How Lasers Work

Welcome to Stuff you should know, a production of IHEARTRADIOW.

And welcome to the podcast. I'm Josh, and there's Chuck and Jerry's here too. And she was making too many laser noises, so we asked her to please go on you because she did, and I assume she's still making laser noises. We just can't hear right now.

You have a little attitude about it.

Too, she did. I mean, I was really mean and kurt, but she didn't have to be that way back.

Yeah, this is a one way street, right, it's.

My way or the highway.

You know, it's about time we did an episode on lasers. This seems like something that we would have tackled in those first formative in that first formative decade, and.

I'm glad we didn't because I think it's good to still do like a traditional you know, how X works episode, we should do one, And how X works it depends on what kind of X you're talking about.

Ruby used to give us an X when she was little, when she was like two years old. If she didn't like something, she would do her fingers as an X.

And she just keeps getting cooler and cooler.

She forgot that she lost that one along the way. I told her to bring that back.

Yeah, that's a good one.

Uncle Josh likes it.

That's like talk to the hand, but way better.

Yeah, exactly.

All right, So we're talking lasers today, not necessarily X. Maybe we will do X someday. Let's find out, okay, And everybody knows what a laser is, right.

Yeah, I mean I feel like it's one of the more like one of those acronyms like scuba that you learn when you're like on the playground. M hm. So in this case, it stands for light amplification by stimulated emission of radiation. And now that I know what a laser is and how it works, they kind of nailed it with that acronym they did.

You you can totally forgive them for the B and the of because that's a world class acronym.

Yeah, that would be lab sere if they included those lasers so much cooler.

Lab se or doesn't. It doesn't have that same ring to it as laser.

Throw me the lab se or gun.

That someone would say. No. So, lasers are everywhere everybody, They're all around you. A lot of them are pointed at you right now, you just can't see them. But like a UPC code scanner at a supermarket checkout. They still have supermarkets, right, Oh yeah, that's right. Everyone goes in and empties all of their bank accounts into them every week to get suesstenates. Well, when you check out, boo boo boop like that, that's actually a laser being triggered.

And it's really not that hard to wrap your head around. Actually I was kind of dreading this. But Dave did a great job with this article, sort of like you here in the traditional sense, like you said, yep, And he does a good job initially by sort of laying the groundwork of regular light compared to a laser light. And I think that's a great way to start.

Well, yeah, if we're going to talk about lasers, we really I mean, we're talking about light. We kind of need to go back a couple of steps and say, okay, there's different kinds of light, you know, like the light we think of as sunlight or a light bulb or something like that, what we would call generally white light is as a lot of people know, all of the colors of the spectrum, the visible light spectrum together coming together to form white light.

That's right, many different wavelengths. But just like you know, elementary school science, when you get that prism and your little mind is blown, it's still kind of blows my mind. You scatter that light into its different wavelengths and it's the colors of the rainbow there. But and this is something that like I don't think I even realize this, even those different wavelengths, it's not a single wavelengths. It's still a spectrum of different wavelengths creating the red or

Yeah, because so for example, the yellow band, what we see is yellow, and the visible spectrum occupies the five hundred and seventy nanimeter to five hundred and ninety nanimeter range. You show up below that, I think you've got what red orange, something like that. ROYGBIV, Yeah, I can't remember above that you've got blue Green, roy g Green, and those just have different wave links. They're all electromagnetic light. It's the same thing as a microwave. It's the same

Yeah, spectrum within the spectrum. Also a great album title.

That is a great album title, Jeszisch. Maybe you could have like a prism with a beam of light coming in and then a rainbow coming out the other side.

Yeah, this is nineteen sixties for sure.

Yeah, pyramid even is a prism.

Yeah. With Isaac Kay's's head floating above it.

I'm describing the Dark Side of the Moon album cover.

I know it's just kidding.

Okay, well you were really throwing me off, you were. That was some meta joking right there.

I have a great pressing of Dark Side of the Moon by the way you do. Yeah, you know, I had a record press or a guy who does that for a living. I was hanging out with him in New York with our friend Joey Ciara and these two guys who did that, and he said, yeah, some pressings like it's done by a human, so you might have some records that just sound really awesome because it was well done. And I was like yeah, and they're you know, one hundred and eighty gram. He was like, that's all bunk,

I do like the heft of a eighty gram.

Apparently, they said, is that's all just for you to make you think it is better because it's heavier.

It's heavier, so it's worth more.

All right. So back to lasers. What you just described very well, by the way, was regular light wavelength within the wavelength. If you talk about the differences of a laser light, you're talking about three main differences, in the first of which is that single wavelength it's monoc like truly monochromatic. That beam of light that a laser is or I guess you know, produces Well, no, it's what it is is is just a very it's a single wavelength, highly highly concentrated.

Yeah, so rather than say a wavelength between five seventy and five for being yellow, this is a five hundred and seventy two nanometer wavelength that is that specific yellow. That's right, and it's it's not it's made up entirely of yellow light on the exact same wavelength. That is incredibly important. That's a huge, huge difference. Lasers don't occur naturally. We've figured out how to make them, and by we, I'm including myself in you.

That's right. The second big difference between laser light and regular light is that it's coherent. So not only is it just a single wavelength, but the photons of the light, and we're going to talk about where they come into play here in a second. Thanks to mister Einstein or doctor Einstein, the photons are perfectly in phase with one another. So if you look at that wavelength, the peaks and the troughs are all perfectly in sync.

Yeah, and not like they're following the same plane and they're just kind of in synct like that like, they're upright above each other, right below each other. They're not interfering with one another in any way whatsoever.

That's right.

And then the last one is that they're colimated, meaning they're all traveling in the exact same direction.

Yeah, I mean that's important. I mean culimated sort of a fancy way of saying directional. But as we'll see, they all have to be traveling that same direction to pick up their little photon buddies.

Yeah. So essentially what you've got is a very specific kind of the exact same kind of light, none of which are interfering with the other photons that are coming out of the laser, all of which are traveling in the same direction, so they do not get in one another's way, and they can be combined very very tightly. And that's essentially what a laser does.

Yeah, for sure. And it all goes back to that acronym stimulated emission, the SE and laser. You can't make a laser without SE, that's true. You can't spell laser without SE, and you can't have a laser without stimulated emission. And our buddy Einstein is the guy who sort of laid the theoretical groundwork. He didn't go out and build a laser. That came later, but he laid the theoretical groundwork for all of this back in the ridiculously in the early nineteen hundreds.

Yeah, so back in nineteen oh five, most people were like, light's a continuous wave, and by proxy, the universe is one smooth, continuous thing. In Einstein's like, I don't think that's true. I think if you zoom in far enough, close enough into the fabric of the universe, you're going to see it's actually made of discrete, little little things and call them pixels, right, And he's like, if that's true,

Yeah, for sure, this is the Planck Einstein, Einstein, what just happened? I was concentrating so heavily. I'm not saying Plank.

I've heard Plank I think that's how most people say.

Oh, I've always heard plank.

Okay, I've heard both, but most of the people I've ever heard say plank. But I mean, I run in pretty low brow crowds.

I think the probably the correctest plank, but most people do say plank. You're right.

I like the way that you said it the first time. The plank Einstein.

No, it says Einstein though. Yeah, the Plank Einstein relation, which is the energy beach photon is equal to its frequency times Plunk's constant e equals HF.

Yeah, and all Plunk's constant is all it is. It's the smallest possible measurement of energy that anything can have on like the quantum level. Right, And so Einstein was like, Hey, I want to figure out how all this stuff kind of interacts because I know that photons interact with electrons. I'm just positive of it.

Wow.

And they were figured that's pretty good. They were figuring out. He was figuring out I think other people were at the same time that when you have sub atomic particles like an electron orbiting an atom, which if you go listen to our periodic Table episode, I think we did a pretty decent explanation of how you know that symbolism

You know what's funny? What as earlier when I was going over there in my head, I said, poops out of photon.

Sure, I mean you and I we share a brain when it comes to toilet humor.

Yeah, that's true. Yeah, that's exactly right. So an atom is going to absorb that energy, and it can do that in a lot of ways, but let's just say in this case, it's like some it gets heated up, you know, like literally heated up. Those electrons are going to jump around and get excited. But once they that makes it unstable. But it wants to be stable. So when it goes back to that state. You're right, it

Yeah, Because here's the thing, right, Like you say you have a photon that hits an atom and knocks an electron into the higher energy state, then that electron poops out a photon. Well, that electron is just absorbed the photon. So another way of looking at it is the photon essentially goes into the electron and comes back out the other side kind of, but there's only one photon ever,

If you do it, right, Yeah, I mean he realized that photons like to hang out with one another, so it doesn't take a lot to get them, you know, traveling in a direction and saying, hey, buddy, come with me, and it creates this sort of sort of like a snowball, like a cascading effect where if you can get them in an excited state and stimulate them and have them pick up other photons and have them all travel in the same direction, you're like halfway toward laser town pretty much.

You can see the outskirts of town and the light shooting up in the sky.

Yeah you can.

So yeah, So that's stimulated emission. And the key here is you don't have to spend a photon to get a photon, right, You can excite the atom in other ways as long as it's already in its excited state. When the photon comes along, it's going to produce another photon. Now, for the purposes of lasers, what's really really important here is it is going to produce an exactly identical photon as the first one that passes by, right, traveling in the same direction, and it's not going to interfere with

Yeah. And if you say, well, wait a minute, I thought you said nineteen oh five, like it even took Ein Einstein a little while to get there, you know, that's right, took a little while. So should we take a break.

Yeah, I feel like a break is imminent.

We'll be right back with more lasers, all right. So when we left, Einstein did some great work kind of laying the groundwork, this theoretical foundation of a laser. And then he was like, guys, I like to think of things with my brain and say them out loud and write them on chalkboards. If you want to build this thing, fine, maybe slide me some cash. But I don't do that kind of work. So people did though, that followed in his footsteps, and in the nineteenth fifties it was a

In this case, what's nuts is this guy figured it out. He just basically tinkered around and made his own version of a laser. But rather than using light, he used microwave beams. Right.

Yeah, he built like a thing.

Yeah, he just he used ammonia adams. He put him in a sealed chamber and he got them to essentially emit microwave radiation that he was able to concentrate into a beam. Right, So that cascading effect happened just like we discussed before, and essentially the only difference is it

I think we talked about this, did we do one of microwaves. Yeah, okay, well that would be exactly where we talked about it then, probably.

Yeah, and they weren't colleagues. I just made that part up. But that was a that was for you, buddy.

Oh no, wait, there was a chocolate thing though, what right?

Yeah, yeah, yeah, that happened. But separately, I think Spencer was in the presence of some microwave generator and his chocolate bar melted. And now that went on to invent microwaves. This thing was totally different. It's just yeah, it just brought Percy Spencer to mind.

Yeah, I like it. So he literally called this a mazer, a microwave amplified stimulated emission of radiation. He teamed up with a guy. It was a colleague named Arthur Shallow, and he said, let me see if we can do the same thing with light, and we'll call it an optical maser. And everyone was like, buddy, it's right there in front of your face, like, come on, just get there.

I think it was theor myman I like to call him my man who actually came up with the laser. He built the first functional laser in nineteen.

Sixty and came up with a name.

I think he did Okay. Up to this point, they were all theoretical and my man was the first one to actually build one, and he used a ruby crystal, which at the time I think had already been dismissed. People were like, you can't use that to make a laser. And he's like, let me try again, and he did some more calculations. He's like, the ruby's actually going to be great. So he used a pink ruby crystal as what's called the gain medium.

Yeah, that's like the material lasing material that you would use exactly.

That's where the atoms that you get excited are all stored.

Yeah, So he surrounded that crystal with a with a flash. It was a coil shaped flash bulb. So that's that's going to be the thing that you know, the heat or whatever or the light that stimulates the initial reactions the pump. Sure, and then the two ends of that

Yeah, all of these photons came out at six hundred and ninety four nanometers, which I guess is the precise wavelength of ruby red.

Yeah, I guess so.

And he showed that like there, there, here's a laser. Check it out. Let me see your face. Basically, I think was how he showed it off right. He would just wave it in people's faces.

That's why he's my man.

So that was it. I mean, that was the first laser that and it was what you want to say, like it was as easy as that. Of course that's not easy, but the principle of it is kind of like you said, it's simple to understand, which is great. Like we did one on the breathalyzer, and it is so ridiculously complicated. It's more complicated than a laser by far.

I hated that one.

I did too.

That was a long period of time ago.

I remember we picked it, we started researching, and I was like.

This sucks.

Wait, why am I not understanding this? It was just so complex. Let's never talk about it again.

I think we just wanted the explanation to be like blow into tube smells beer exactly.

You just make a bunch of like drunk jokes.

Exactly, all right, So that that was the first laser, Like you said, he use that ruby to begin with. But there are all sorts of gain mediums. There can be liquids, there can be gases, and we should probably go over the five main types of laser now, starting with like if you've ever been for tattoo removal or like had a skin cancer with laser removal, they're using a solid state laser in that case, and it's called solid state because they're using a solid crystal or a

Yeah, there's also a bitterum you abitterum man I even looked it up, udbium atbium.

Aterbium I betze, right, that's a that's why that looks funny.

It is great though, why t t E r b I U m yatterbium I got it And all of those Basically they dope that say, like you could still use ruby, but you would create like a ruby crystal that's doped with these impurities that you've selected based on their say like reflective properties, or they're phosphorescent properties. These things can generate some photons really efficiently, and they're going to generate them in exactly the wavelength that you want. Yeah,

You know, Emily knows not much about football, doesn't care, but there's always a few plays that she knows of, and it's always very funny. Patrick Mahomes is one of them, and every time she'd hears of him or anything, she just goes my homes very nice, sort of like my man.

Oh no, I'm with you. That's a great way to say it. Nice.

One thing I wanted to point out though about these different types of blazers is all of them are that they use different types of blazers according to whatever application they want to use it for. So it's not just like, hey, these are cool, let's use let's use this crystal with this doping agent because we just think it sounds awesome. It's all highly specific to what you want to end up using it for.

Yeah, Like even like tattoo removal you said, which I'm in the process of I'm getting towards the end there, buddy.

How's it looking pretty gone?

Pretty light? Yeah? It start? Yeah, I mean you can still see it, especially if you walk up to it, but you could also miss it if you weren't looking for it's getting like that, Just like while that guy's got mildew on his arm.

I took the other tack. As you have seen recently when we were on tour, I had a probably two inch by two inch tattoo that I covered with half of an arm sleeve.

I didn't see it. You haven't shown it to me? Oh?

How was was I always in long sleeves?

Yeah? And I forgot to ask. I actually thought about that when we were researching this. I was like, I haven't seen chucks do tattoo.

Well, i'll I'll take my shirt off in front of you soon.

Okay. But even with the tattoo removal ones. They have different types of solid state lasers. The gain medium is different. Right. There's one called the n d YAG laser. Yeah, that's a really common one. Neodymium doped yetrium. Yeah, aluminum garnet. That's the gain medium. And that's for I don't remember what that one's for I think different color like regular color tattoos, whereas like if it's green, to use a different kind of in gain medium.

Yeah.

Yeah, so it is extremely specific.

All right, well, can we move on to gas lasers.

I think it's time. Yeah.

So obviously they're going to use gases or gain medium. It could be a carbon dioxide laser, it could be argne, could be crypton if you're really into comic books. And these are different than solid state layers. Obviously, in solid state the atoms are excited by a light source. In this case, it's an electrical current, and it's going to get them going.

Yeah, it gets them excited. There's all sorts of stuff you can use with gas lasers, but probably one of the most famous one is using a carbon dioxide as the gain medium, and those things can get those photons going. You can weld with it. That's how powerful these lasers can. You can weld metal with that stuff. And then at the same time, if you use a different gas, you might have a eximer laser. You can actually break the bonds that hold molecules together. You can alter cells, you

Yeah, or if you've ever heard of something being laser cut, then it's probably going to be a gas laser doing that business.

Yeah, hopefully that you didn't hear about that from a squama cell being removed.

Right.

There's also fiber lasers. These are very special lasers. I don't know how they found this out, but scientists concluded that the cloaks usually or the textiles found with bog bodies, have some sort of magical properties that if you use them as a gain medium, they make really great lasers. Hence fiber lasers.

Right, But in this case they're used in conjunction with a fiber optic cable. And so these are obviously have long been used in telecommunications and stuff like that. And because they are used in conjunction with an actual cable, they're very very efficient. Convert more than fifty percent of the electricity that's input into light. But that d YAG laser has about a three percent efficiency rate.

Yeah, that's pretty efficient. That's another way that lasers are part of your everyday life. If you have fiber Internet, like you have a laser on one end that your ISP is using to send communications or encoded information along a fiber optic cable, and your modem is basically a laser receiver that translates it into whatever your router needs to explain it to you.

Yeah, that man, that breaks my brain like vinyl records, does you know?

Yeah? It's pretty cool though, And that's the thing. So it's just like when radio with radio waves, we figured out how to encode information, and radio waves we figured out how to do that with light. It's just lasers are way more efficient. They can travel way longer than radio waves can. And apparently they're starting to look into

Wow.

I thought. I think that's wow too. Yeah, what about liquid lasers or die lasers? I should probably say, because you played that so straight, my explanation of what the gain medium is for fiber lasers that I just made that up.

Everybody, Oh, I fall victim again.

Did you thought that they used the cloaks from bog bodies for that.

Man, I don't all of this stuff is so brain breaking. Nothing nothing. Would You could say human feces and I'd be like, yeah, of.

Course that'd be man, that'd be gross. But I'll bet you could. I think you could use anything with atoms that's excitable to potentially make a laser.

You've become such a good straight person that it's just hard to tell anymore.

It's hard to tell with you too, Hey, thanks, Yeah, thank you. Uh.

Liquid lasers or dye lasers, these are sort of brain breaking to these organic dyes as the gain medium, which is kind of crazy to think about. But each die, like uh, will produce a different laser light because they're going to have, you know, because it's a color, like a different wavelength.

Right.

And these are really cool because you can actually tune them to a very you can manipulate them and tune them within a very specific range for specific uses.

Yeah. So one laser can be used for all sorts of different things, which is I'm sure quite cost efficient.

Yeah.

I think that's one of the downsides of solid state lasers. It's like one thing you can be with one laser.

Yeah, Although That.

Would be cool if like it's just a cartridge you can pop out and put in a new a new crystal. Yeah, that'd be sweet.

They should work on that.

They have to be, you know, like the cost of lasers have come down tremendously. I'm sure we'll eventually get there.

Yeah, just ask my cat, my cats with an us.

Well, let's talk about but that. We're kind of at that point. Do you play with your cats with laser pointers? No?

I have, but they always get lost because they're always small.

Oh gotcha? Gotcha? Well that is actually a kind of laser. That's why they call them laser pointers. They're the weakest laser.

Yeah.

But they use diodes, which are two different materials that when you put them together with a place where they interface, creates an electron exchange and hence a flow of electrons and that creates electricity. So that's what these things are powered by. This is the way that the light. Photons get made from the excited atoms, and they're super cheap.

Oh.

Sure, that's a real problem. Actually, I think it happens a couple thousand times a year in the US alone.

Yeah, concerts too, people do that stuff.

Sure. The reason you're not supposed to do that with airline pilots is because by the time it reaches the cockpit, it has spread out so much that it's so man it's like a huge ball of light. Yeah, that is so bright in the cockpit that they can't even see the instruments anymore.

Yeah.

So it's not like you're just putting like a little dot on somebody's cheek. You are blinding everybody in the cockpit. Right. Then it's a huge problem that you really should not do.

Yeah. And also, what's funny about messing with someone doing a very important, dangerous job where hundreds and hundreds of lives are at stake. Yeah, let's mess with that person.

Yes, and I think everyone's parents should sit them down and say, yeah, let's talk about laser pointers, because you probably aren't grasping what a problem this is.

Agreed. Well, that's a weak one. Those diode lasers are semiconductor lasers. But since the very beginning, science has tried to make the more powerful lasers and they have a pretty great job at it. We'll go over some of these. But you measure in a laser by how quickly that laser is emitting the energy, so it's jewels of energy emitted per second. They measure that in watts, and they figured out pretty early on that a continuous beam of

Yeah, pulse lasers right, because, like you said, a traditional laser, it's the same amount of energy the whole time the beam is on the pulse laser, it's kind of like stopping up the uh, the beam of light, so that it just the energy builds up behind it and then you open it up again and when you release it, it's this ultra concentrated beam of energy, and it's it's mind by uggling. How fast this happens so fast that your puny brain just sees it as one constant beam

Yeah, it's incredible. I think they first demonstrated that in nineteen sixty one with that Ruby laser, and I think they ended up with one hundred nanosecond burst in nineteen sixty one, which is pretty impressive.

Yeah, for sure, because a nanosecond is a billionth of a second.

Yeah, so in nineteen sixty one they were able to get that first laser by pulsing it up to one thousand times more powerful than my man's device.

Yeah. This was a year after he built that first laser, right, Yeah, So I think that was when you say one hundred nanosecond bursts. I saw that. With the tech that they're using now, nanosecond pulses are called giant pulses. Yeah, seriously, that's what they consider them.

Yeah, and those are quintillions of a second, which is hard to even wrap your head around for sure.

Right, So these things, these pulses are just like that's it also, Chuck, I think goes to show you how quickly energy builds up in the chamber that where the beam is released from that it's it's like creating a thousand times or ten thousand times or however many times stronger beam just from backing it up in like one quintillionth of a second. Yeah, sure, you want to take a break.

Yeah, let's take a break, and let's talk about just sort of real world uses and what's going on out there.

Okay, So, Chuck, there's some there's some lasers that are just super powerful that are being built right now. Of course, physicists are like, let's see how powerful we can make something. There's one at the University of Michigan called zeus Zetiwa Equivalent Ultra Short Pulse Laser System. And then there's one in the UK that's being built called the Vulcan Laser.

Yeah, and these, I mean, the one in the UK has a power of five hundred million forty what light bulbs, well forty well, yeah, that's true, that's not much. And the Zeus can generate a pulse of light that's twenty five quintillions of a second long.

And so but wait, how much energy does it release?

Three petawats baby, which is one hundred times the total electrical output of the entire world in one quick burst.

So these things are they're like, they're so powerful and energetic that they're one of the main things they're going to be used for is to study what it's like inside a black hole or a star or something like that. That's that's like what they're able to recreate and see what happens when it bounces off of an apple or something like that. What happens when you bounce a black hole off of an apple?

Yeah, that's that's basically why they're trying to create these this powerful. It's not so they can blow up the Death Star, even though that's a good case use. It's so, yeah, so they can recreate like the energy and the inside of a star and find out the mysteries of the universe basically exactly.

There's another thing you can use really really powerful lasers for, and that's nuclear fusion. And we did a whole episode on nuclear fusion, I think in twenty nineteen that was one of my favorites of all time, and it's this whole thing that's the promise of basically free, unlimited energy that you can power anything with with almost like what you're getting out is way more than what you're putting in.

Yeah, they called that the Right Brothers moment as far as lasers go, sure, because you got a net gain for the first time. They focus those lasers at a capsule the size of a peppercorn, and that did it. And I bet that was a great day in that lab.

I'm sure. I mean, once we get to nuclear fusion, that's that's going to change absolutely everything.

Yeah, for sure.

So you can use it for nuclear fusion. You can use really great lasers to recreate different, crazy exotic aspects of the universe. There's also way more pedestrian uses for lasers, like we said barcodes, fiber optic communication. But they're like when you're start to look around, lasers are everywhere. Essentially, anything you can bounce light off of or that that will absorb light you can use a laser for for some application or other.

Yeah, for sure, they're all over the medical industry for in all kinds of ways. I think pretty early on they were like, hey, these using a laser to cut into the human body is way better than a scalpel. Sure, it's way more precise, there's less damage on the tissue it self kind of self cauterizes as it goes, So it's going to be sterilizing the tissue that surrounds it. It's going to be less blood loss, you're going to

I saw that there's a brain tumor laser procedure that uses a five millimeter hole in the skull and you get discharged the next day. That's how accurate and amazing these things are. Plus also, it's way easier to attach to a robot than to give a robot a scalpel to use.

Yeah, I hate to bring it up again, but that was just on an episode of The Pit, that exact.

Case use that you just mentioned, the laser tumor.

Yeah, the tiny hole in the skull.

We started watching it, I gave it another try, you me and I did, and it's it is pretty good and engrossing.

Yeah, engross it is. Yeah, and I figured out too watching last night, I kind of forgot the reason why I was saying. There's so much of like of Noah Wiley over explaining everything to all the younger doctors and residences because it's a teaching hospital.

Yeah, there you go, which is.

A great vehicle to explain whatever the heck is going on to the viewer at home, you know, yep, for sure. All right, So back to medicals, since we're talking about the PIT. If you ever had an endoscope, that's you know when they put a long flexible tube down your throat a lot of times, or up your nose or who knows what holes they can put them into these days, it.

Depends if it's a rubber hose, you know where that goes.

That's right, Vinny. Essentially you can access these tough to reach areas with these tiny little tubes, and in this case, you can have a laser attached to it and send it in there to shrink a tumor like you were talking about.

Right, And then you can also use them to do things like destroy the epidermis and then heat up the dermis underneath to get rid of like spots or something like that. For all sorts of esthetic dermatological applications.

Yeah, cosmetic stuff.

YEP, tattoo removal, that kind of thing.

Laser, what about lask Yeah, Lasik.

Is a big one that has become vastly improved as lasers and robots have improved. I think it was first started at first became approved in the US and nineteen ninety nine, and since then it's gotten really good. I think ninety percent of people who get Lasik have between twenty twenty and twenty forty vision afterward. And it's like the pool of people who are candidates for it are is pretty wide. It's not like, yeah, if you can if you need just like those magnifying readers that you

Yeah, in this case, they use the laser to reshape the cornea. Didn't you debate laser at one point?

Yeah, I'm still thinking about it. But my vision we're basically at an age where your vision changes fairly rapidly and you want it to stabilize or else you'd get lasik once and then you'd end up needing glasses when your vision degrades again.

I think Emily has been debating it to a little bit lately. I'm not sure why.

I look into it and I was convinced, like this is this is pretty safe and effective, and yeah, yeah I would do it. I'm just not there yet.

I feel like when I've seen you lately, you're having trouble with a contact.

Lens because it's been wintertime and dry. Uh it makes them like it makes it easier for it to like fold over something like that. Popca sucks.

I'm sorry.

There's also weapons. Of course, you can use lasers for weapons. Apparently the Army, the Navy, and the Air Force are developing laser weapons to different different levels of success, but they're definitely working on them, not to necessarily like you know, mow doown troops, but to say, blow up a drone or something like that.

Yeah, they're called directed energy systems. Some of them attached to like a turret on a ship. Those seem to work pretty well for like you said, like taking down a drone or something like that.

Mm hmm.

They have others. I think the army has one fifth to kill a WATT that's on an armored fighting vehicle, but that hasn't done so well because you know, for a laser weapon to be pretty effective, it has to be super tightly focused and pretty locked down. And they're like, hey, we're driving this thing around and it's not very accurate, right.

And that's the Striker armored fighting vehicle, Striker with a Y. Yeah, it's like they look to G. I. Joe stuff to come up with ms for it.

For sure.

There's also this one's pretty sweet too. It's laser cooling. And there's also so many different applications, like you can you can track soil moisture from space to see how bad a route is. You can track how badly ice is receding in the in the polar areas. You can you can do everything with with lasers. They're really great in case that hasn't gotten across so far, but this one, to me is just amazingly cool.

Yeah, no pun intended laser cooling. What they're doing is basically kind of freezing and at them or molecule in place. It's also called a particle trap, and it's the same sort of physics of stimulated emission, but kind of been reverse.

Yeah, when an atom poops out a photon that kind of pushes it in the opposite direction that the photon's traveling. They figured out that they can use lasers to keep to basically balance that out. So these things are still producing photons, they're still doing their thing. They're in energetic states and oscillating and doing all sorts of stuff like they're supposed to, but they're just not moving around in

Yeah, it just slows it down such that it's basically stopped.

Yeah, but it's still doing its thing. It's not moving around while it's doing it right. So, now that you have an atom trapped, you can do something like this is the future of atomic clocks. You can measure the oscillations oscillations of that one specific atom so precisely that atomic clocks are about to be just ridiculously more reliable than the atomic clocks today, which I think we can all agree are pretty reliable. So that's a huge groundbreaking use for that.

Yeah, for sure. I mean it's easier to study something that's sitting still exactly. Yeah.

Yeah, now that I think about it, that basically overcomes Heisenberg's uncertainty principle, where you can't measure something and know where it is at the exact same time. Apparently Heisenberg didn't think of lasers.

That's a nerdiest sentence you've ever said. Oh, come to think of.

It, you got anything else?

I got nothing else that you know, there's obviously a lot more about it. I think that was a good, good old fashioned overview of lasers.

Great man, And since Chuck said old fashioned, he just accidentally triggered listener mail.

I'm going to call this an answer to a question. I love it when we put out a question we get answered. We were talking about color psychology, and I wondered because I have a African American church around the corner from me.

Oh, yes, that purple.

Actually, yeah, purple, And we heard from a listener. Hey, guys, I'm writing to share some insight regarding the morning colors at the nearby church. While traditions can vary between African American churches, I hope the following information is helpful. In the twenty first century African American traditions, it is common for individuals attending a funeral to where the deceased person's favorite color, which is what I thought might be happening.

Oh.

In some cases, all and attendance are encouraged to do so, while in others it's reserved for family members. Regarding the use of purple, specifically, this color is typically associated with royalty in Jesus Christ. If you consistently see purple at the church, it may be it may signify recognition of the deceased returning to God, or maybe just the person's favorite color. So I truly appreciate your program allows me to stay present and provides a welcome escape from the

That was a great email, Chorisa, thank you very much for it, and now your mystery solved.

Chuck, that's right.

We love emails that solved mysteries that we were wondering about. So if you've got a solution to one of our mysteries, we would love to hear it. You can also write in for any other reason. Just send your email to stuff podcast at iHeartRadio dot com.

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