- [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.
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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)
