Speaker 1: Brought to you by the reinvented two thousand twelve camera.
Speaker 1: It's ready. Are you get in touch with technology with
Speaker 1: tech Stuff from how stuff works dot com. Hello again, everyone,
Speaker 1: and welcome to tech stuff. My name is Chris Polette
Speaker 1: and I am an editor at how stuff works dot com.
Speaker 1: Sitting across from me again as usual, with another bright idea,
Speaker 1: is senior writer Jonathan Strickland. Back in the sixties, I
Speaker 1: had a weather changing machine that was, in essence, a
Speaker 1: sophisticated heat beam, which we called a laser. Using these lasers,
Speaker 1: we punch a hole in the protective layer around the Earth,
Speaker 1: which we scientists call the ozone layer. Slowly but surely,
Speaker 1: ultra violet rays would pour in, increasing the risk of
Speaker 1: skin cancer. That is, unless the world pays us a
Speaker 1: hefty ransom. Joy that was an easy one, you know,
Speaker 1: I Yeah, that's true. You know it's one because we
Speaker 1: sort of obfuscate as to what the topic of the
Speaker 1: show is going to be when we start, not just
Speaker 1: time yet you could probably read it before you even sure,
Speaker 1: and you just don't don't mean it. Yes, well, obviously
Speaker 1: we're gonna be talking about weather changing technology. Yes, now
Speaker 1: we're gonna talk about lasers, and this comes from a
Speaker 1: little Facebook feedback, you be, Nathan had this to say,
Speaker 1: how do lasers work? How does the lights stay in
Speaker 1: a straight line? What makes them different than a beam
Speaker 1: of light? Well, Nathan, we thought we would tackle this,
Speaker 1: and in order to explain lasers, we actually have to
Speaker 1: first talk about atoms. Indeed, you wouldn't necessarily believe it
Speaker 1: to be so um, you know, maybe not anyway, but yeah,
Speaker 1: the the science behind lasers is very very tiny on
Speaker 1: the atomic or molecular level, depending on what kind of
Speaker 1: laser you're talking about, most of the scientists don't top
Speaker 1: four ft ten. That's a lot at any rate, the
Speaker 1: right right to Jonathan, if you sists. So let's just
Speaker 1: do a little review on atomic science. This is this
Speaker 1: is from a high level. So anyone who has taken
Speaker 1: any kind of science classes where you've talked about atoms,
Speaker 1: this is going to be very familiar to you. But
Speaker 1: just just bear with us, because you have to start
Speaker 1: from somewhere right. Yeah, and and not all of our
Speaker 1: listeners are necessarily going to know this. So the atom
Speaker 1: is comprised of a nucleus, which is at least one
Speaker 1: proton and usually a pro some protons and some neutrons.
Speaker 1: Protons being the positively charged sub atomic particles, neutrons being
Speaker 1: having no charge, and then there are it's surrounded by
Speaker 1: a cloud of electrons, yes, and the electrons are the
Speaker 1: negatively charged particles. So you have with a with a
Speaker 1: standard atom in its elemental form, you have no net
Speaker 1: charge because the the protons and electrons cancel one another out.
Speaker 1: Now the electrons. Uh, it's this gets a little complicated.
Speaker 1: We have to kind of simplify things. Imagine that electra
Speaker 1: ons orbit the nucleus at different shells, Like there's a
Speaker 1: there's a shell that's a certain distance from the nucleus,
Speaker 1: and then there's another shell further out, and another shell
Speaker 1: further out, and only so many electrons can occupy each
Speaker 1: shell at a single time. Yeah, they really the orbit
Speaker 1: the nucleus in a way that uh, in which you know,
Speaker 1: for the more complex types of atoms, you you have
Speaker 1: some that are closer to the nucleus than others. They're
Speaker 1: just not room enough in that orbit for those other
Speaker 1: electrons to be. And it's funny because you think about
Speaker 1: it in a three dimensional sense, and it's far more
Speaker 1: complex than the diagrams we've used to have to make
Speaker 1: in chemistry class, right with the circles and the larger
Speaker 1: circles and the larger circles. But if you think about
Speaker 1: I mean, these electrons are negatively charged, right right, So
Speaker 1: that means that they repel one another like repels like.
Speaker 1: So that's why you can only have so many electrons
Speaker 1: within that physical space, because they're gonna be pushing against
Speaker 1: one another as they're rotating as the orbiting I shouldn't
Speaker 1: say rotating as they're orbiting the nucleus. M Now here's
Speaker 1: the interesting thing is that the if you if you
Speaker 1: inject energy into an atom, what's your what happens is
Speaker 1: that those electrons will elevate to a higher energy state,
Speaker 1: so they will actually move further away from the nucleus.
Speaker 1: If you, if you inject enough energy into an atom,
Speaker 1: it will lose its electrons, or at least some electrons.
Speaker 1: That's how we generate electricity. So but if you if
Speaker 1: you don't do that much, if you just generate enough
Speaker 1: where it's the electron has been pushed out to one
Speaker 1: of the outer energy levels, and then you then remove
Speaker 1: that that source of energy, the electron will naturally come
Speaker 1: back down to its ground energy state. But we know
Speaker 1: about the law of conservation of energy, right, you can't
Speaker 1: that energy that you injected into the atom. It has
Speaker 1: to come back somehow. Well, in this case, when the
Speaker 1: electron comes back down to its ground state, it emits
Speaker 1: a photon, which is a light particle. M hm. And
Speaker 1: you know who had this idea way back in the day,
Speaker 1: would it be Mr Albert Einstein? Yes, yes, uh you know,
Speaker 1: of course we have an article about lasers on how
Speaker 1: Stuff Works dot com. But I wanted to go, um
Speaker 1: see what Britannica had to say about it, because I
Speaker 1: thought that would be a good general explanation for lasers. UM.
Speaker 1: And it was Albert Einstein who in nineteen sixteen figured that, uh,
Speaker 1: you know, he he noticed that that adams could release
Speaker 1: light when they were stimulated by light. UM. And you
Speaker 1: know it was Rudolph Walter Leidenburg who actually saw it happen.
Speaker 1: He was he was doing some experiments UM. And for
Speaker 1: a while, this this phenomenon, it was just sort of
Speaker 1: a something that we knew. It wasn't anything that we
Speaker 1: did something with you, oh, let's go build some lasers.
Speaker 1: In fact, there's a natural phenomenon that happens, uh that
Speaker 1: you can you can observe if you're far enough to
Speaker 1: the north or to the south on the Earth, which
Speaker 1: are the northern and southern lights of the Aurora borealis
Speaker 1: and the Aurora astralis. And the reason for this is
Speaker 1: that you know, the Earth has a magnetic field, and
Speaker 1: that magnetic field converges at the north and south poles,
Speaker 1: the magnetic north and South poles and UH, and sometimes
Speaker 1: that magnetic field gets disrupted, for example, when there's a
Speaker 1: solar flare, and sometimes the solar flare will send enough
Speaker 1: energy to Earth that it it kind of uh will
Speaker 1: twist the magnetic field will realign earth magnetic field that
Speaker 1: tends to dump a lot of energy into the ionosphere,
Speaker 1: and the particles in the ionosphere they'll this is what happens.
Speaker 1: The electrons get elevated to a higher energy state when
Speaker 1: the atoms calm down, essentially they emit photons and we
Speaker 1: we can see that invisible light. And that's when you know,
Speaker 1: if you're at far off to the north and you
Speaker 1: look off and you see these bright flashing lights in
Speaker 1: the sky and they're all these pretty colors, that's what's happening.
Speaker 1: It's actually the same phenomenon that we use to to
Speaker 1: create a laser UM. So in more to laser history UM,
Speaker 1: it was Columbia University's Charles H. Towns who decided to
Speaker 1: try working on atoms at microwave frequencies UM and he
Speaker 1: actually demonstrated in nineteen fifty three that it could be done.
Speaker 1: Except he called his a mazer for microwave amplification by
Speaker 1: the stimulated emission of radiation UM, and he actually got
Speaker 1: the nineteen sixty four Nobel Price or physics UM. Also
Speaker 1: UH Alexander Prokarov and Nikolai Bessov of the PM Lebedev
Speaker 1: Physical Institute in Moscow, who also we're working on the
Speaker 1: problem independently, none of it when it seems weird that
Speaker 1: all these things happen simultaneously, Like we we talked about
Speaker 1: the development of television. How two different people are credited
Speaker 1: with the invention of television depending on whom you ask.
Speaker 1: Shout out to Philo. Yeah, it's just it's just funny
Speaker 1: that that UM, and this happens all the time in
Speaker 1: the development of calculus. But yeah, we weird. Way to
Speaker 1: go Newton, like, can we have a clear winner please? Anyway,
Speaker 1: I'm sorry, but yes, I was gonna say so, yes,
Speaker 1: you you were mentioning the maser that that also is
Speaker 1: something we should point out that laser itself is an
Speaker 1: acronym light amplification by stimulated emission of radiation. You can
Speaker 1: see why laser was picked over that. Yea, And uh,
Speaker 1: do you have who made the first true laser um?
Speaker 1: I do have the first the person who made the
Speaker 1: first true laser um. Well, if you're talking about Gordon Gould,
Speaker 1: that is Oh, that wasn't who I have, But go ahead.
Speaker 1: He is the person who actually got he called it
Speaker 1: the laser um. He's the person who filed for the patent. Now,
Speaker 1: if you're talking about Towns again, he was working with
Speaker 1: Arthur L. Shallow, who was his brother in law UM,
Speaker 1: and they were looking at the infrared light and visible
Speaker 1: light wavelengths. And in December they published a and an
Speaker 1: issue of Physical Review was published and their paper was
Speaker 1: in it. UM. But Gordon Gould actually had his patents
Speaker 1: granted in the nineteen seventies and he's the one who
Speaker 1: made most of the money off of it. Because masers
Speaker 1: had actually been used in atomic clocks and microwave amplifiers,
Speaker 1: but they really weren't using them for much else. And
Speaker 1: lasers which use a different wavelengths of light um there,
Speaker 1: you can use them in different applications, and that's why
Speaker 1: this was so profitable. Are those the people that you
Speaker 1: had in Actually, the one I have specifically was a
Speaker 1: fellow who in nineteen sixty built a laser out of
Speaker 1: a synthetic ruby. Ah, you're talking about THEO yeah, Teddy
Speaker 1: Theodore Mayman. Yes, and uh, that would be the fellow
Speaker 1: who created the first true laser using a synthetic ruby.
Speaker 1: Now right now that that's the kind of laser that
Speaker 1: I think of as being the modern the kind of
Speaker 1: laser were used today. Although he when I think it's
Speaker 1: kind of interesting, he used a photographer's flash, Yeah, as
Speaker 1: a source of stimulation for chromium atoms in a in
Speaker 1: a ruby crystal, synthetic ruby crystal. So when you when
Speaker 1: you're talking about creating a laser, the first step is
Speaker 1: you have to have some sort of medium that you
Speaker 1: are going to, uh, you're going to apply energy to
Speaker 1: in order to excite the atoms within that medium. And
Speaker 1: I understand that's called a game medium and also sometimes
Speaker 1: called a lazing medium. So yeah, and you the the
Speaker 1: process of pouring energy into this is called actually it's
Speaker 1: called pumping. You pump the lazing medium to generate photons.
Speaker 1: That's that. That's a verbie often associate with super soakers,
Speaker 1: I associated with nikes, these old air nikes. Um. But
Speaker 1: the uh yeah, so you what you do is you
Speaker 1: have to generate enough energy within this lazing medium so
Speaker 1: that you're starting to push the electrons into the higher
Speaker 1: orbits or the higher energy states, I should say. And
Speaker 1: what's interest thing is that if the once they the
Speaker 1: electrons start coming back down and photons are admitted. If
Speaker 1: you've if you've arranged the material the right way, the
Speaker 1: medium the right way, and you have it uh contained properly,
Speaker 1: those photons when they strike other atoms will excite the
Speaker 1: atoms they hit, which will then generate their own photons. So, UM,
Speaker 1: it's not self sustaining. It's not gonna stay that way forever.
Speaker 1: You're gonna lose energy eventually through various means. But that
Speaker 1: that helps you. That's why it's called stimulated emission of radiation.
Speaker 1: It's it's you stimulate the emission and then the process
Speaker 1: starts to help sustain itself. UM. Now, with a laser
Speaker 1: you typically happen to have mirrors on either side of
Speaker 1: the lasing medium. So um when the photons start to
Speaker 1: travel through the medium, And by the way, another interesting
Speaker 1: thing here is that when a photon hits another atom
Speaker 1: um and excites the electron, and then the electro and
Speaker 1: comes back down to its ground state and it emits
Speaker 1: another photon, that second photon is going to travel in
Speaker 1: the same direction as the first photon, the one that
Speaker 1: hit it the first time. So if you think about it,
Speaker 1: think of like a series of um of billiard balls
Speaker 1: rights right physics, and just imagine that you somehow manage
Speaker 1: to line up those billiard ball balls absolutely perfectly and
Speaker 1: and they hit exactly the right way, so that when
Speaker 1: the first billiard ball connects with a second, the second
Speaker 1: one continues to travel on the straight line from the
Speaker 1: first one hits the third, third one continues hit going
Speaker 1: a straight line, hits the fourth, and it just becomes
Speaker 1: this chain reaction. Now, because there's a mirror on either end,
Speaker 1: there's actually a complete mirror on one end and a
Speaker 1: partial mirror on the other. Um, the photons when they
Speaker 1: hit the end are reflected back into the medium, and
Speaker 1: then it continues to create these this flow of photons.
Speaker 1: Now that partial mirror on the other side allows some
Speaker 1: photons to pass through, right, and they're all traveling in
Speaker 1: that one specific direction. It's a very intense, uh, coherent
Speaker 1: part of a beam of light. Now, this is the
Speaker 1: light traveling in a straight direction that Nathan was Yes, Yes,
Speaker 1: this is it's coherence is the concept we're talking about here.
Speaker 1: It's it's organized, right, So every photon is moving in
Speaker 1: the same direction as opposed to a flashlight, which is diffuse. Right.
Speaker 1: That and for one thing that the flashlight, when the
Speaker 1: photons are emitted, they're emitted in a more random pattern.
Speaker 1: They're not directed like in a laser. And you may
Speaker 1: even also have a lens that will focus that beam further,
Speaker 1: depending upon what application you have in mind for this laser.
Speaker 1: Like a laser pointer doesn't need to to focus the
Speaker 1: laser in a really intense beam because you're using it
Speaker 1: just to point stuff out and you don't want to
Speaker 1: burn a hole through the wall. Right. Yeah, that's that's
Speaker 1: the type of laser that I own. I have a
Speaker 1: red laser at home that I used to h to
Speaker 1: drive my cats crazy, yes, um, which they very very
Speaker 1: much enjoy and it also doubles nicely as a laser
Speaker 1: pointer if you happen to need one. But that's um,
Speaker 1: you know, they're they're fairly inexpensive because they don't need
Speaker 1: a lot of um high end parts if you will. Um, yeah,
Speaker 1: it's and it really depends two on the type of laser.
Speaker 1: I mean, they're there are a lot of things that
Speaker 1: you can change, um about lasers to change a number
Speaker 1: of things like um, the size of the beam and
Speaker 1: the color, because it has a lot to do with
Speaker 1: the medium. Yeah, we should actually point that out. In fact,
Speaker 1: I'm glad you mentioned that because I forgot to say that.
Speaker 1: The other interesting thing about a laser is that they
Speaker 1: are monochromatic. They are all of a single color. Now
Speaker 1: that color may not even be within the spectrum of
Speaker 1: what we can view. It might be not not not
Speaker 1: with invisible light, because you can have ultra violet lasers,
Speaker 1: you can have infrared lasers. But the color is dependent
Speaker 1: mainly upon the the state, the energy state of the electrons,
Speaker 1: and a lot of that will depend upon what specific
Speaker 1: medium you are using as your lasing medium. Because the
Speaker 1: you know, different atoms have different number of electrons, so
Speaker 1: therefore the the state. The various energy states are going
Speaker 1: to be different depending upon which elements you're using. So um, Yeah.
Speaker 1: For example, a carbon dioxide laser is often used in
Speaker 1: cutting applications, and it's um, it's it's a it's got
Speaker 1: a very large wavelength. The wavelength that we were talking
Speaker 1: about earlier, of course, that's talking about how long the
Speaker 1: a particular peak and trough of Yeah, that would be
Speaker 1: a wave. Uh you know that that determines a lot
Speaker 1: of different properties of lasers. Red lasers tend to have
Speaker 1: a wavelength of around six and ninety four nanometers or gnometers,
Speaker 1: depending on how you prefer it. Um. And remember a
Speaker 1: nanometer is one billionth of a meter. It's tiny, tiny, tiny,
Speaker 1: still big compared to the atomic scale. In the atomic
Speaker 1: scale is about a tenth the size of the nanoscale. So,
Speaker 1: like we said, depending on the medium, that's what's going
Speaker 1: to determine kind of the wavelength and therefore the color
Speaker 1: of the laser. So if you're using something like argon
Speaker 1: fluoride for your laser is going to be in the
Speaker 1: ultraviolet range, which means the wavelength is around ter So
Speaker 1: that's a tiny, tiny wavelength. The carbon dioxide one is
Speaker 1: ten six hundred nanometers, so that's quite a long wavelength.
Speaker 1: And then the stuff that we can see like the
Speaker 1: typical red laser that might be a helium neon laser,
Speaker 1: that that's one that can produce a red color and
Speaker 1: that's around six and thirty three amnometers in wavelength. So uh,
Speaker 1: that's to me, that's a really interesting idea is the
Speaker 1: fact that you know, just by experimenting with different mediums
Speaker 1: or media I should say not mediums, Um, we've determined
Speaker 1: that you can create different colors of lasers and and
Speaker 1: depending and the lasers themselves have different properties that are
Speaker 1: valuable in various applications. Yep. Um. And it it's worth
Speaker 1: noting to um that you mean you could use gases,
Speaker 1: solids or liquids as a medium for for lasers, and
Speaker 1: most of the ones we use our gas, um liquids
Speaker 1: are are the least common from what I understand from
Speaker 1: my research. But UM, yeah, it's uh, it's funny because
Speaker 1: it really the color laser too. You might go on
Speaker 1: to uh shopping sites where they have geek toys and
Speaker 1: uh and look at them and go, well, you know,
Speaker 1: the laser laser pointers like five dollars for a red one,
Speaker 1: but it's ninety or a hundred fifty dollars for blue
Speaker 1: or violet or you know what, what is the deal
Speaker 1: with that? Well? Um, I think part of that is
Speaker 1: that some are easier to make than others. Um. Part
Speaker 1: of that is probably the medium to scarcity of the
Speaker 1: medium and part of its demand. Um. And I think
Speaker 1: part of it also is how cool they look and
Speaker 1: how new they are, because um, now the red lasers
Speaker 1: red laser pointers have been available for so long. Um,
Speaker 1: you know, they're pretty common. I mean you could get
Speaker 1: I I picked mine up as a matter of fact,
Speaker 1: in the grocery store in the pet section. Um. But yeah,
Speaker 1: if you want to, if you want to violate laser,
Speaker 1: they're harder to find. Um. Yeah, I haven't been out
Speaker 1: as long, and they're kind of expensive. Hear, Mace Window
Speaker 1: had to drop three Corelian Freighters in order to get
Speaker 1: his lightsaber. You know, I almost mentioned lightsabers and whether
Speaker 1: or not we were growing our own crystals or not
Speaker 1: for this, and then I thought, I'll wait and see
Speaker 1: if Jonathan mentions it. You can just listen to our
Speaker 1: lightsaber podcast if you want to. That was that was
Speaker 1: a fun one. But yeah, but yeah, it had these
Speaker 1: these are these wavelengths, these lasers and different wavelengths are
Speaker 1: great for different kinds of applications. True, because I know
Speaker 1: you you were, you know, talking about Blu ray players
Speaker 1: Blu ray versus DVD. Yeah, yeah, okay, so DVD players. Um,
Speaker 1: the old DVD players used or still us really red
Speaker 1: lasers to read information off of a DVD. And the
Speaker 1: way this basically works is think of the DVD. It's
Speaker 1: got a it's got a layer on the DVD that
Speaker 1: has information that's recorded and essentially little pits. These little
Speaker 1: pits are read as ones and zeros. What happens is
Speaker 1: a laser will hit the pit or the blank space,
Speaker 1: because that's also information. It's just saying it's a zero
Speaker 1: rather than one. Essentially, I'm oversimplifying. Yes, yes, it's it's complicated.
Speaker 1: But and there's a reflective surface that's beneath that layer.
Speaker 1: So the laser hits the pit or the smooth space
Speaker 1: hits the reflective surface, bounces back towards a cent sore.
Speaker 1: Sincere I'm talking about lack lasers and sin sores, I
Speaker 1: don't know what the heck's happened in me this morning, guys, anyway,
Speaker 1: So the laser hits the pit, hits the reflective service,
Speaker 1: bounces back hits the sensor. The sensor detects whether you
Speaker 1: know what kind of element was on the DVD. That
Speaker 1: gets translated into digital information, which then eventually becomes the
Speaker 1: picture on your television screen. So with a red laser,
Speaker 1: you remember, the red lasers wavelength is around six and
Speaker 1: thirty three ninometers, So there's a certain amount of information
Speaker 1: you could fit on a DVD single layer DVD UH
Speaker 1: that you cannot exceed because the red lasers only able
Speaker 1: to detect something of a size that its wavelength can
Speaker 1: hit and bounce back from. Like if the pits were smaller,
Speaker 1: the wavelength wouldn't even detect it because the wavelength would
Speaker 1: be larger than the the actual element it was trying
Speaker 1: to detect. Well, Blu ray players use a blue laser,
Speaker 1: and blue lasers have a a smaller wavelength, shorter wavelength,
Speaker 1: their wavelength around footers, So essentially you can cram more
Speaker 1: information onto a blu ray disc because the wavelength is smaller,
Speaker 1: and UH, you the path the pattern on the DVD
Speaker 1: if you will, well, I mean, the disc itself is
Speaker 1: doesn't have to be as large for the laser to
Speaker 1: read it, so you can pack more information on there
Speaker 1: because the blue lazer has no trouble reading it at
Speaker 1: a smaller size. Exactly. Yeah, if you if you want
Speaker 1: to think of it in h here's another weird way.
Speaker 1: Think of it like a wall that's covered in in
Speaker 1: in white and black dots. Alright, but the white and
Speaker 1: black dots are maybe like a six inches in diameter.
Speaker 1: So you're using a flashlight, and the flashlight is shooting
Speaker 1: is has a has a circle of about six inches
Speaker 1: in diameter from the distance that you're at the wall,
Speaker 1: and you you you count the number of dots as
Speaker 1: you swipe the flashlight left and right across the wall. Well,
Speaker 1: then let's say that you've got another wall that has
Speaker 1: dots that are two inches in diameter, and you've got
Speaker 1: a flashlight and you've got a light that's two inches
Speaker 1: in diameter. It's you're going to be able to count
Speaker 1: way more dots on that wall than you could with
Speaker 1: the ones that were six inches in diameter. That's the
Speaker 1: same concept here. So it's interesting to me that just
Speaker 1: by switching to a different kind of laser, we've been
Speaker 1: able to cram more information in a storage medium. It's
Speaker 1: a really neat idea. And we talked recently about light Peak,
Speaker 1: which is now called Thunderbolt, at least as far as
Speaker 1: Apple products because it's apparently got an exclusivity deal with Apple. Um.
Speaker 1: But you we talked about light Peak a couple of
Speaker 1: episodes ago, and light Peak uses um infrared Uh uh yeah,
Speaker 1: infrared lasers instead of visible spectrum lasers. But it's same
Speaker 1: sort of concept here is that it's using that to
Speaker 1: shoot information sation from a chip to a device or
Speaker 1: vice versa. Uh. The digital information gets translated into a
Speaker 1: series of flashes of this laser, which get picked up
Speaker 1: by another sensor and then transmitted back into digital information. Now, um,
Speaker 1: there's something else I wanted to talk about that's related
Speaker 1: but not exactly on topic, but it's it's very recent
Speaker 1: and it's really cool, so I thought I would mention it.
Speaker 1: It's okay with you? Please do have you heard about this? Uh?
Speaker 1: This article that was published in the February issue of Science.
Speaker 1: Is it about an anti laser? It is. I knew
Speaker 1: about uncle laser, but I don't know anti laser very well.
Speaker 1: Please all right, let in the interesting full full disclosure.
Speaker 1: I have not read this article. I don't know anything
Speaker 1: about it, but are one of our science editors, Alice
Speaker 1: and louder Milk. She mentioned it to me this morning
Speaker 1: and I thought, oh, I need to look that up,
Speaker 1: and I just didn't have the time to do it.
Speaker 1: So please tell me what is this? Well, I got
Speaker 1: my information not from that particular article, but from the
Speaker 1: Yale Daily News, an article by Antonio Woodford. Uh. And
Speaker 1: and it's relevant to Yale because it's Yale physicists who
Speaker 1: came up with this idea. It's it actually is a
Speaker 1: device that absorbs light instead of emitting light. So that's
Speaker 1: why people are calling at the anti laser. That isn't
Speaker 1: it really what it is? A laser, you know, stimulates
Speaker 1: atoms to to generate light UM and this absorbs light,
Speaker 1: so they're calling it an anti lazer. But it's really
Speaker 1: called and And the reason you'll you'll understand in the
Speaker 1: second why people are calling at the anti laser because
Speaker 1: it's a lot more fun to say than coherent perfect absorber. Yeah,
Speaker 1: I know it's a scientific name. So anyway, um, Uh,
Speaker 1: physicists Douglas Stone and we cow um, we're working on
Speaker 1: a device that absorbs light and basically instead of using
Speaker 1: a game medium, UH, it uses an absorbing medium instead.
Speaker 1: So it's basically a chamber like a laser UM and
Speaker 1: if you shoot two light beams into the two and
Speaker 1: two ends both ends of the device, it will absorb
Speaker 1: around four of infrared light. UM. And basically what happened
Speaker 1: UH is Stone was trying to describe how lasers work
Speaker 1: much as we are trying to do to someone else
Speaker 1: and realize, you know what, I bet you could reverse
Speaker 1: this process and have an absorb light. So as an experiment,
Speaker 1: he decided to work on this and UM, basically you know,
Speaker 1: it was successful in in creating a device that if
Speaker 1: you um, you know, shown a uh an infrared light
Speaker 1: into it, it would absorb the light. And you say, okay,
Speaker 1: well that's a need experiment. But what can you do
Speaker 1: with it? We remember when we were talking just a
Speaker 1: moment ago about transmitting information via light peak or you
Speaker 1: know the blue ray and DVD players. You're transmitting information
Speaker 1: over the laser. UM. You can use uh the coherent
Speaker 1: perfect absorber I'm sorry, anti laser. Yeah, it's not really
Speaker 1: what it's called, but it's so much more fun. Yes,
Speaker 1: it is. UM. You can use it to detect pollutants
Speaker 1: in the air. And because it can basically by by
Speaker 1: shining the light through the pollutants and having it in
Speaker 1: uh end up in the coherent perfect absorber. Um. You know,
Speaker 1: you you can pick up information from that. Also, you
Speaker 1: can use it for wireless communications, transmitting information basically from
Speaker 1: one point to the other with a light on one
Speaker 1: end and the absorber on the other end. Um. So
Speaker 1: they said. Also it could be used in optical computer chips.
Speaker 1: So that will give you another article to write, and
Speaker 1: maybe this time they won't change the name at the
Speaker 1: last minute. I have another possible use for it. Okay,
Speaker 1: you could use it to coat your car and then
Speaker 1: the cops can't tell how fast you're going using a
Speaker 1: laser speed detector. I'm betting that that's not gonna work.
Speaker 1: It's like a stealth car. It's brilliant. I'll make a billion.
Speaker 1: No one steal that. But yeah, they can use it
Speaker 1: in they think they can use in an optical computer
Speaker 1: chips by change to to change light into electricity. Um.
Speaker 1: So it's you know, it's not just an experiment. It's
Speaker 1: something they think they can uh you know, put into
Speaker 1: products in the future and Uh, it's kind of a
Speaker 1: neat idea. I would never have thought to do that. Um.
Speaker 1: But then again, in n I might not have seen
Speaker 1: use for a laser either. So I thought we might
Speaker 1: also talk a little bit about potential hazards with lasers,
Speaker 1: because here's the thing is that when you have this
Speaker 1: intense beam of light, that's a lot of energy concentrated
Speaker 1: into a relatively small space. Yes, and that energy can
Speaker 1: sometimes be dangerous, yes, especially if it's particularly concentrated. So
Speaker 1: there are different levels of laser classifications that UM that
Speaker 1: will essentially will tell you like how dangerous they can be. Uh.
Speaker 1: For example, a class one laser, Uh, they they aren't
Speaker 1: really that hazardous at all, But it goes from class
Speaker 1: one to class four. There's a couple of little sub
Speaker 1: levels in there too, like there's a class you know,
Speaker 1: there's like a class three M and that kind of thing.
Speaker 1: But up to the class four laser, you're talking about
Speaker 1: high powered lasers, which are dangerous to look at and
Speaker 1: are also they can you know, create, they could they
Speaker 1: could burn things they can, including you or other objects. Um.
Speaker 1: And interestingly, a lot of this has to do with
Speaker 1: the wavelength again, So lasers that have a wavelength between
Speaker 1: around eighty to three and fifty nenometers can if you
Speaker 1: were to get hit in the eyes with them, they
Speaker 1: can actually create an inflammation of the cornea UM. And
Speaker 1: then slightly higher than that, up to four nmeters you're
Speaker 1: talking about possibly creating cataracts UM. And then higher than
Speaker 1: that you're talking about retinal burn. Uh. And then uh
Speaker 1: you're talking about corneal burn if you get a little
Speaker 1: higher than that. I mean, it's dangerous stuff, especially around
Speaker 1: the eyes. And that's part of the reason why you
Speaker 1: may have heard stories about UM Pilots and airlines concerned
Speaker 1: with the possibility of people shining lasers into the cockpits
Speaker 1: of airplanes, and uh, then this is the thing. I mean,
Speaker 1: there have been thousands of incidents reported of pilots uh
Speaker 1: noticing that someone's trying to uh direct a laser into
Speaker 1: the cockpit. It's not to burn the person necessarily, but
Speaker 1: perhaps blind them or caused some other uh problem during
Speaker 1: takeoff or landing, and those, of course are the most
Speaker 1: critical times of an when an airplane is is traveling.
Speaker 1: So uh, yeah, lasers are are I mean, they're kind
Speaker 1: of cool to play with, but yes, when you hear
Speaker 1: the warning don't shine this into your eye. Take that
Speaker 1: to heart. Yeah, and don't shine it in anyone else's eye, right, Yeah,
Speaker 1: don't shine it in any eyes. No eyes get get
Speaker 1: shown in. Yeah. I have the feeling that lot of
Speaker 1: people who are are trying to shine lasers into airplanes
Speaker 1: are are just pooling around, um and aren't necessarily trying
Speaker 1: to hurt anyone. But yeah, that's that's not a fun
Speaker 1: prank to pull on someone. I should also say I
Speaker 1: said three M, and that's not right. There is a
Speaker 1: class three three R and three B. Oh, there's it's
Speaker 1: an R and a B R. Yeah, because our article
Speaker 1: is a little outdated, there's been a reclassification of the
Speaker 1: laser system. So actually I need to go in and
Speaker 1: update our article. I just noticed as I was looking,
Speaker 1: I was like, wait a minute, I know that there
Speaker 1: was a reclassification of the laser system. Uh. Yeah, there's
Speaker 1: a class to M, but there's no three M. There's
Speaker 1: three R and three B. But at any rate, Yeah,
Speaker 1: the higher you go in general, the more dangerous the
Speaker 1: laser is to your health and safety. Um. Now, we're
Speaker 1: probably gonna find lots of other cool uses for lasers.
Speaker 1: We've used lasers to do everything from uh, studying things
Speaker 1: at the atomic level to studying things at the cosmic level.
Speaker 1: So it's an incredibly useful tool. And it's really amazing
Speaker 1: that Einstein was able to come up with essentially what
Speaker 1: was the basis of what what all lasers work on?
Speaker 1: Way back in in nineteen six And you know, there
Speaker 1: was no way at the time, no real practical way
Speaker 1: at the time to build anything that would prove that
Speaker 1: his theory was correct. So it took several decades before
Speaker 1: we were able to build something that actually said, hey,
Speaker 1: you know what, he seems to know something about this. Well,
Speaker 1: you know, he he was kind of ahead of his
Speaker 1: time in a lot of ways. Well it's all relative.
Speaker 1: H So that wraps up this discussion. If you do
Speaker 1: want to learn more about lasers, we have several articles
Speaker 1: on the site that relate to lasers and including how
Speaker 1: lasers work, but also our articles on everything from CD
Speaker 1: players which also use lasers, to DVD, Blu Ray, UM
Speaker 1: and tons of other content. And it is a really
Speaker 1: fascinating technology and I recommend looking into it if you've
Speaker 1: ever been curious. UM. Also, there's the the amazing documentary
Speaker 1: film real genius. There's a bunch of students making a laser. Okay,
Speaker 1: that that's that's not a documentary. It's actually a comedy
Speaker 1: from the Eight starring fel Kilmer. But yeah, I I
Speaker 1: recommend all those things because that movie is hilarious. And
Speaker 1: with that, we're gonna wrap up this discussion. If you
Speaker 1: would like to tell us about how you plan to
Speaker 1: use a laser to dominate the Earth or any other
Speaker 1: sort of suggestions of topics that we can tackle, you
Speaker 1: can let us know on Twitter or Facebook. Are handled
Speaker 1: there is tech Stuff hs W, or you can email us.
Speaker 1: That address is tech stuff at tell stuff works dot
Speaker 1: com and Chris and I will talk to you again
Speaker 1: really soon. Pu pu laser for Mora on this and
Speaker 1: thousands of other topics. Is it how stuff works dot com.
Speaker 1: So learn more about the podcast, click on the podcast
Speaker 1: icon in the upper right corner of our homepage. The
Speaker 1: House Stuff Works iPhone app has arrived. Download it today
Speaker 1: on iTunes. Brought to you by the reinvented two thousand
Speaker 1: twelve camera. It's ready, are you