 frequency times Plunk's constant e equals HF. 0:10:36.880 --> 0:10:39.880 Yeah, and all Plunk's constant is all it is. It's 0:10:39.920 --> 0:10:44.400 the smallest possible measurement of energy that anything can have 0:10:44.480 --> 0:10:49.440 on like the quantum level. Right, And so Einstein was like, Hey, 0:10:49.480 --> 0:10:51.280 I want to figure out how all this stuff kind 0:10:51.320 --> 0:10:55.120 of interacts because I know that photons interact with electrons. 0:10:55.160 --> 0:10:56.640 I'm just positive of it. 0:10:56.920 --> 0:10:57.120 Wow. 0:10:57.240 --> 0:11:01.440 And they were figured that's pretty good. They were figuring out. 0:11:01.760 --> 0:11:03.840 He was figuring out I think other people were at 0:11:03.880 --> 0:11:07.480 the same time that when you have sub atomic particles 0:11:07.520 --> 0:11:10.600 like an electron orbiting an atom, which if you go 0:11:10.679 --> 0:11:13.800 listen to our periodic Table episode, I think we did 0:11:13.800 --> 0:11:18.679 a pretty decent explanation of how you know that symbolism 0:11:18.760 --> 0:11:22.520 or that visualization of it is not very correct. But 0:11:22.679 --> 0:11:25.040 for all intents and purposes for this, let's say that 0:11:25.080 --> 0:11:28.920 these electrons orbit in different orbits around the atom, and 0:11:28.960 --> 0:11:32.559 when a photon hits it that orbit, that electron goes 0:11:32.679 --> 0:11:37.640 up in energy I think for like one hundred nanoseconds typically, Yeah, 0:11:37.679 --> 0:11:39.360 and then it says, okay, I want to get back 0:11:39.360 --> 0:11:41.680 to my resting state it's ground state, and it goes 0:11:41.760 --> 0:11:44.120 back to its previous orbital But when it does, it 0:11:44.160 --> 0:11:45.200 poops out a photon. 0:11:45.640 --> 0:11:47.839 You know what's funny? What as earlier when I was 0:11:47.880 --> 0:11:49.719 going over there in my head, I said, poops out 0:11:49.720 --> 0:11:50.160 of photon. 0:11:50.600 --> 0:11:52.920 Sure, I mean you and I we share a brain 0:11:53.360 --> 0:11:54.959 when it comes to toilet humor. 0:11:55.040 --> 0:11:58.480 Yeah, that's true. Yeah, that's exactly right. So an atom 0:11:58.559 --> 0:12:00.760 is going to absorb that energy, and it can do 0:12:00.800 --> 0:12:02.360 that in a lot of ways, but let's just say 0:12:02.360 --> 0:12:04.440 in this case, it's like some it gets heated up, 0:12:04.720 --> 0:12:08.280 you know, like literally heated up. Those electrons are going 0:12:08.320 --> 0:12:10.560 to jump around and get excited. But once they that 0:12:10.600 --> 0:12:12.600 makes it unstable. But it wants to be stable. So 0:12:12.600 --> 0:12:14.559 when it goes back to that state. You're right, it 0:12:14.600 --> 0:12:22.040 poops out that photon. Einstein saw this, called it spontaneous emission. Yeah, 0:12:22.080 --> 0:12:24.920 and this happens all the time all over the place 0:12:25.640 --> 0:12:29.040 in nature. These photons are getting pooped out all over 0:12:29.080 --> 0:12:31.360 the place. But Einstein was like, well, hey, if it 0:12:31.360 --> 0:12:34.840 happens all the time naturally, he theorized, maybe we can 0:12:35.440 --> 0:12:37.360 we can stimulate it to do this. Maybe we can 0:12:37.400 --> 0:12:39.280 make this happen and control that emission. 0:12:40.000 --> 0:12:43.079 Yeah, Because here's the thing, right, Like you say you 0:12:43.080 --> 0:12:46.439 have a photon that hits an atom and knocks an 0:12:46.440 --> 0:12:49.560 electron into the higher energy state, then that electron poops 0:12:49.600 --> 0:12:52.840 out a photon. Well, that electron is just absorbed the photon. 0:12:53.160 --> 0:12:55.080 So another way of looking at it is the photon 0:12:55.200 --> 0:12:59.320 essentially goes into the electron and comes back out the 0:12:59.360 --> 0:13:02.560 other side kind of, but there's only one photon ever, 0:13:02.640 --> 0:13:06.200 one gets absorbed, one's produced. What Einstein figured out is 0:13:06.240 --> 0:13:10.600 with stimulated emission, you can use a photon to create 0:13:10.640 --> 0:13:13.880 another photon without losing the first photon. And if you 0:13:13.920 --> 0:13:17.840 do that a bunch of times, buddy, you can have like, oh, 0:13:17.880 --> 0:13:19.800 like you could make a basket with your shirt and 0:13:19.840 --> 0:13:20.800 fill it with photons. 0:13:20.840 --> 0:13:23.600 If you do it, right, Yeah, I mean he realized 0:13:23.640 --> 0:13:26.520 that photons like to hang out with one another, so 0:13:26.880 --> 0:13:29.920 it doesn't take a lot to get them, you know, 0:13:30.000 --> 0:13:32.760 traveling in a direction and saying, hey, buddy, come with me, 0:13:33.360 --> 0:13:35.880 and it creates this sort of sort of like a snowball, 0:13:35.920 --> 0:13:39.360 like a cascading effect where if you can get them 0:13:39.520 --> 0:13:44.520 in an excited state and stimulate them and have them 0:13:44.520 --> 0:13:46.760 pick up other photons and have them all travel in 0:13:46.800 --> 0:13:53.080 the same direction, you're like halfway toward laser town pretty much. 0:13:53.320 --> 0:13:55.480 You can see the outskirts of town and the light 0:13:55.520 --> 0:13:56.520 shooting up in the sky. 0:13:56.640 --> 0:13:57.080 Yeah you can. 0:13:58.080 --> 0:14:02.280 So yeah, So that's stimulated emission. And the key here 0:14:02.559 --> 0:14:04.559 is you don't have to spend a photon to get 0:14:04.559 --> 0:14:08.200 a photon, right, You can excite the atom in other 0:14:08.240 --> 0:14:11.000 ways as long as it's already in its excited state. 0:14:11.000 --> 0:14:14.400 When the photon comes along, it's going to produce another photon. Now, 0:14:14.559 --> 0:14:18.000 for the purposes of lasers, what's really really important here 0:14:18.280 --> 0:14:21.520 is it is going to produce an exactly identical photon 0:14:21.560 --> 0:14:26.160 as the first one that passes by, right, traveling in 0:14:26.160 --> 0:14:29.360 the same direction, and it's not going to interfere with 0:14:29.400 --> 0:14:33.000 the first one. So they're cohesive, and they're collimated, and 0:14:33.040 --> 0:14:36.480 they're exactly the same. They're monochromatic, which, as we said before, 0:14:36.880 --> 0:14:39.000 those are the things you need for a laser. So 0:14:39.200 --> 0:14:43.000 Einstein figured out back in nineteen seventeen how to make 0:14:43.040 --> 0:14:45.760 a laser, and it was like, you, guys, figure it out. 0:14:45.800 --> 0:14:47.560 I'm going to think about some other stuff. 0:14:47.760 --> 0:14:49.880 Yeah. And if you say, well, wait a minute, I 0:14:49.880 --> 0:14:52.240 thought you said nineteen oh five, like it even took 0:14:52.240 --> 0:14:54.400 Ein Einstein a little while to get there, you know, 0:14:54.640 --> 0:14:56.600 that's right, took a little while. So should we take 0:14:56.600 --> 0:14:57.000 a break. 0:14:58.000 --> 0:14:59.760 Yeah, I feel like a break is imminent. 0:15:00.640 --> 0:15:24.360 We'll be right back with more lasers, all right. So 0:15:24.440 --> 0:15:28.880 when we left, Einstein did some great work kind of 0:15:28.960 --> 0:15:32.280 laying the groundwork, this theoretical foundation of a laser. And 0:15:32.320 --> 0:15:35.520 then he was like, guys, I like to think of 0:15:35.600 --> 0:15:37.240 things with my brain and say them out loud and 0:15:37.240 --> 0:15:40.960 write them on chalkboards. If you want to build this thing, fine, 0:15:41.640 --> 0:15:45.480 maybe slide me some cash. But I don't do that 0:15:45.560 --> 0:15:48.480 kind of work. So people did though, that followed in 0:15:48.520 --> 0:15:50.480 his footsteps, and in the nineteenth fifties it was a 0:15:50.480 --> 0:15:54.960 physicist named Charles Towns. He worked at Bell Labs and 0:15:55.280 --> 0:16:00.840 he was doing research on microwaves microwave radiation, and he 0:16:00.920 --> 0:16:04.000 was trying to He didn't know it yet, but he was. 0:16:04.160 --> 0:16:06.480 He was halfway to laser town because he was trying 0:16:06.520 --> 0:16:10.680 to find ways to concentrate a beam of microwaves. 0:16:10.720 --> 0:16:14.720 In this case, what's nuts is this guy figured it out. 0:16:14.800 --> 0:16:17.720 He just basically tinkered around and made his own version 0:16:17.800 --> 0:16:20.560 of a laser. But rather than using light, he used 0:16:20.640 --> 0:16:21.920 microwave beams. Right. 0:16:22.040 --> 0:16:23.320 Yeah, he built like a thing. 0:16:24.080 --> 0:16:27.320 Yeah, he just he used ammonia adams. He put him 0:16:27.320 --> 0:16:31.520 in a sealed chamber and he got them to essentially 0:16:31.840 --> 0:16:36.400 emit microwave radiation that he was able to concentrate into 0:16:36.440 --> 0:16:40.680 a beam. Right, So that cascading effect happened just like 0:16:40.760 --> 0:16:44.000 we discussed before, and essentially the only difference is it 0:16:44.040 --> 0:16:47.760 wasn't a light, it was a microwave beam. And to 0:16:47.840 --> 0:16:52.120 test it, he aimed it at the front pocket of 0:16:52.160 --> 0:16:55.200 a passing colleague, Percy Spencer, who happened to have a 0:16:55.280 --> 0:16:59.560 chocolate bar in the front pocket, and he melted it and 0:16:59.640 --> 0:17:02.480 Percy Spencer never forgave him because that was his favorite 0:17:02.480 --> 0:17:03.880 short sleeve, button down shirt. 0:17:04.359 --> 0:17:06.040 I think we talked about this, did we do one 0:17:06.119 --> 0:17:09.480 of microwaves. Yeah, okay, well that would be exactly where 0:17:09.520 --> 0:17:11.000 we talked about it then, probably. 0:17:10.920 --> 0:17:13.159 Yeah, and they weren't colleagues. I just made that part up. 0:17:13.200 --> 0:17:15.480 But that was a that was for you, buddy. 0:17:15.600 --> 0:17:17.680 Oh no, wait, there was a chocolate thing though, what right? 0:17:18.040 --> 0:17:21.919 Yeah, yeah, yeah, that happened. But separately, I think Spencer 0:17:21.960 --> 0:17:24.280 was in the presence of some microwave generator and his 0:17:24.400 --> 0:17:27.320 chocolate bar melted. And now that went on to invent microwaves. 0:17:27.560 --> 0:17:30.199 This thing was totally different. It's just yeah, it just 0:17:30.240 --> 0:17:31.920 brought Percy Spencer to mind. 0:17:31.960 --> 0:17:36.400 Yeah, I like it. So he literally called this a mazer, 0:17:37.400 --> 0:17:42.520 a microwave amplified stimulated emission of radiation. He teamed up 0:17:42.520 --> 0:17:45.120 with a guy. It was a colleague named Arthur Shallow, 0:17:45.960 --> 0:17:47.760 and he said, let me see if we can do 0:17:47.800 --> 0:17:50.400 the same thing with light, and we'll call it an 0:17:50.440 --> 0:17:54.800 optical maser. And everyone was like, buddy, it's right there 0:17:54.800 --> 0:17:58.320 in front of your face, like, come on, just get there. 0:17:59.040 --> 0:18:02.399 I think it was theor myman I like to call 0:18:02.520 --> 0:18:06.720 him my man who actually came up with the laser. 0:18:07.400 --> 0:18:11.040 He built the first functional laser in nineteen. 0:18:11.040 --> 0:18:12.560 Sixty and came up with a name. 0:18:13.400 --> 0:18:16.960 I think he did Okay. Up to this point, they 0:18:17.040 --> 0:18:21.000 were all theoretical and my man was the first one 0:18:21.040 --> 0:18:24.680 to actually build one, and he used a ruby crystal, 0:18:25.359 --> 0:18:28.560 which at the time I think had already been dismissed. 0:18:28.560 --> 0:18:31.040 People were like, you can't use that to make a laser. 0:18:31.080 --> 0:18:33.040 And he's like, let me try again, and he did 0:18:33.040 --> 0:18:35.920 some more calculations. He's like, the ruby's actually going to 0:18:35.960 --> 0:18:39.280 be great. So he used a pink ruby crystal as 0:18:39.320 --> 0:18:40.960 what's called the gain medium. 0:18:41.119 --> 0:18:44.120 Yeah, that's like the material lasing material that you would 0:18:44.200 --> 0:18:45.640 use exactly. 0:18:45.680 --> 0:18:48.440 That's where the atoms that you get excited are all stored. 0:18:48.760 --> 0:18:53.320 Yeah, So he surrounded that crystal with a with a flash. 0:18:53.400 --> 0:18:56.520 It was a coil shaped flash bulb. So that's that's 0:18:56.640 --> 0:18:58.280 going to be the thing that you know, the heat 0:18:58.359 --> 0:19:01.600 or whatever or the light that stimulates the initial reactions 0:19:02.080 --> 0:19:06.239 the pump. Sure, and then the two ends of that 0:19:06.280 --> 0:19:09.520 crystal were painted reflective silver. So everything is sort of 0:19:10.800 --> 0:19:13.440 kind of trapped in there together, encouraging all those photons 0:19:13.480 --> 0:19:16.119 to bounce around and get a little wild and create 0:19:16.200 --> 0:19:19.200 more photons and say, hey, you know we're doing something here, 0:19:19.240 --> 0:19:20.520 guys and all. 0:19:20.600 --> 0:19:22.840 Yeah, all of these photons came out at six hundred 0:19:22.840 --> 0:19:25.240 and ninety four nanometers, which I guess is the precise 0:19:25.280 --> 0:19:26.560 wavelength of ruby red. 0:19:26.680 --> 0:19:27.399 Yeah, I guess so. 0:19:28.160 --> 0:19:30.800 And he showed that like there, there, here's a laser. 0:19:30.920 --> 0:19:33.600 Check it out. Let me see your face. Basically, I 0:19:33.600 --> 0:19:36.240 think was how he showed it off right. He would 0:19:36.240 --> 0:19:37.760 just wave it in people's faces. 0:19:37.840 --> 0:19:38.800 That's why he's my man. 0:19:40.520 --> 0:19:43.360 So that was it. I mean, that was the first 0:19:43.440 --> 0:19:46.400 laser that and it was what you want to say, 0:19:46.480 --> 0:19:48.800 like it was as easy as that. Of course that's 0:19:48.880 --> 0:19:52.080 not easy, but the principle of it is kind of 0:19:52.480 --> 0:19:54.800 like you said, it's simple to understand, which is great. 0:19:55.280 --> 0:19:58.000 Like we did one on the breathalyzer, and it is 0:19:58.080 --> 0:20:03.360 so ridiculously complicated. It's more complicated than a laser by far. 0:20:03.840 --> 0:20:04.760 I hated that one. 0:20:05.040 --> 0:20:05.560 I did too. 0:20:05.600 --> 0:20:06.880 That was a long period of time ago. 0:20:07.359 --> 0:20:09.439 I remember we picked it, we started researching, and I 0:20:09.480 --> 0:20:09.840 was like. 0:20:10.119 --> 0:20:10.600 This sucks. 0:20:10.600 --> 0:20:13.359 Wait, why am I not understanding this? It was just 0:20:13.560 --> 0:20:16.400 so complex. Let's never talk about it again. 0:20:16.480 --> 0:20:18.480 I think we just wanted the explanation to be like 0:20:18.800 --> 0:20:21.920 blow into tube smells beer exactly. 0:20:22.040 --> 0:20:23.960 You just make a bunch of like drunk jokes. 0:20:24.080 --> 0:20:27.760 Exactly, all right, So that that was the first laser, 0:20:28.480 --> 0:20:30.919 Like you said, he use that ruby to begin with. 0:20:31.040 --> 0:20:33.359 But there are all sorts of gain mediums. There can 0:20:33.400 --> 0:20:37.280 be liquids, there can be gases, and we should probably 0:20:37.280 --> 0:20:41.080