How Lasers Work, with Neil deGrasse Tyson

Video Statistics and Information

Video
Captions Word Cloud
Reddit Comments
Captions
- [Neil] This video is sponsored by Storyblocks. - So when it comes to lasers, you ever think we'll be able to make them so that we can shoot 'em out of our eyes? - Chuck, you see too many movies. Just get real. - How's this for real? (lasers phase blasting) (upbeat remixed music) (air whooshes) - We've all heard about lasers. We know the word. Do you know it's an acronym? - Yes, I did know that. - Yes, then let me hear it. - Wait, how do you spell it? - Laser, L-A-S-E-R. - Oh, okay, light amplification by stimulated emission of radiation. - (claps) Bada-bing! - There you go. Or stimulation of radiation. That's sexy lasers. (sighs) Okay, maybe not. We go back to 1917. - (laughs) Okay. - Albert Einstein. - I love how you just ignored me. (laughs) - Albert Einstein. Little do most people know that he basically introduced the physics concept of a laser. - Whoa, wait a minute. Are you for real? - Yes! And he should've had a Nobel Prize for it. He should've got like eight Nobel Prizes. - Exactly. - He got one, but he should've gotten eight. - He's so great. - So one of them was writing down the equation that allows us to even know and understand that a laser can exist. - Wow. - Okay? - Wait a minute, so there were no lasers, and then he mathematically said, yo, check out this laser. - No, no. He wrote a research paper establishing the principle of the laser. The laser would take another 43 years before it got invented. - Oh, that is so dope. - That how ahead of the time, she was. - Okay, right. - Oh my god. - So the way it works is you have an atom and it has electrons. - Right. - And the electrons, if you excite the atom, can have an electron bump up to a higher level. Think of it, energy. Think of it as like rungs of a ladder or floors of an elevator in a building. Electrons can hang out in a higher energy. - At a higher level. So it's like deuces. I'm going out. - There you go. So now there it is. Now the electron doesn't stay there. It wants to, the whole system wants to de-excite. And depending on the energy level, depending on the atom, depending on the conditions, the electron can stay there a short amount of time or slightly longer before it de-excites. - Okay. - Okay, just, that's basic electron transitions in atoms. - There you go. - Basic. - It gets excited, and then it calms down. - De-excited, it calms down. - Right. - Correct, okay. And it does that all by itself. - Oh, nice. - Okay, so now watch. If you send light with exactly the amount of energy to allow an electron to go from here to there, it'll get absorbed. The electron will go up. Then when the electron de-excites, it send back out exactly that same photon. - Like a club that's reached capacity. - Two people in, - One person in, - Two people out. - One person out. Exactly. Would it be the same? (laughs) Look the same. This would have a photon with the same amount of energy - Right. - coming out. Now it turns out that the photon that excited this energy level, this is Einstein's brilliance, if you bath this set of atoms in those photons, those photons will not only excite the atom, they will actively de-excite the atom just by being in the bath. - Nice. - It's a spooky fact. - That's kind of the reverse of being in the bath with me. (laughs) I'm just saying. - So that's the spooky thing. That's the stimulated emission. - Right. So there's the electron. It's gonna de-excite itself on it's own time. - On it's own time. Right, but if you put it in a bath of these photons, it'll make it happen faster. - Right, so it goes up and it comes right back down, but that's all contrived by the bath of photons. - It'll make it come back faster. - Right, fast. - And by coming down, it emits another photon. - Right, so now. - So this builds. - Oh my god! - That's what I'm saying. - Yes! - That's what I'm saying. - Oh, this is so cool! - Oh, right, right, right. - Right! - Okay, so you create a cavity, a very special cavity with two reflective sides, okay, so that when the photon of light gets created, it can stay in there and go back and forth and get magnified by this phenomenon. As long as this medium has these kinds of atoms that'll respond to that photon. - Right, so you're exciting the atoms, but you're amplifying the excitement! Oh snap, dammit! That's amazing (laughs)! - And we just created the whole acronym. Light amplification by the stimulated emission of the radiation. - That is amazing! Wait a minute. He figured this out without being able to test it. - He had an understanding of light and atoms and photons and (claps) out come this calculation. It was a calculation. - Wow. - It was a calculation that that should happen. And sure enough it does. - And it didn't happen until 43 years later. - We didn't make a box to have that happen until the early 1960s. - Wow. - Right. And back then lasers were expensive, and they were rare. And come the late '60s, early '70s, you know who had a lot of lasers? - Goldfinger. - No, Goldfinger, I forgot about that. Goldfinger, he had a big diabolical, evil man laser. (laughs) - Exactly. Like the best villain line ever. - Wait, is that one where they, James Bond is strapped to a table, and the laser's coming right up his business? - You expect me to talk? (laughs) No, Mr. Bond, I expect you to die. - Was that the line? - That's what the line. - Dude. - That's a great line. - You scare me sometimes. (laugh together) You gotta get out more, you know. - It's true. - So that's a big old laser, okay. So now lasers are like impulse items at Kmart, right. I mean, they're not something that you need like license to get or find in a laboratory because they got cheaper, better. So now we have a low power household lasers. You have very high powers that are still used in laboratories and things. Anyhow, so I never leave home without lasers. - I do know that. - So have an assortment of them here. This is one. I got people who dope up my lasers. - Oh, really? - Up in the Bronx. You don't have people that do that? - No. - Okay, so this is particularly bright. So just look at, this is a dark shirt, okay. (screams) Oh, oh, oh, Jesus! (laughs) - So this is bright enough to. - I'm scared to look at it. - When I use this at night, because I'm a planetarium director, this beam will go 60 miles into the sky, and I can point out stars and constellations. - That is amazing. - Of course, it's dangerous for airplanes. - Well, yeah. - You'd never do that. - I'm pretty sure that's illegal. - No, I got the. - Yeah, you know people. I know, you know people. (laughs) - So that's that one. So a red, a little known fact, a red laser and a green laser of equal power, - Mm-hmm. - The green laser's brighter even though they have the same power. - Why? - Because your retina is two or three times more sensitive to green light than it is to red light. - Got you. - So the same brightness, energy brightness, the green will look brighter. So my two laser here are green 'cause I'm pointing out stars in the night sky. So I can use the same amount of energy you'd have in your red laser, but it'll be that much more visible to everyone assembled. So lasers had originally industrial applications. - Right. - But. Still, like what are you gonna do with a beam, have it. So clever people started saying, hey, we can do a skin peel. So depending on the frequency of light that the laser is, it can have different penetration depths of certain materials including your skin, right. - So you could actually figure out exactly how many layers of the dermis you can go down and then burn that off. - And burn that off. Because it's very high intensity light. And so a lot of energy focused in one place because of this cavity that builds the light and then the light comes out. So there's that. But I keep wondering if Einstein only knew that in 1917 this brilliant concept would be used for cosmetics, (laughs) for skin peeling. - Right, I don't think that. I make this. - I'm just wondering. I'm just wondering. So these are some of the applications of lasers. And of course the military. - Well, of course. - Yeah, you get a pumped up enough laser, and you wanna talk about star wars, you can go into orbit and aim it at the sensitive circuitry of an enemy or rogue satellite. People think in war you wanna blow stuff up. - No. - No, you just wanna disable. - Right, you can take it out. - Just take it out. So if there's some part of the hardware that's more sensitive than other parts, you hit a laser to it, it melts it, burns it, fries the circuit, the satellite's dead in the water. I got a couple more examples. - Okay. - Also in medicine. - Right. - So it turns out the hemoglobin, just blood cells, are highly absorbent in green light. So if you have a very intense green laser, you can actually cauterize an open wound - Nice. - by this method. Because that's the blood cells that you're trying to stop where ever they're going. You just can basically singe it. - Fuse them. - Basically you singe that. - It's kinda walled off. - Walled off, exactly. - A big, beautiful wall of flesh. (laughs) Go ahead. - Wall, dot, dot, dot, of flesh. (laughs) Okay. And you can have very high intensity lasers that are not just killing a cell or burning it but actually vaporizing it. So there's some lasers that are powerful enough to vaporize cancer cells. If you've identified a tumor or the like. So that gets us to, what else is there? What else are we using lasers for? - How about when you look inside to scan your food at the supermarket. - Oh, barcodes. - Barcodes. - Barcodes. That's just a barcode, right. So barcodes are just lines of different thickness, and actually they're lines that representing a series of numbers. You could type in those numbers if you wanted, and get the same information that's in the barcode. But the point is a laser does, boop, (snapping) it's got it, the price. It's built into the code. - All the numbers are there, boom. - It's all there. And you can get even more information if you make it two dimensional. 'Cause a barcode is just one dimension. - Right. - All right. It's all just lines of different thicknesses in one dimension. You can make a two dimensional barcode which is basically a QR code. - Oh, that's the little square - The square things. with the Roy shaft for the laser. (laughs) Tell me what you see, laser. I see my father never loved me. - So you know what would be cool if you had like a three dimensional storage of information like a holographic. So the 3D version of the QR. - Wow. 'Cause a QR is a 2D version of the barcode. - Right. That'd be an interesting way. You could store like boat loads of information in a three dimensional barcode. - I believe we call that Neil deGrass Tyson. - Oh, stop (laughs). So, Chuck, we done with lasers? - Yes. - Good. - As a matter of fact, I'd just like to take one of-- - No taking my lasers. - Okay, all right. - My lasers. - In that case, maybe I'll just the time to tell you guys about Storyblocks. Hey, do you know the key to making a professional looking video? It's Storyblocks. We even use it here at "StarTalk." - I didn't know that. - Yeah, as a matter of fact, you probably saw some of their clips in this video. - Oh, okay. - Yeah. So Storyblocks gives you studio quality stock video without blowing up your budget. You get unlimited downloads of anything in their video member library, including 4K footage, After Effects templates, motion backgrounds, and more when you sign up for the unlimited video plan. I guarantee you it's much easier and cheaper to find the video you need on Storyblocks than it is to make it yourself. And, really, how you gonna get that video, anyway? Suppose you need the perfect aerial shot of the Statue of Liberty, what're you gonna do? Go ahead and get a helicopter, fly around the Statue of Liberty until you get the perfect shot. Find somebody that can edit that for you. Fly over restricted air. You get what I'm saying! - I get the point. - You get the, okay. (laughing together) Check out the link in the description to learn more about Storyblocks video. That's storyblocks.com/startalk. - And as always, keep looking up. (upbeat remixed music)
Info
Channel: StarTalk
Views: 479,711
Rating: 4.9370298 out of 5
Keywords: Albert Einstein, StarTalk, Neil deGrasse Tyson, Chuck Nice, Lasers, science explainer, goldfinger, electrons, photons, how do lasers work, explainer, neil degrasse tyson explains, neil degrasse tyson laser, chuck nice neil degrasse tyson, laser vision, james bond, sci fi, science podcast, space podcast, astronomy podcast, space, science, astronomy, astrophysics, einstein, physics, light, particles, atoms, atomic, accessory to war, laser uses
Id: t9jtGHXgQvw
Channel Id: undefined
Length: 12min 5sec (725 seconds)
Published: Thu Oct 31 2019
Related Videos
Note
Please note that this website is currently a work in progress! Lots of interesting data and statistics to come.