Stuff You Should Know - How Lasers Work

Episode Date: February 12, 2026

It turns out that lasers are even cooler than they look. And as far as acronyms go, they’re pretty solid in that respect too. There’s way too much cool stuff about lasers to tease here so listen to this old school SYSK episode and let lasers blow away.See omnystudio.com/listener for privacy information.

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Welcome to Stuff You Should Know, a production of IHeart Radio. Oh, 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 mute. She did, and I assume she's still making laser noises. We just can't hear her right now. She had a little attitude about it, too. She did. I mean, I was really mean in 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. Mm-hmm. 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 on 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. Man, she just keeps getting cooler and cooler. She forgot that.

She lost that one along the way. I need to tell 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 later. 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. Mm-hmm. 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 can totally forgive them for the buy and the of because that's a world-class acronym. Yeah, that would be Lab Seor. They included those. Lasers so much cooler. Lab Seor doesn't have that same ring to it as laser.

Throw me the Lab Seor gun. 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?

Yeah. Oh, yeah, that's right. Everyone goes in and empties all of their bank accounts into them every week. Right, to get sustenance. Well, when you check out, boop, boop, boop, like that, that's actually a laser being triggered. It's scanning your UPC code. So lasers are everywhere.

They're at the supermarket, at least. That doesn't necessarily mean you understand them. I didn't understand them until we started to research this. Did you? No, and it's really not that, like, 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 he's in the traditional sense, like he 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, kind of blows my mind. You scatter that light into its different wavelengths. It's so beautiful. 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 wavelength. It's still a spectrum of different wavelengths creating the red or the blue or the yellow or whatever. And that's kind of

where we find ourselves, you know, departing in what a laser ends up being. Yeah, because So, for example, the yellow band, what we see is yellow and the visible spectrum occupies the 570 nanometer to 590 nanometer range. You show off. Below that, I think you've got what, red, orange, something like that, Roy G. Biv. Yeah. I can't remember. Above that, you've got blue, green, Roy G, green. And those just have different wavelengths.

They're all electromagnetic light. It's the same thing as a microwave. It's the same thing as a radio wave. And the same thing as a gamma ray. It's just the different frequencies make them different kinds of energy, what we call the visible spectrum. The point is, is within all those different nanometer wavelengths, say from 570 to 590, there's different kinds of yellow. There's different shades of yellow in there across that, the spectrum within the spectrum, I guess. Yeah, spectrum within the spectrum.

Also a great album title. That is a great album title. Jazz Fusion. Maybe you could have like a prism with a beam of light coming in and then the rainbow coming out the other side. Yeah, this is 1960s for sure. Yeah, pyramid even is a prism. Yeah, with Isaac Hayes' head floating above it. I'm describing the Dark Side of the Moon album cover.

I know, I was just kidding. Okay, well, you were really throwing me off. 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. A presser, a guy who does it for a living, I was hanging out with him in New York with our friend Joey Sierra 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, 180 gram. He was like, that's all bunk, by the way. He's like, it just makes you feel better that it's heavier. And I was like, oh, man, that's disappointing. No, I do like the heft of an 880 gram. Apparently, they said it'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, and the first of which is that single wavelength.

It's 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 just a very, it's that single wavelength, highly, highly concentrated. Yeah, so rather than, say, a wavelength between 570 and 590 for being yellow, this is a 572 nanometer wavelength that is that specific yellow.

That's right. And 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 and 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 Mr. Einstein, or Dr. 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 insane. Yeah, and not like they're following the same plane and they're just kind of in sync like that. Like, they're up right 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 colomated, meaning they're all traveling in the exact same direction. Yeah, I mean, that's important. I mean, colomated's 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 S.E. 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 1900s. Yeah. So back in 1905, most people were like lights and continuous wave.

And by proxy, the universe is, one smooth, continuous thing. And Einstein was 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 things. Yeah. You can call them pixels, right?

And he's like, if that's true, then light can't be one continuous wave either. So I think they're actually made up of those little tiny packets that I'm going to call photons. And he turned out to be right. He had a great equation for it, too. It's so elegantly simple. That's the thing about Einstein. He could come up with like three different things and could completely change our understanding of the universe.

Yeah, for sure. This is the Planck, Einstein. Einstein. What just happened? I was concentrating so heavily on not saying Plank. I've heard Plank. I think that's how most people say it. Oh, I've always heard Plunk.

Okay. I've heard both, but most of the people I've ever heard say Plank, but I mean, I run in pretty lowbrow crowds. I think probably the correct. is Planck, but most people do say Plank, you're right. I like the way that you said it the first time, the Planck Einstein. No one says Einstein, though. Yeah, the Plank-Einstein relation, which is the energy of each photon is equal to its

frequency times Plank's constant. E equals HF. Yeah, and all Planck'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. That's pretty good. They were figuring out, or he was figuring out, I think other people were at the same time, that when you have subatomic 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.

that, you know, that symbolism or that visualization of it is not very correct. But for all intents and purposes for this, let's say that these electrons orbit in different orbits around the atom. And when a photon hits it, that orbit, that electron goes up in energy, I think for like a 100 nanoseconds typically. Yeah. And then it says, okay, I want to get back to my resting state. It's ground state, and it goes back to its previous orbital.

But when it does, it poops out a photon. You know what's funny? 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 gets heated up, you know, like literally heat it 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 poops out, That photon, Einstein saw this, called it spontaneous emission. Yeah. And this happens all the time all over the place in nature. These photons are getting pooped out all over the place. But Einstein was like, well, hey, if it happens all the time naturally, he theorized maybe we can stimulate it to do this.

Maybe we can make this happen and control that emission. 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, and then that electron poops out a photon. Well, that electron has just absorbed the photon. Right. 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.

One gets absorbed. One's produced. What Einstein figured out is with stimulated emission, you can use a photon to create another photon, without losing the first photon. And if you do that a bunch of times, buddy, you can have like, like you could make a basket with your shirt and fill it with photons 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 Lasertown. 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. Going in the same direction. Traveling in the same direction, and it's not going to interfere with the first one. So they're cohesive and they're

collimated and they're exactly the same. They're monochromatic, which, as we said before, those are the things you need for a laser. So Einstein figured out back to the in 1917, how to make a laser. And it was like, you guys figure it out. I'm going to think about some other stuff. Yeah. And if you say, well, wait a minute, I thought you said 1905. Like, it even took 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. In 2023, a story gripped the UK, evoking horror and disembant. The nurse who should have been in charge of caring for tiny babies is now the most prolific child killer in modern British history.

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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. Right. 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 1950s, there was a physicist named Charles Towns. He worked at Bell Labs. And he was doing research on microwaves, microwave

radiation. And he was trying to, he didn't know it yet, but he was halfway to Lasertown because he was trying to find ways to concentrate a beam of microwaves 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 used ammonia atoms.

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 wasn't a light, it was a microwave beam. And to test it, he aimed it at the front pocket of a passing colleague, Percy Spencer, who happened to have a chocolate bar in the front pocket of a shirt. Oh, we talked about this, I think. And melted it. Yeah. And Percy Spencer never forgave him because that was his favorite short sleeve button down shirt. 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, right? Yeah, yeah, yeah. That happened, but separately. I think Percy Spencer was in the presence of some microwave generator and his chocolate bar melted. And he went on to invent microwaves. This thing was totally different. It's just, it just brought Percy Spencer to mind. Yeah, I like it. So he literally called this a mazer, a microwave amplified, stimulated, omission of radiation. He teamed up with a guy. It was a colleague named Arthur Shalow. And he said, let me see if we can do the same thing with light. And we'll call it. an optical mazer. And everyone was like, buddy,

it's right there in front of your face. Like, come on. Just get there. I think it was Theodore Maimon. I like to call him my man. Who actually came up with the laser. He built the first functional laser in 1960. 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 lazing 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 flash. It was a coil-shaped flash bulb.

So 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 crystal were painted reflective silver, so everything is sort of kind of trapped in there together, encouraging all those photons to bounce around and get a little wild and create more photons and say, hey, you know,

We're doing something here, guys. And all, yeah, all of these photons came out at 694 nanometers, which I guess is the precise wavelength of Ruby Red. Yeah, I guess so. And he showed that, like, there'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. And it was, 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. Yeah. It's more complicated than a laser by far. I hated that one. I did too. I was a long, a long time ago. I remember we picked it. We started researching, and I was like, this sucks.

Wait, why am I not understanding this? Yeah. It was just so complex. Let's never talk about it again. I think we just wanted the explanation to be like blow in tube, tube smells beer. Exactly. You just make a bunch of like drunk chokes. Exactly.

All right. So that was the first laser. Like you said, he used 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, you've ever been for tattoo removal or like had a skin can't

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 glass or something like that, mix it up with a gain medium. Like, well, they're all rare earth elements, like chromium or something like that. Neodymium, is that one?

Yeah. There's also Ibiterum. Yudiburum. Man, I even looked it up. Yudurbium. Yeterbium. Yeterbium, I bet is right. That looks funny.

It is great, though. Y-T-T-E-R-B-I-U-M. Y-T-R-B-I-U-M. I got it. And all of those, basically, they dope that, say, like, you could still use Ruby. Yeah. 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 their 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. That's a solid state laser. It follows in the tradition of that original my man's laser from 1960. You know, Emily knows not much about football, doesn't care, but there's always a few players that she knows of, and it's always very funny. Patrick Mahomes is one of them.

And every time she hears of him or anything, she just goes, my homes. Very nice. Sort of like, my man. Oh, no, I'm with you. Yeah. That's a great way to say it. Nice. One thing I want to point out, though, about these different types of lasers is all of them are, they use different types of lasers according to whatever application they want to use it for.

So it's not just like, hey, these are cool. 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 toward the end there, buddy. How's it looking pretty gone? Pretty light. Yeah, it's 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. It's getting like that. Just like, wow, that guy's got mildew on his arm. I took the other tack, as you has 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 I always in long sleeves?

Yeah, and I forgot to ask. I actually thought about that when we were really. research in this. I was like, I haven't seen Chuck's new 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 game medium is different, right? There's one called the ND Kohl-Yag laser. Yeah. That's a really common one. Neodymium-doped yitrium. 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, you have to use a different kind of gain medium. 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. Could be a carbon dioxide laser. Could be argon, could be Krypton if you're really into comic books. And these are different Then solid state laders, obviously. In solid state, the atoms are excited by a light source. In this case, it's an electrical current that'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 an exomer laser, you can actually break the bonds that hold molecules together. You can alter cells. You can destroy tissue, but it uses UV light so it doesn't produce heat.

So that's how you can use that on someone's skin without burning them, but still, say, removing like a squamous cell or something. 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 squamacel 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. So these 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. So they convert more than 50% of the electricity that's input into light, but that ND

Yag laser has about a 3% efficiency rate. Yeah, that's pretty efficient. That's another way that lasers are part of your everyday life. If you have fiber internet, 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, 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 in 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 this to transmit information between the Earth and the moon. Oh, boy. So you'll just be able to, you'll have basically not even fiber optic.

internet. You'll have laser internet on the moon. Wow. I think that's wow too. Yeah. What about liquid lasers or dilators? I should probably say because you played that so straight, my explanation of what the gain medium is for fiber lasers, that's, I just made that up, everybody. Oh, I fall a victim again. Did you, 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. 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. Liquid lasers or dye lasers, these are sort of brain-breaking too. They use organic dyes as the gain medium, which is kind of crazy to think about. But each dye 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 do with one laser.

Yeah. Although it would be cool if, like, it's just a cartridge you can pop out and put in 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 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, but they use diodes, which are two different materials that when you put them together with a place where the 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. They're not very powerful. And that means that over a fairly short distance, I think like hundreds of meters, they, Basically, they're not a tiny point any longer. Yeah.

And I was looking into this, because when I hear laser pointers, I think of jerks, like, trying to shine in the light of an airline pilot. Oh, sure. That's a real problem, actually. Yeah. It happens a couple thousand times a year in the U.S. 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 is spread out so much that it's just, 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, 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 or semiconductor lasers. But since the very beginning, science has tried to make the more powerful lasers. And they have done a pretty great job at it. We'll go over some of these. But you measure a laser by how quickly that laser is emitting the energy. So it's joules of energy emitted per second. They measure that in watts.

And they figured out pretty early on that a continuous beam of light emits a constant amount of energy over time. So they were like, hey, I bet we can make these even more powerful if we cut that off very quickly over and over and over and admit pulses of energy because it builds up and it just gets stronger and stronger. And they tried it out and it really worked. Yeah, pulsed 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 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 mind-boggling how fast this happens. So fast that your puny brain just sees it as one constant beam of light. Yeah. We don't have the technology to slow it down enough, I don't think, to see the pulsing because we're talking billions, trillions, quadrillions, quintillions of a second, how frequently the thing is pulsing. Yeah, it's incredible.

I think they first demonstrated that in 1961 with that Ruby Laser. And I think they ended up with 100 nanosecond burst in 1961, which is pretty impressive. Yeah, for sure. Because a nanosecond is a billionth of a second. Yeah. So in 1961, they were able to get that first laser by pulsing. it up to 1,000 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, what did you say, 100 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 all. Also, Chuck, I think, goes to show you how quickly energy builds up in the chamber where the beam is released from, that it's like creating a thousand times or 10,000 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.

Hi, this is Joe Winterstein, host of the Spirit Daughter podcast, where we talk about astrology, natal charts, and how to step into your most vibrant life. And I just sat down with a mini driver. The Irish traveler said when I was 16, you're going to have a terrible time with men. Actor, storyteller, and unapologetic, Aquarian visionary. Aquarius is all about freedom-loving and different perspectives. and I find a lot of people with strong placements in Aquarius are misunderstood. A son and Venus and Aquarius in her seventh house spark her unconventional approach to partnership.

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This MSS officer has no idea the U.S. government is on to him. But the FBI has his chats, texts, emails, even his personal diary. Hear how they got it on the Sixth Bureau podcast. I now have several terabytes of an MSS officer, no doubt, no question, of his life. And that's a unicorn. No one had ever seen anything like that. It was unbelievable. This is a story of the inner workings of the MSS and how one man's ambition and mistakes

opened its vault of secrets. Listen to the Sixth Bureau on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. In 2023, a story gripped the UK, evoking horror and disbelief. The nurse who should have been in charge of caring for tiny babies is now the most prolific child killer in modern British history. Everyone thought they knew how it ended. A verdict? A villain. a nurse named Lucy Letby.

Lucy Letby has been found guilty. But what if we didn't get the whole story? The moment you look at the whole picture, the case collapses. I'm Amanda Knox, and in the new podcast, doubt the case of Lucy Lettby, we follow the evidence and hear from the people that lived in, to ask what really happened when the world decided who Lucy Lettby was. No voicing of any skepticism or doubt. It'll cause so much harm at every single.

single level of the British establishment of this is wrong. Listen to doubt the case of Lucy Lettby on the IHeartRadio app, Apple Podcasts, or wherever you get your podcasts. So Chuck, 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, Zetawa equivalent ultra-short pulse laser system. And then there's one in the UK that's being built called the Lowe.

Vulcan laser. Yeah, and these, I mean, the one in the UK has a power of 500 million 40-watt light bulbs. Well, 40-watt. Well, yeah, that's true. That's not much. And the Zeus can generate a pulse of light that's 25 quintillions of a second long. And so. But wait, how much energy does it release?

Three petawatts, baby, which is 100 times the total electrical. output of the entire world in one quick burst. So these things are like, they're so powerful and energetic that what 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 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 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 2019. 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. And it's essentially where you take light nuclei and fuse them together to create a heavy nuclei and a lot of energies released. It's just we haven't quite figured it out. Well, you need like plasma concentrations. These are plasma lasers. And apparently in 2022 at the Lawrence Livermore Lab, they used 192 of these lasers to essentially create the world's first nuclear fusion reaction that produced more energy than was put in.

There was a net gain. Yeah. They called that the Wright Brothers moment as far as lasers go. Sure. Because you got a net gain for the first time. They focused 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 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 there's, like, when you start to look around, lasers are everywhere.

Essentially anything you can bounce light off of or that you can, that will absorb light, you can use a laser 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-cotterizes 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 heal up quicker. So that's there. I mean, scalples are still around, but lasers are the way to go. I saw that there's a brain tumor laser procedure that uses a 5mm 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 mean I did, and it is pretty good and engrossing. Yeah, and gross. 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? Yeah, 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 aesthetic dermatological applications.

Yeah, cosmetic stuff. Yep. Tattoo removal, that kind of thing. Lasic? What about Lasic? Yeah, Lasic is a big one. That has become vastly improved as lasers and robots have improved. I think it was first started, first became approved in the U.S. in 1999.

And since then, it's gotten really good. I think 90% of people who get LASIC have between 2020 and 2040, 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 buy at the pharmacy, you're going to, LASIC's going to benefit. You know, you can have like pretty bad myopia and still benefit from it. Yeah, in this case, they use the laser to reshape the cornea. Didn't you debate LASIC at one point? Yeah, I'm, 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 would get LASIC once and then you'd end up needing glasses when your vision degrades again.

I think Emily has been debating it too a little bit lately. I'm not sure why. I looked into it and I was convinced like this is pretty safe and effective. 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 that contact lens. Because it's been wintertime and dry. It makes it easier for it to like fold over or something like that. Pop out.

I gotcha. It sucks. 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 levels of success. But they're definitely working on them. Not to necessarily like, you know, mow down 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. They have others. I think the Army has one, a 50 kilowatt 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. 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 GI Joe stuff to come up with names 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 track soil moisture from space to see how bad a drought, is. You can track how badly ice is receding in the polar areas. You can do everything 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 an atom 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 photons 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 space or. while they're doing it. Yeah. So they're essentially, they're just, it's like a tractor beam holding it where you want it. Yeah, it just slows it down such that it's basically stopped. Yeah, but it's still doing its thing. It's just not moving around while it's doing it, right?

So now that you have an atom trapped, you can do something like, like this is the future of atomic clocks. You can measure the 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. You know, there's obviously a lot more,

but I think that was a good old-fashioned overview of lasers. Agreed, 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 answer. We were talking about color psychology, and I wondered because I have a African-American church around the corner for me.

Oh, yeah, the purple. Actually, yeah, purple. And we heard from a listener, hey guys, 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 21st century African-American traditions, it is common for individuals attending a funeral to wear the deceased person's favorite color, which is what I thought might be happening. Oh, neat. In some cases, all in 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 daily news cycle. I look forward to becoming just a tad bit smarter as I continue to be an enthusiastic listener. Corrigley, Teresa. What a lovely email. That was a great email, Teresa. Thank you very much for it. And now your mysteries solve, Chuck. That's right.

We love emails that solve 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.com. should know is a production of IHeartRadio. For more podcasts My Heart Radio, visit the Iheart radio app. Apple Podcasts are wherever you listen to your favorite shows. I'm Amanda Knox, and in the new podcast, Doubt the case of Lucy Letby, we unpack the story of an unimaginable tragedy that gripped the UK in 2023. But what if we didn't get the whole story?

Evidence has been made to fit. The moment you look at the whole picture, the case collapsed. What if the truth was disguised by a story we chose to believe? Oh my God, I think she might be innocent. Listen to Doubt, the case of Lucy Lettby, on the IHeartRadio app, Apple Podcasts, or wherever you get your podcasts. Hi, it's Joe Interesting, host of the Spirit Daughter podcast, where we talk about astrology, natal charts, and how to step into your most vibrant life. And today, I'm talking with my dear friend, Krista Williams. It can change you in the best way possible. Dance with the change.

Dance with the breakdowns. the embodiment of Pisces intuition with Capricorn power moves. So I'm like delusionally proud of my chart. Listen to the Spirit Daughter podcast starting on February 24th on the IHeart Radio app, Apple Podcasts, or wherever you listen to your podcast. This is Special Agent Regal, Special Agent Bradley Hall. In 2018, the FBI took down a ring of spies working for China's Ministry of State Security, one of the most mysterious intelligence agencies in the world.

The Sixth Bureau podcast is a story of the inner workings of the MSS and how one man's ambition and mistakes opened its fault of secrets. Listen to the Sixth Bureau on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. This is an IHeart podcast, guaranteed human.