WEBVTT - Pew! Pew! Laser! 0:00:00.160 --> 0:00:07.280 Brought to you by Toyota. Let's go places. Welcome to 0:00:07.440 --> 0:00:15.480 Forward Thinking. He there, and welcome to Forward Thinking, the 0:00:15.600 --> 0:00:18.239 podcast that looks at the future and says, prepare the 0:00:18.320 --> 0:00:23.200 laser beam. I'm gonna use it tonight. I'm Jonathan and 0:00:23.239 --> 0:00:29.120 I'm Joe McCormick. So you know, on July two, fourteen, 0:00:29.760 --> 0:00:35.320 a certain someone a Charles Hart towns Uh turned years old, 0:00:36.120 --> 0:00:40.360 and which is an impressive all on its own right, 0:00:40.600 --> 0:00:43.640 but he happens to be the guy who invented the laser. 0:00:43.920 --> 0:00:46.839 That's right. He's Professor emeritus of physics at the University 0:00:46.840 --> 0:00:51.600 of California, Berkeley. He's only just now retiring, so he's 0:00:51.600 --> 0:00:56.240 actually closing down his office this summer. However, he has 0:00:56.280 --> 0:00:59.920 said that he plans to visit their Space Sciences Laboratory daily. 0:01:01.520 --> 0:01:04.760 Years old. Yes, and he he is credited as the 0:01:04.800 --> 0:01:07.520 inventor of the laser, although he did not build the 0:01:07.560 --> 0:01:10.440 first one. So to really we want to talk about 0:01:10.480 --> 0:01:12.240 lasers today, but we thought it'd be kind of cool 0:01:12.280 --> 0:01:15.360 to get first start with like a retrospective on the 0:01:15.400 --> 0:01:17.920 invention of the laser. So let us go into the 0:01:17.920 --> 0:01:21.440 future of the past. Yes, So onward into the past. 0:01:22.480 --> 0:01:26.480 First of all, here's his philosophy, Mr. Towns, Professor Towns 0:01:26.520 --> 0:01:29.959 is philosophy. Uh, I have a good time doing physics. 0:01:29.959 --> 0:01:33.600 It's not work, it's just fun, which is kind of awesome. 0:01:34.840 --> 0:01:39.160 I like that. I like that fun. Yes, physics, it's 0:01:39.160 --> 0:01:42.520 it's physical fun. No, it's physics fun. So anyway, the 0:01:42.560 --> 0:01:44.840 invention of lasers, So the story goes that Towns was 0:01:44.880 --> 0:01:48.280 sitting on a park bench way back in nineteen fifty one, 0:01:49.080 --> 0:01:52.480 and he was thinking about light, high frequency light, and 0:01:52.560 --> 0:01:57.360 how you might want to concentrate light into a beam 0:01:57.520 --> 0:02:01.680 that would be useful for multiple applications. And uh, he 0:02:01.760 --> 0:02:03.800 was thirty five years old at this time and a 0:02:03.800 --> 0:02:07.200 professor at Columbia University and a consultant for Bell tele 0:02:07.400 --> 0:02:12.680 Telephone Laboratories, one of the leading research and development institutions 0:02:12.720 --> 0:02:15.440 at the time. Obviously, lots of stuff came out of 0:02:15.480 --> 0:02:18.480 Bell Labs, including things like the transistor, you know, so 0:02:19.240 --> 0:02:21.040 lots of stuff going on at that time. He would 0:02:21.040 --> 0:02:23.840 had been using light to study the energy states of 0:02:23.960 --> 0:02:28.760 molecules um spectroscopy, so you know how we talk all 0:02:28.800 --> 0:02:33.960 about the relationship between atoms and photons that if you 0:02:34.040 --> 0:02:37.360 excite atoms, electrons move into an excited state, and when 0:02:37.400 --> 0:02:38.920 they come back to the ground state, they have to 0:02:38.960 --> 0:02:41.639 release that energy that they had taken on, and they 0:02:41.720 --> 0:02:44.520 do that in the form of a photon. So he 0:02:44.639 --> 0:02:47.519 knew that stimulating atoms with the right wavelength of light 0:02:47.720 --> 0:02:51.440 could make them admit that same wavelength. Actually, really we're 0:02:51.440 --> 0:02:55.160 telling wavelength of electromagnetic radiation, because when he first started 0:02:55.200 --> 0:02:57.560 working with this, he was working with microwaves, which have 0:02:57.600 --> 0:03:01.400 a longer wavelength than visible light, right, so he was 0:03:01.440 --> 0:03:03.640 looking at this. This was all based off a theory 0:03:04.480 --> 0:03:11.120 that had been um proposed by some physicist named Einstein 0:03:11.520 --> 0:03:14.760 something like that. Yeah, yeah, just just just Albert Albert 0:03:14.800 --> 0:03:17.399 good old Albert Einstein back in nineteen seventeen had said 0:03:17.880 --> 0:03:21.440 that you should be able to to uh, to see 0:03:21.480 --> 0:03:23.800 this in action if you were able to build the 0:03:23.919 --> 0:03:27.080 right set up. And so he had been thinking Towns 0:03:27.080 --> 0:03:31.000 had been thinking about how to actually make this physical reality. 0:03:31.480 --> 0:03:34.480 And the trick was that if you were to excite 0:03:34.520 --> 0:03:37.760 atoms of a gas, they tended to rush off in 0:03:37.840 --> 0:03:40.440 all different directions, and then you you lose the atoms 0:03:40.480 --> 0:03:43.240 that you're trying to excite to try and create more 0:03:43.280 --> 0:03:46.080 of whatever wavelength you're you're shooting at them. So if 0:03:46.120 --> 0:03:49.840 you were to shoot atoms of a gas with microwaves, 0:03:50.080 --> 0:03:52.080 they might omit microwaves, but at the same time they're 0:03:52.120 --> 0:03:55.440 all dashing off into other directions. You don't really amplify anything, right, 0:03:55.480 --> 0:03:56.920 So you want to find some kind of way to 0:03:56.960 --> 0:04:01.440 focus your energy exactly. So uh. He decided that the 0:04:01.520 --> 0:04:03.560 way to do this would to be to build a 0:04:03.560 --> 0:04:07.800 resonant chamber, essentially a kind of a little a little 0:04:07.920 --> 0:04:11.480 enclosed space that would hold onto this gas and allow 0:04:11.560 --> 0:04:16.760 the gas to continuously emit these different wavelengths and amplify 0:04:16.839 --> 0:04:19.760 whatever signal you were sending in. So you could pump 0:04:19.800 --> 0:04:24.600 the gas with an energy source like a microwave, stimulate 0:04:24.640 --> 0:04:27.600 the atoms, which would then start to emit their own microwaves, 0:04:27.600 --> 0:04:30.640 and have a very concentrated beam microwaves as a result, 0:04:31.279 --> 0:04:33.520 and it would be a very coherent burst. He called 0:04:33.560 --> 0:04:39.640 it microwave amplification by stimulated emission of radiation or MAZER, 0:04:41.680 --> 0:04:46.040 so acronym action there. Yeah. Uh. And in night he 0:04:46.360 --> 0:04:48.719 thought of a way that he might be able to 0:04:48.720 --> 0:04:52.640 achieve the same sort of outcome, but by using light 0:04:52.880 --> 0:04:56.080 instead of microwaves. So in this case it would be 0:04:56.160 --> 0:04:58.960 a laser, not a mazer, so it would be pretty 0:04:59.040 --> 0:05:01.480 much the same principle, but it would be shorter wavelengths. 0:05:01.480 --> 0:05:04.560 Shorter wavelengths, and he was thinking about using a socially. 0:05:04.640 --> 0:05:06.960 Think of it like a tube of gas. So you've 0:05:06.960 --> 0:05:09.600 got like a glass tube that contains gas inside it, 0:05:09.880 --> 0:05:12.200 and you have some mirrors on either end of the tube, 0:05:12.200 --> 0:05:16.039 and then you start, uh putting a certain wavelength of 0:05:16.120 --> 0:05:19.520 light into that tube, a very specific wavelength, whichever one 0:05:19.560 --> 0:05:21.680 it happens to be. And this is also one of 0:05:21.680 --> 0:05:24.760 those reasons why we started seeing red lasers before we 0:05:24.800 --> 0:05:28.839 saw any other colors of lasers. Those are the longer wavelengths. 0:05:29.480 --> 0:05:32.920 So you would use a very specific wavelength of light 0:05:33.040 --> 0:05:35.719 into this this chamber of gas. The mirrors would allow 0:05:35.800 --> 0:05:38.960 the light to reflect back and forth, continuing that stimulation. Now, 0:05:39.000 --> 0:05:42.480 he didn't actually build this yet. He just thought, well, 0:05:42.560 --> 0:05:44.680 Labs patented it. But no, he did not build it. 0:05:44.880 --> 0:05:46.760 No one, no one had built one. They had just 0:05:47.080 --> 0:05:49.520 he had come up with the idea. Bell Labs patents it, 0:05:49.839 --> 0:05:52.120 and the race was on. You had lots of different 0:05:52.120 --> 0:05:54.960 companies actually, all trying to build this at the same time. 0:05:55.520 --> 0:05:58.760 But it's interesting that the first person to build one 0:05:59.440 --> 0:06:02.159 wasn't working on behalf of one of these large companies. 0:06:02.600 --> 0:06:07.039 He had received a fifty thousand dollar budget from the 0:06:07.080 --> 0:06:10.800 research institute he was working with UH two over the 0:06:10.800 --> 0:06:13.360 course of I think nine months to build one of these. 0:06:13.360 --> 0:06:16.800 So the odds were stacked against him, and yet Theodore 0:06:16.960 --> 0:06:21.480 Harold Mayman in nineteen sixty built the first working laser. 0:06:21.560 --> 0:06:25.240 He used a ruby crystal, synthetic ruby crystal as the 0:06:25.320 --> 0:06:29.240 lasing medium. That's the active laser medium. And we could 0:06:29.400 --> 0:06:31.960 talk more about what that actually means, but that would 0:06:31.960 --> 0:06:36.640 require going into the physics of lasers, which is incredibly complicated. 0:06:36.760 --> 0:06:39.920 I think it's funny that we now can create verbs 0:06:40.000 --> 0:06:45.680 like lazing. Yeah. Yeah, it was originally an acronym. Nobody 0:06:45.720 --> 0:06:48.400 has the idea anymore that it's an acronym. Laser is 0:06:48.440 --> 0:06:51.240 just a lower case word. Yeah, yeah, it's just a 0:06:51.600 --> 0:06:53.920 it's just a name for a thing. It doesn't you know, 0:06:54.000 --> 0:06:56.160 unless you you really were to look into it, you 0:06:56.160 --> 0:07:00.520 wouldn't realize that those letters originally stood for individual words. 0:07:01.160 --> 0:07:05.200 So how are lasers used right now today? Like, if 0:07:05.240 --> 0:07:09.160 we wanted to talk about typical uses of lasers today, 0:07:09.279 --> 0:07:12.480 what are some of the examples we would see. Uh, well, 0:07:12.520 --> 0:07:15.760 we're still using them for spectroscopy, Yes, yes, we are. 0:07:15.920 --> 0:07:19.840 We use it to study the nature between radiated energy 0:07:19.880 --> 0:07:22.080 and matter, and and there are a bunch of different 0:07:22.080 --> 0:07:25.760 ways that lasers can help with this. But basically it 0:07:25.800 --> 0:07:29.680 turns out that this invention really can have a very 0:07:29.760 --> 0:07:32.520 precise wavelength, which is what you're looking for in this 0:07:32.600 --> 0:07:35.960 sort of thing, because a particular wavelength can interact very 0:07:36.000 --> 0:07:39.400 predictably with atoms and molecules and stuff like that. And 0:07:39.480 --> 0:07:43.520 so by bouncing that light around with atoms and molecules 0:07:43.520 --> 0:07:45.480 and watching what happens, you can kind of figure out 0:07:45.520 --> 0:07:47.800 what it is. Right, So maybe a laser can help 0:07:47.840 --> 0:07:50.160 you look at a sample of matter and and tell 0:07:50.200 --> 0:07:53.160 you what's inside that stuff is. Yeah, and we use 0:07:53.240 --> 0:07:56.360 this for all sorts of things, everything from chemistry labs 0:07:56.400 --> 0:08:02.400 to astronomy and other applications. Then there's a microscopy. Various 0:08:02.480 --> 0:08:07.119 techniques are used in microscopy with lasers to uh, they're 0:08:07.240 --> 0:08:11.080 very complicated. Essentially, you're talking about removing blur, getting really 0:08:11.120 --> 0:08:14.760 precise looks at things in ways that would require me 0:08:14.800 --> 0:08:19.160 to write a textbook to explain. Yeah, how about ledar, Yeah, 0:08:19.160 --> 0:08:22.240 it's another use of lasers that's very very much a 0:08:22.320 --> 0:08:25.760 popular one. We have an idea for an upcoming episode 0:08:25.760 --> 0:08:28.800 of Forward Thinking where ldar would play a fairly significant role. 0:08:28.840 --> 0:08:32.120 I think yes, yes, uh so. Lightar would be essentially 0:08:32.679 --> 0:08:37.640 a type of laser ranging sort of. It's like radar lasers, 0:08:37.720 --> 0:08:41.320 your basic laser ranging. It's really simple idea, and that 0:08:41.440 --> 0:08:43.640 simple idea is that you have a laser and a 0:08:43.720 --> 0:08:46.400 sensor that's all part of this one device, right, and 0:08:46.480 --> 0:08:48.800 you pointed at the thing that you're looking at, and 0:08:48.840 --> 0:08:51.200 you say, I wonder how far away that thing is, 0:08:51.960 --> 0:08:55.160 and you turn on the device, and the laser shoots 0:08:55.160 --> 0:08:59.240 out of the device, hits whatever the intended target is. 0:08:59.559 --> 0:09:02.000 Some of that light bounces back, the sensor picks it up, 0:09:02.200 --> 0:09:05.200 and by calculating how much time it took between the 0:09:05.280 --> 0:09:09.120 laser coing out and the the light that was reflected 0:09:09.120 --> 0:09:12.000 back being picked back up, you can determine how far 0:09:12.040 --> 0:09:14.240 away things are because you know what the speed of 0:09:14.360 --> 0:09:18.320 light is within you know certain parameter. Obviously light does 0:09:18.360 --> 0:09:22.360 not travel uh at the same speed through all media, 0:09:22.520 --> 0:09:25.679 but you it's it's it's to the point where you 0:09:26.120 --> 0:09:28.560 don't really need to split hairs unless you need to 0:09:28.559 --> 0:09:31.640 get down to like the nanometer precision level, in which 0:09:31.679 --> 0:09:35.360 case you're probably using some other methodology. Now we can 0:09:35.440 --> 0:09:37.840 use this to check out things like, um, how far 0:09:37.840 --> 0:09:41.200 away the Moon is, which you know is pretty cool. 0:09:41.280 --> 0:09:44.240 The reason we can do that is because some of 0:09:44.280 --> 0:09:46.199 the folks who went walking around on the surface of 0:09:46.240 --> 0:09:50.520 the Moon left some stuff behind, specifically garbage, you know, Well, 0:09:51.720 --> 0:09:56.200 so that too, but also retro retro reflector rays. Yeah. 0:09:56.240 --> 0:10:02.120 So yeah, just specific mirrors since garbage on purpose. Yeah. 0:10:02.520 --> 0:10:04.760 So one of the ways that we can prove that, 0:10:04.840 --> 0:10:06.840 in fact, people have been to the Moon is the 0:10:06.880 --> 0:10:09.320 fact that we can shine a laser on one of 0:10:09.360 --> 0:10:12.440 these and detect the light that comes back. Uh so 0:10:12.520 --> 0:10:15.840 it's not moon martians, just bouncing it back for us. No, 0:10:16.120 --> 0:10:21.320 not not lunar martians. The weirdest things. Didn't you have 0:10:21.440 --> 0:10:26.480 some horrible evil scientists shine lasers into your eyes? I 0:10:27.320 --> 0:10:29.920 had someone shining lasers into my eyes. But he wasn't 0:10:29.920 --> 0:10:34.000 horrible nor evil. He was actually quite kind and well 0:10:34.120 --> 0:10:37.560 he was very nice to me, although he did I 0:10:37.559 --> 0:10:39.319 will say he was nice to me, but he also 0:10:39.440 --> 0:10:42.720 held my eyeball down, sliced my cornea, lifted the flat 0:10:42.800 --> 0:10:46.680 back and then shined a laser into it, thus reshaping 0:10:47.120 --> 0:10:49.679 my eyeball so that I might see better. Well, but 0:10:49.720 --> 0:10:51.600 you would ask him to I did. I paid him 0:10:51.640 --> 0:10:53.640 for the for the for the privilege of having this 0:10:53.760 --> 0:10:56.439 done to me. We're talking, of course, about lazing, one 0:10:56.480 --> 0:11:00.320 of the many types of eye surgery that involves lasers. Yes, 0:11:00.720 --> 0:11:03.520 many types of surgery can use lasers as cutting tools. 0:11:03.559 --> 0:11:06.679 These days, the lasers can take the place of physical tools, 0:11:06.720 --> 0:11:10.360 mechanical tools, stuff that could introduce contamination. You know, if 0:11:10.360 --> 0:11:12.280 you're using light, then you don't have to worry about 0:11:12.600 --> 0:11:17.480 any any germs on the cutting device itself. Um So 0:11:18.280 --> 0:11:21.600 there there are a lot of different medical uses for lasers. 0:11:21.640 --> 0:11:25.280 We'll talk about some upcoming possible medical uses for lasers 0:11:25.320 --> 0:11:28.080 as well. Sure, and on a very much larger scale, 0:11:28.160 --> 0:11:30.920 you can use lasers for drilling and cutting into things 0:11:30.960 --> 0:11:33.920 other than Jonathan's eyeballs. Yeah, Like, let's say that you 0:11:33.960 --> 0:11:36.680 wanted to do something similar to cutting into Jonathan's eyeballs, 0:11:36.679 --> 0:11:39.040 except that the thing you wanted to cut into was steel. 0:11:39.520 --> 0:11:42.079 Then clearly the laser that works on my eye is 0:11:42.160 --> 0:11:44.200 probably not going to get you very far with this 0:11:44.480 --> 0:11:47.679 massive block of steel. I wouldn't imagine so, but I know, 0:11:48.000 --> 0:11:50.280 but I haven't tested your eyeballs to see whether they're 0:11:50.280 --> 0:11:55.360 made it. It's just assume, um for the moment, that 0:11:55.440 --> 0:11:58.679 we don't actually have to test any of this out. So, Yeah, 0:11:58.800 --> 0:12:01.559 you can actually find very high powered lasers that are 0:12:01.640 --> 0:12:06.000 used in precision cutting. Obviously, you could have a laser 0:12:06.040 --> 0:12:13.120 mounted onto a computerized electronic table or a robotic arm 0:12:13.200 --> 0:12:16.840 and and it will follow a very specific pathway as 0:12:16.920 --> 0:12:20.360 dictated by you using a computer program, and thus you 0:12:20.360 --> 0:12:25.280 can carve away things in a very very precise way. Also, 0:12:25.920 --> 0:12:29.760 military lots of military uses, right, I think this separates 0:12:29.880 --> 0:12:33.319 pretty cleanly into two categories, which is lasers that are 0:12:33.440 --> 0:12:36.240 used in some kind of James Bond death trap scenario 0:12:36.440 --> 0:12:39.720 and then lasers that are not used in those scenarios. 0:12:39.800 --> 0:12:43.439 So that's that's hardly the clean scientific way of defining that. Yeah, 0:12:43.520 --> 0:12:46.440 obviously you have things like laser sights, things that allow 0:12:46.640 --> 0:12:50.240 people to be more effective in aiming weaponry for example, 0:12:50.400 --> 0:12:54.920 or uh there are also again laser range finders, are 0:12:55.040 --> 0:12:57.880 lots of other detection devices, and then there are a 0:12:57.960 --> 0:13:00.960 lot of proposed but potential use as of lasers, either 0:13:01.120 --> 0:13:05.640 as a counter weapon, against things like missiles. I mean, 0:13:05.679 --> 0:13:08.920 there was, of course the entire Star Wars program that 0:13:09.040 --> 0:13:13.640 was proposed to allow a satellite based system to either 0:13:13.760 --> 0:13:18.840 fire missiles or lasers at incoming uh, you know, an 0:13:18.840 --> 0:13:24.560 incoming attack that would disarm them. Obviously that never happened, 0:13:24.600 --> 0:13:28.600 but that was a proposed military use for lasers. They 0:13:28.679 --> 0:13:32.320 got the idea from Nicola Tesla, right well, Nikola Tesla 0:13:32.400 --> 0:13:34.960 certainly had a very similar idea about being able to 0:13:35.000 --> 0:13:40.240 bring down airplanes. He was specifically talking about airplanes. Um, 0:13:40.280 --> 0:13:44.280 although that's an entirely different episode. And then we have 0:13:44.559 --> 0:13:48.600 you know, there are other like less weighty uses for lasers, 0:13:48.600 --> 0:13:50.800 things like laser pointers, like if you if you really 0:13:51.480 --> 0:13:56.680 really need two give give your cat, give your cat 0:13:56.760 --> 0:14:00.280 some some stimulation using a laser pointer to make cat 0:14:00.360 --> 0:14:03.040 run as fast as it possibly can into a wall 0:14:03.320 --> 0:14:06.840 is way up there into a wall. Or if you 0:14:06.880 --> 0:14:10.240 want to, yeah, if you want claw marks up your walls. 0:14:10.679 --> 0:14:12.920 Usually I could get a good satisfying thunk out of it. 0:14:13.000 --> 0:14:18.320 It was. Dogs are are also susceptible to both of 0:14:18.360 --> 0:14:20.160 my both of my dogs when I had them, they 0:14:20.200 --> 0:14:23.400 were both very much fans of chasing the laser pointer. 0:14:23.480 --> 0:14:26.880 In fact, one of them even knew where the laser 0:14:26.960 --> 0:14:29.280 was coming from, but that didn't bother him. He still 0:14:29.280 --> 0:14:32.200 wanted to play with He would look at me when 0:14:32.280 --> 0:14:35.320 when the laser would point, when the dot would move away, 0:14:35.360 --> 0:14:39.480 and he's like, hello, we're not done. Um, you were 0:14:39.520 --> 0:14:41.880 obviously not really putting forth nearly the same amount of 0:14:41.880 --> 0:14:44.160 effort I am, So I think we can keep playing. Hey, 0:14:44.200 --> 0:14:46.280 what about the Dark Side of the Moon laser show? 0:14:47.680 --> 0:14:50.800 Or or here in Atlanta. Of course, if you wanted to, 0:14:50.960 --> 0:14:53.440 you could take yourself out to the Stone Mountain Park 0:14:53.440 --> 0:14:56.840 and see the Stone Mountain Laser show or laser backgrounds 0:14:57.000 --> 0:15:04.160 in portrait photography. Okay, yeah, so obviously lots of uses 0:15:04.200 --> 0:15:06.680 today for lasers, but we really wanted to spend a 0:15:06.720 --> 0:15:10.480 lot of time talking about some emerging uses of lasers. 0:15:10.480 --> 0:15:14.120 Some of the the cutting edge uses, and not meaning 0:15:14.120 --> 0:15:17.800 cutting edge in the sense of actually cut cutting necessarily. 0:15:18.760 --> 0:15:21.640 One of them is to use lasers to make optical 0:15:22.680 --> 0:15:27.120 quote unquote cables out of air. Okay, I have seen 0:15:27.120 --> 0:15:29.000 this in our notes, but I do not understand it 0:15:29.040 --> 0:15:30.760 at all. So break break this one down, all right. 0:15:30.840 --> 0:15:33.720 So first, it helps to understand generally speaking, how a 0:15:33.760 --> 0:15:37.280 fiber optic cable works. So fiber optic cable is essentially 0:15:37.280 --> 0:15:39.280 think of it as a glass tube because that's pretty 0:15:39.360 --> 0:15:41.920 much what it is UH, and it's a glass tube 0:15:41.960 --> 0:15:44.720 that is more dense in the middle that is on 0:15:44.800 --> 0:15:48.960 the outside, like the outer edge. UH. That density actually 0:15:49.000 --> 0:15:52.640 allows light to pass through it pretty effectively, whereas the 0:15:52.680 --> 0:15:55.600 outer edge when the light starts to like if light 0:15:55.640 --> 0:15:59.200 tries to escape this tube, it gets reflected back into 0:15:59.240 --> 0:16:01.600 the core, so it continues down its path until it 0:16:01.600 --> 0:16:04.560 gets to wherever you want it to go. So typically 0:16:04.600 --> 0:16:08.880 with telecommunication systems, we use this to allow data to 0:16:08.920 --> 0:16:13.760 pass between different nodes, whether those are computers or telephone systems, whatever, whatever, 0:16:13.800 --> 0:16:19.440 we're using fiber optics for now. Using UH lasers to 0:16:19.520 --> 0:16:23.160 make optical cables quote unquote cables out of the air 0:16:23.640 --> 0:16:26.120 is a little different, but it uses the same principle. 0:16:26.640 --> 0:16:30.200 Researchers at the University of Maryland have been really pioneering 0:16:30.240 --> 0:16:33.800 this research and what they're doing is they're using UM 0:16:33.840 --> 0:16:39.200 they're using high powered UH lasers to create kind of 0:16:39.200 --> 0:16:41.560 a channel through the air. So if you just use 0:16:41.600 --> 0:16:43.640 a regular laser through the air and you're just trying 0:16:43.680 --> 0:16:46.400 to use it to to get some data about something 0:16:46.400 --> 0:16:51.360 like inspector scopy, then um, you might be uh suffering 0:16:51.400 --> 0:16:55.880 some problems at greater distances. Because light does disperse as 0:16:55.920 --> 0:16:59.600 it travels, you lose some of that focus the longer 0:16:59.640 --> 0:17:03.800 it So if you're using just a regular laser without 0:17:03.880 --> 0:17:08.760 any kind of of control over how that disperses, you 0:17:09.080 --> 0:17:13.000 lose precision over the course of you know, whatever distance 0:17:13.000 --> 0:17:15.160 you're talking about, and the greater the distance, the more 0:17:15.200 --> 0:17:19.240 precision you lose. So they were looking at a way 0:17:19.320 --> 0:17:22.040 of fixing that, and by using this high powered laser. 0:17:22.480 --> 0:17:26.600 Essentially they create a core of dense air that's then 0:17:26.680 --> 0:17:32.240 surrounded by a an expanding circumference of air that's lower density, 0:17:32.440 --> 0:17:35.960 so you've got a lower density uh surrounding a a 0:17:36.080 --> 0:17:38.760 high density core. That high density core acts like the 0:17:38.800 --> 0:17:42.040 core of a fiber optic cable, so light can travel. 0:17:42.040 --> 0:17:44.840 A laser can travel down that core, and whenever it 0:17:44.920 --> 0:17:48.119 encounters that lower density on the outer edge, it reflects 0:17:48.160 --> 0:17:52.399 back into that core. The whole thing lasts for a 0:17:52.520 --> 0:17:56.679 split second, a fraction of a second, but a fraction 0:17:56.680 --> 0:17:59.280 of a second is an eternity for a laser. Because 0:17:59.359 --> 0:18:01.000 lasers are travel ling at the speed of light, they 0:18:01.000 --> 0:18:03.680 are light, so you don't have to worry about something 0:18:03.760 --> 0:18:06.680 lasting only a fraction of a second. Because light that 0:18:06.960 --> 0:18:09.560 they're like, it seemed like it was forever to me 0:18:10.200 --> 0:18:12.520 um although they don't really say that because as far 0:18:12.560 --> 0:18:16.359 as we know, because they're not sentiented. So what you 0:18:16.359 --> 0:18:18.880 would do is you could set up a system where 0:18:18.920 --> 0:18:21.480 you have essentially two lasers. You have the high powered 0:18:21.520 --> 0:18:25.160 laser that creates this channel to whatever destination you're looking at, 0:18:25.720 --> 0:18:29.480 and then within a split second of it firing, a 0:18:29.520 --> 0:18:31.800 second laser, the one that you're actually using to measure 0:18:32.119 --> 0:18:35.639 whatever the target is, would fire and it would travel 0:18:35.680 --> 0:18:39.560 along this pathway created by the first laser. So you 0:18:39.560 --> 0:18:43.200 would have this more dedicated channel, and that would allow 0:18:43.240 --> 0:18:46.240 you to have that precision, to retain that precision that 0:18:46.320 --> 0:18:48.679 you would have as if it were traveling through fiber optic, 0:18:49.000 --> 0:18:51.800 and not have to worry about the the light getting 0:18:51.920 --> 0:18:55.680 less focused as it goes along. I've seen a similar 0:18:55.720 --> 0:18:59.359 technique to this used in in other science branches, and 0:18:59.400 --> 0:19:01.720 what I suspectus going on here is that the first 0:19:01.800 --> 0:19:04.560 laser is is heating the air in a very particular pattern, 0:19:04.720 --> 0:19:08.480 causing that pattern of density density difference and that's that's 0:19:08.520 --> 0:19:11.080 what's creating the channel more or less. Yeah, that's that's 0:19:11.200 --> 0:19:13.720 essentially what's happening. You can actually see. There was one 0:19:13.720 --> 0:19:15.560 example I saw where they were using four of these 0:19:15.600 --> 0:19:20.280 high powered lasers together and then the four expanding areas 0:19:20.320 --> 0:19:24.639 of low density air would converge in the center and 0:19:24.680 --> 0:19:27.680 that would become the channel. So that becomes even more crazy. 0:19:27.800 --> 0:19:29.800 So that's that's cool. I feel like my head just 0:19:30.520 --> 0:19:34.360 like Cronenberg style. But that's awesome. The whole point the 0:19:34.560 --> 0:19:37.960 researchers used it to analyze the air itself that was 0:19:38.000 --> 0:19:40.720 affected by this high powered laser. They found that the 0:19:40.760 --> 0:19:43.160 signal from their measurements was about one and a half 0:19:43.240 --> 0:19:46.399 time stronger than if they had not used a wave guide. 0:19:46.400 --> 0:19:49.080 That is that that channel, right, So if they had 0:19:49.200 --> 0:19:51.879 used just a regular laser and regular air they hadn't 0:19:52.000 --> 0:19:54.840 changed anything, it would have been one point five times 0:19:54.920 --> 0:19:57.919 weaker than the what they had experienced once they did 0:19:58.000 --> 0:20:00.280 use the wave guide. So that was pretty cool. And 0:20:00.640 --> 0:20:03.840 while that's not such a huge deal for a a 0:20:04.000 --> 0:20:07.840 short range analysis where they were talking like three feet, 0:20:08.400 --> 0:20:13.520 once you start getting to really more significant distances, one 0:20:13.560 --> 0:20:17.040 point five times improvement in signal strength is a huge deal, 0:20:17.880 --> 0:20:21.080 and so the U. S. Military is very interested in this, 0:20:21.200 --> 0:20:24.119 but so are a lot of research institutions. So it 0:20:24.200 --> 0:20:27.040 could be that we could see this used in upper 0:20:27.080 --> 0:20:32.280 atmosphere applications where obviously using something like fiber optics would 0:20:32.280 --> 0:20:36.800 be difficult, if not impossible, to do. So it's kind 0:20:36.840 --> 0:20:40.280 of cool that they're actually thinking about using lasers to 0:20:40.440 --> 0:20:43.040 change the air itself and just to act as this 0:20:43.160 --> 0:20:45.880 temporary fiber optic cable, like I said, within them, within 0:20:46.000 --> 0:20:49.919 less than a second, the effect disappears. So to us, 0:20:50.119 --> 0:20:52.720 we humans, we would never be able to detect this, 0:20:53.160 --> 0:20:55.399 you know, in any meaningful way without the use of 0:20:55.520 --> 0:20:59.040 very precise distrimentation. Yeah, so that was one that I 0:20:59.040 --> 0:21:01.280 thought was really super cool. Of course, there's another one 0:21:01.280 --> 0:21:04.200 that we've talked about before, right, uh, not on this show, 0:21:04.240 --> 0:21:06.399 but on our sister show, Tech Stuff. We did a 0:21:06.400 --> 0:21:09.960 whole episode back in early we've talked about on the 0:21:09.960 --> 0:21:16.680 show Beam Tractor Beams. That's that's right. I had forgotten completely. Well, 0:21:17.200 --> 0:21:20.600 Lauren and I do a lot of episodes about technical 0:21:20.640 --> 0:21:22.919 and scientific things, but this is one of those super 0:21:22.960 --> 0:21:26.919 awesome emerging uses of lasers. Yeah, and okay, not for 0:21:27.160 --> 0:21:29.639 entire spaceships the way that you might think of tractor 0:21:29.680 --> 0:21:32.600 beams being used, because a laser that beg would mostly 0:21:32.600 --> 0:21:35.800 just burn up a spaceship. But different types of laser 0:21:35.800 --> 0:21:38.840 beams can indeed beas to trap and manipulate and move 0:21:39.080 --> 0:21:42.880 small particles from cells to molecules to atoms. And since 0:21:42.920 --> 0:21:45.000 the last time we talked about it was a little 0:21:45.040 --> 0:21:47.280 bit over a year ago, I'll go through some of 0:21:47.359 --> 0:21:51.560 some of our favorites here. Um optical tweezers are are 0:21:51.600 --> 0:21:54.600 the first one, and these are made with Gaussian beams, 0:21:54.720 --> 0:21:56.840 which are just laser beams that are brighter in the 0:21:56.920 --> 0:21:59.760 center than they are at their edges. And if you 0:22:00.160 --> 0:22:03.959 focus the beam with optical microscopes, you can, um like, 0:22:04.040 --> 0:22:07.680 remove bacteria from a sample, or sort cells, or move 0:22:07.720 --> 0:22:11.800 medical particles, or manipulate DNA strands or alter cell membranes. 0:22:12.320 --> 0:22:16.679 And the idea of optical tweezers is that light has momentum. Okay, 0:22:16.760 --> 0:22:20.160 so when light hits an object, the object bends the light, 0:22:20.240 --> 0:22:23.920 which changes the light's momentum, and due to the law 0:22:24.000 --> 0:22:27.600 of conservation of momentum, the light will then push back 0:22:27.720 --> 0:22:32.560 on the object equally and oppositely. The Gauzian nature of 0:22:32.600 --> 0:22:35.360 the beam here is important because if the sample gets 0:22:35.400 --> 0:22:37.919 off center in the beam, the weaker light at the 0:22:38.000 --> 0:22:41.040 edges will be bending around the object and pushing it out, 0:22:41.359 --> 0:22:44.080 but the stronger light in the center will be bending 0:22:44.080 --> 0:22:47.360 around it and pushing it back in, and the stronger 0:22:47.400 --> 0:22:51.120 force wins. This is really incredible stuff. And and again 0:22:51.119 --> 0:22:53.560 it's one of those things where when you first think 0:22:53.600 --> 0:22:56.480 about when you think about our our normal experience with light, 0:22:56.840 --> 0:23:00.320 you don't think of light as having momentum necessarily. I mean, 0:23:00.359 --> 0:23:03.360 you don't think of it as having a force, right, 0:23:03.680 --> 0:23:06.560 especially since you think of photons is being massless. But 0:23:06.560 --> 0:23:10.119 they do have a relativistic mass, meaning that at least 0:23:10.280 --> 0:23:12.639 when you get down to the to the math level, 0:23:12.920 --> 0:23:15.120 you have to take into account the fact that they 0:23:15.160 --> 0:23:18.680 have this this mass that exists on a relativistic level, 0:23:18.720 --> 0:23:21.440