Transcript

How Lasers Work | STUFF YOU SHOULD KNOW

From Stuff You Should Know · Episode page · Watch on YouTube

· 47 min · 8,756 words · 205 timestamped sections

This is the full, timestamped transcript of "How Lasers Work | STUFF YOU SHOULD KNOW", an episode of Stuff You Should Know published February 14, 2026 (47 min, about 8,756 words). It mentions 37 people, works and ideas, including Lasers, Stimulated Emission, Josh Malcolm Clark, Charles W. Chuck Bryant, Albert Einstein.

What this episode is about

The episode explains how lasers work, covering the basic principle of light amplification by stimulated emission of radiation and how photons are produced and directed to create a coherent beam. It also touches on common misconceptions and the broad range of laser applications.

Key takeaways

  • Lasers aren’t magical; they’re highly organized light behavior, proving order beats chaos in physics and punchlines.
  • Visible spectrum trivia: yellow isn’t a single wavelength, it’s a band—surprising nuance for a 'yellow light' stereotype.
  • Supermarkets use lasers daily; scanning your code is a practical reminder that cutting-edge tech hides in mundane routines.
  • Acronym brilliance: LASER nails its own expansion; without 'a' of 'and' it still sounds cooler than most.
  • Color theory detours aside, lasers are matter of frequency; different wavelengths = different energy, same physics, irresistible curiosity.

Who speaks in this episode?

  • Josh (Guest) · 21 min speaking
  • Chuck (Host) · 19 min speaking
  • Jerry (Guest) · 2 min speaking

What is discussed, and when

  1. – 5:00: Lasers, Josh Malcolm Clark, Stimulated Emission, Charles W. Chuck Bryant
  2. – 10:00: Albert Einstein, Lasers, Stimulated Emission, Dark Side of the Moon
  3. – 15:00: Albert Einstein, Stimulated Emission, Lasers, Quantum Mechanics
  4. – 20:00: Microwave Radiation, Richard Spencer, Lasers, Stimulated Emission
  5. – 25:00: Lasers, Solid State Lasers, tattoo removal, Gas Lasers
  6. – 30:00: Lasers, Laser Pointers, Liquid Lasers, Solid State Lasers
  7. – 35:00: Lasers, Pulse Lasers, Charles W. Chuck Bryant, Stuff You Should Know
  8. – 40:00: Lasers, Nuclear Fusion, endoscope, The Pit
  9. – 45:00: Lasers, Laser Cooling, Stimulated Emission, Quantum Mechanics
  10. – 46:54: Josh Malcolm Clark, Stuff You Should Know, iHeart Radio, Royalty

Notable quotes from "How Lasers Work | STUFF YOU SHOULD KNOW"

  • It's about time we did an episode on lasers.
    about Lasers · at
  • Thing as a microwave it's the same thing as a radio wave is the same thing as a gamma ray. It's just the different frequencies make them different kinds of energy. What we call…
    about light · at
  • 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…
    about Stimulated Emission · at
  • Monochromatic, which as we said before, those are the things you need for a laser. So Einstein figured out back in 1917 how to make a laser. And it was you guys figure it out. I'm going to think about some other stuff.
    about Albert Einstein · at
  • Sure. And then the two ends of that crystal were painted reflective silver.
    about Theodore Maiman · at
  • 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 glass or something like…
    about Solid State Lasers · at
  • So, Chuck, there's some there's some lasers that are just super powerful that are being built right now. Of course, physicists are Let's see how powerful we can make something. There's.
    about Charles W. Chuck Bryant · at
  • Stuff You Should Know is a production of iHeart Radio. For more podcasts, iMheart Radio, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.
    about Stuff You Should Know · at

Who and what is mentioned in this episode?

People

  • Josh Malcolm Clark — Person · Host · 3 mentions · first at
    Introduces the show, co-explains laser fundamentals, and guides the discussion through history, types, and applications.
    Welcome to Stuff You Should Know, a production of iHeart Radio and welcome to the podcast. I'm Josh and there's Chuck and Jerry's here, too. And she was making too many laser…
  • Charles W. Chuck Bryant — Person · Co-host · 2 mentions · first at
    Co-leads the explanation of laser properties (monochromatic, coherent, collimated) and discusses applications like medical uses and laser cooling.
  • Albert Einstein — Person · Referenced expert · 10 mentions · first at
    Credited with the theoretical groundwork for photons and stimulated emission, which the hosts describe as essential to making lasers.
  • Theodore Maiman — Person · Referenced inventor/scientist · 1 mention · first at
    Credited with building the first functional laser in 1960 using a ruby crystal gain medium and reflective ends.
  • Charles Townes — Person · Referenced inventor/scientist · 1 mention · first at
    Discussed as a 1950s Bell Labs physicist who built the maser (microwave analog), described as 'halfway to laser town.'
    Did, though, that followed in his footsteps. And in the 1950s, there was a physicist named Charles Towns. He worked at Bell Labs and who he was doing research on microwaves…
  • Richard Spencer — Person · Referenced inventor (anecdote) · 2 mentions · first at
    Mentioned via the famous melted-chocolate-bar anecdote associated with microwave technology, used as a humorous aside during maser discussion.
    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 his shirt. We talked about this, I think, and melted it. Yeah.
  • Chris Hayes — Person · Cultural reference · 1 mention · first at
    Referenced jokingly while describing the 'Dark Side of the Moon' prism imagery as a humorous aside.
    Yeah. With Isaac Hayes's head floating above it.
  • Joey Sara — Person · Anecdotal acquaintance · 1 mention · first at
    Mentioned in a side story about record pressing quality while discussing 'Dark Side of the Moon.'
    A guy who does that for a living. I was hanging out with him in New York with our friend Joey Sara and these two guys who did that and he said, Yeah, some pressing like it's…
  • Noah Wyle — Person · Referenced actor · 1 mention · first at
    Mentioned in discussion of the TV show 'The Pit' and its exposition style in a teaching-hospital setting.
    Last night, I kind of forgot the reason why I was saying there's so much of like of Noah Wy overexlaining everything to all the younger doctors and residents is because it's a teaching hospital.

Companies & orgs

  • Lawrence Livermore Lab — Organization · Research lab (fusion milestone) · 1 mention · first at
    Cited as the site of a 2022 laser-driven fusion experiment achieving net energy gain using 192 lasers.
    Out. Well, you need like plasma concentrations. These are plasma lasers and apparently in 2022 at the Lawrence Liverour lab they used 192 of these lasers to essentially create…
  • iHeart Radio — Company · Producer/distributor · 2 mentions · first at
    Named as the production company for the podcast and referenced for where to find more podcasts.
    Welcome to Stuff You Should Know, a production of iHeart Radio 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 and.
  • Bell Labs — Organization · Historical research institution · 1 mention · first at
    Identified as Charles Townes's workplace during his maser research, connecting institutional R&D to laser development history.
    Did, though, that followed in his footsteps. And in the 1950s, there was a physicist named Charles Towns. He worked at Bell Labs and who he was doing research on microwaves…
  • University of Michigan — Organization · Host institution (laser facility) · 1 mention · first at
    Named as the site of the ZEUS ultra-short pulse laser system discussed as an example of cutting-edge high-power lasers.
    Are being built right now. Of course, physicists are Let's see how powerful we can make something. There's one at the University of Michigan called Zeus Zetto equivalent…

Products & tech

  • Solid State Lasers — Technology · Major laser category · 4 mentions · first at
    Presented as a main laser type using solid crystals/glass (often rare-earth doped) and tied to medical uses like tattoo removal.
  • Pulse Lasers — Technology · Key laser mode · 2 mentions · first at
    Explained as a method to achieve far higher peak power by releasing energy in extremely short bursts rather than continuous beams.
    These even more powerful if we cut that off very quickly 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.
  • Gas Lasers — Technology · Major laser category · 2 mentions · first at
    Presented as lasers using gaseous gain media (e.g., CO2, argon) often excited by electrical current; linked to cutting/welding and medical UV excimer uses.
    All right. Well, can we move on to gas lasers?
  • Laser Pointers — Product · Everyday example / safety topic · 3 mentions · first at
    Used to illustrate low-power diode lasers and to warn about misuse (e.g., shining at airline pilots).
    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.
  • Liquid Lasers — Technology · Major laser category · 2 mentions · first at
    Discussed as dye lasers using organic dyes as gain media, notable for tunability across wavelength ranges.
    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's I just made.
  • Zeus Zetto — Technology · Example of ultra-powerful laser system · 1 mention · first at
    Discussed as an ultra-short pulse laser system at the University of Michigan capable of extremely brief, high-power bursts.
    Powerful we can make something. There's one at the University of Michigan called Zeus Zetto equivalent ultrashort pulse laser system. And then there's one in the UK that's being built called the Vulcan laser.
  • Vulcan Laser — Technology · Example of ultra-powerful laser system · 1 mention · first at
    Mentioned as a UK-built high-power laser, used to convey the scale of modern laser power for extreme-physics research.
    Laser system. And then there's one in the UK that's being built called the Vulcan laser.
  • endoscope — Product · Medical device example · 2 mentions · first at
    Mentioned as a device that can carry lasers into hard-to-reach areas for procedures like shrinking tumors.
    Yep. For sure. all right. So, back to medicals. Since we're talking about the pit, if you ever had an endoscope, that's, when they put a long flexible tube, down your throat a…
  • UPC Code Scanner — Product · Everyday example · 1 mention · first at
    Cited as a common place people encounter lasers (supermarket checkout), reinforcing that lasers are ubiquitous.
    But, like a UPC code scanner at a supermarket checkout, they still have supermarkets right?

Concepts & topics

  • Lasers — Concept · Core topic · 33 mentions · first at
    The episode explains what lasers are, how stimulated emission enables them, and surveys major laser types and applications from barcodes to fusion research.
  • Stimulated Emission — Concept · Core mechanism · 6 mentions · first at
    Explained as the key physical process that produces identical photons without 'spending' the original photon, enabling coherent laser beams.
  • light — Concept · Foundational concept · 1 mention · first at
    Used to contrast ordinary (multi-wavelength, incoherent) light with laser light and to frame lasers as electromagnetic radiation.
  • Nuclear Fusion — Concept · Major application area · 3 mentions · first at
    Discussed as a transformative energy technology enabled by extremely powerful laser systems, including a 2022 net-gain milestone.
    Out. Well, you need like plasma concentrations. These are plasma lasers and apparently in 2022 at the Lawrence Liverour lab they used 192 of these lasers to essentially create…
  • Laser Cooling — Concept · Advanced application · 3 mentions · first at
    Explained as using lasers to slow/trap atoms (particle traps), enabling precision measurement and improved atomic clocks.
    For sure. There's also, this one's pretty sweet, too. It's laser cooling.
  • Fiber Optic Communication — Concept · Everyday application · 2 mentions · first at
    Described as lasers sending encoded information through fiber optic cables for internet/telecom, highlighting efficiency and reach.
    So, these are obviously have long been used in telecommunications and stuff like that. Mhm.
  • Quantum Mechanics — Concept · Underlying theory · 2 mentions · first at
    Invoked via photons, Planck's constant, and Heisenberg's uncertainty principle as the theoretical basis for laser behavior.
    Is. It's the smallest possible measurement of energy that any anything can have on like the quantum level.
  • tattoo removal — Concept · Medical/cosmetic application · 4 mentions · first at
    Used as a concrete example of solid-state laser use and the need for different wavelengths/gain media for different ink colors.
    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…
  • Microwave Radiation — Concept · Analog/precursor concept · 3 mentions · first at
    Used to explain the maser as a microwave analog to lasers and to situate lasers within the electromagnetic spectrum.
    He just basically tinkered around and made his own version of a laser, but rather than using light, he used microwave beams, right?
  • Black hole — Concept · Research target (analogy) · 1 mention · first at
    Used to illustrate what ultra-powerful lasers can help simulate or study (extreme conditions like inside a black hole).
    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?
  • Star — Concept · Research target (analogy) · 1 mention · first at
    Mentioned as an extreme environment that high-power lasers can recreate to study physics under stellar interior-like conditions.
    The Death Star, even though that's a good case use. it's it's so Yeah, it's so they can recreate like the energy in the inside of a star and find out the mysteries of the universe basically.
  • Royalty — Concept · Listener-mail concept · 1 mention · first at
    Appears in listener mail explaining purple's association with royalty (and Jesus Christ) in some funeral traditions.
    It's reserved for family members. regarding the use of purple specifically, this color is typically associated with royalty in Jesus Christ.

Media & podcasts

  • Stuff You Should Know — Podcast · Podcast / episode container · 3 mentions · first at
    The show in which Josh Clark and Charles Bryant present an overview of lasers and related physics and applications.
  • The Pit — Media · Pop-culture reference · 2 mentions · first at
    Referenced as a show featuring a laser brain-tumor procedure, used to illustrate real-world medical laser precision.
    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.
  • Dark Side of the Moon — Media · Cultural reference · 1 mention · first at
    Used as a visual metaphor for prisms/spectrum while explaining light dispersion; also discussed as a vinyl pressing anecdote.
    I'm describing the Dark Side of the Moon album cover.

Full transcript with timestamps

Welcome to Stuff You Should Know, a production of iHeart Radio and welcome to the podcast. I'm Josh and there's Chuck and Jerry's here, too. And uh she was making too many laser noises so we asked her to please go on mute and 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 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. Uh, you know, it's about time we did an episode on lasers.

Mhm. Uh, 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 2 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 need 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. Um, maybe we will do X someday. Let's find out. Okay.

And everybody knows what a laser is, right? Yeah. I mean, I 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.

Mhm. Uh, 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 buy and the of because that's a world class acronym.

Yeah, that would be Lab Seior. If they included those, laser is so much cooler.

Lab Seior doesn't Yeah. It doesn't have that same ring to it as laser. Throw me the lab seor gun.

Someone would say, "No." Yeah. So, um, 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.

Um, but, uh, like a UPC code scanner at a supermarket checkout, they still have supermarkets right?

Uh, 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, like that. That's actually a laser being triggered. You're 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 I was kind of dreading this, but it's Dave did a great job with this article sort of like in the traditional sense like he said.

Yep. Uh, 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. Uh but just like you know elementary school science when you get that prism and your little mind is blown, it still 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 realized 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 um you know, departing in what a laser ends up being.

Yeah. Because so for example the the yellow band what we see is yellow in the visible spectrum occupies the 570 nanometer to 590 nanometer range show off

below that I think you've got what red orange something like that roy g biv I can't remember uh 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 is 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 diff different shades of yellow in there across that the spectrum within the spectrum, I guess.

Yeah. Spectrum within the spectrum. Mhm. Also a great album title. That is a great album title. Or maybe you could have like a a prism

with a beam of light coming in and then the rainbow coming out the other side. Yeah. This 1960s for sure.

Yeah. A pyramid even as a prism. Yeah. With uh Isaac Hayes's 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. 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 presser, a guy who does that for a living. Uh I was hanging out with him in New York with our friend Joey Sara and these two guys who did that and he said, "Yeah, some pressing like it's done by a human, so you might have some records that just sound really awesome cuz 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 a 180 g. Apparently, they said it's 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. Uh you what you just described very well, by the way, was regular light uh 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 mono 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 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 it's not it's made up entirely of yellow light on that 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. Uh the second big uh 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 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 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 sync like that. Like they're 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 cumated, meaning they're all traveling in the exact same direction.

Yeah. I mean, that's that's important. I mean, cumated is sort of a fancy way of saying directional, but uh 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. Uh and it all goes back to that acronym stimulated emission. Uh 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 um 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, "Light's a 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 little things. You can call them pixels, right?

And um 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 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. Uh this is the plon 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 uh plunk. Okay.

I've heard both, but most of the people I've ever heard say plank. I I mean I run in pretty lowbrow crowd.

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

I like the way that you said it the first time. The plunk Einstein. No one says Einstein though. Uh yeah, the plunk Einstein relation um which is uh the energy of each 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 any anything can have on like the quantum level. Yeah. 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."

And they were fig That's pretty good. they were figuring out or he was figuring out I think other people were at the same time that um 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 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 nanconds typically. Yeah. And then it says okay I want to get back to my resting state its ground state and it goes back to its previous orbital. But when it does it poops out a photon.

You know what's funny? What is earlier when I was going over there to my head I said poops out a photon.

Sure. I mean you and I we share a brain when it comes to toilet humor. Yeah that's true. Uh 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

uh 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

and this happens all the time all over the place in in nature uh it 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 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. So, another way of looking at it is the photon essentially goes into the um 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 a like you could make a basket with your shirt and fill it with photons if you do it right.

Yeah. I mean, he he realized that photons like to hang out with one another. So, it it doesn't take a lot to get them uh 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, uh, 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, um, yeah. So, that's stimulated emission. And the 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.

So, it's going to be traveling in the same direction and it's not it's not going to interfere with the first one. So they're cohesive and they're cumated 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 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 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.

All right, we'll be right back with more lasers. All right. So when we left, uh, Einstein did some some great work, um, kind of laying the groundwork, the theoretical foundation of a laser,

and then he was like, "Guys, I like to to think of things with my brain and say them out loud and write them on chalkboards,

right?" Uh, if you want to build this thing, fine. Maybe slide me some cash, but uh, but I don't do that kind of work. So people did, though, uh, that followed in his footsteps. And in the 1950s, there was a physicist named Charles Towns. He worked at Bell Labs and who he was doing research on uh microwaves, microwave radiation, and he was trying to he didn't know it yet, but he was he was halfway to laser town 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 just he used ammonia atoms. He put them in a sealed chamber um and he got them to essentially emit microwave radiation that he was able to um 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 uh to test it, he um aimed it at the uh front pocket of a passing colleague, Percy Spencer, who happened to have a chocolate bar in the front pocket of his shirt. 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 on 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 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 was just Yeah,

it just brought Percy Spencer to mind. Yeah, I like it. Uh so he literally called this

amazer a microwave amplified stimulated emission of radiation. uh he teamed up with a guy, it was a colleague named Arthur uh 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,

exactly. Come on, just get there. I think it was Theodore Mman, um I like to call him my man,

who actually came up with the the laser. Uh he built the first functional laser in 1960

and came up with a name. I think he did. Okay. Up to this point um they were uh they were all theoretical and my man was the first one to actually build one and he used a ruby crystal which um at the time I think had already been dismissed. People were like you can't use that to 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 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 uh with a um with a flash. It was a coilshaped 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 crystal were painted reflective silver. So everything is sort of um 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 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 there Here's a laser. Check it out. Um 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, um, that was it. I mean, that was the first laser that and it was I I 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 It's more complicated than a laser by far.

I I hated that one. I did too. That was a long long time ago. I remember we picked it. We started researching it. I was like, "Wow,

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 blowing tube tube smells beer.

Exactly. And just make a bunch of like drunk jokes. Exactly. Uh All right. So, that that was the first laser. Um, like you said, he used that ruby to begin with, but there are all sorts of gain mediums. Uh, there can be liquids, there can be uh gases, and we should probably go over the five main types of laser. Now,

starting with um like if you've ever been for tattoo removal or um 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 glass or something like that. mix it up with a little with a gain medium like um well it's it's they're all rare earth elements like chromium or something like that.

Uh neodymium is that one? Yeah. Uh there's also uterum. Man, I even looked it up. Yurbium. Yurbium.

Yurbium. I bet is right. That's a That's That looks funny. It It is. It's great though. Y t- eru muturbium. I got it. And all of those basically they dope that um 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 their um phosphorescent properties. These things can generate some photons really efficiently and they're going to generate them in exactly the the wavelength that you want.

That's a solid state laser. 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.

Um, 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. That's a great way to say it. That guy's nice. Uh, 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 uh, according to whatever application they want to use it for. So, it's not just like, hey, these are cool. Uh, let's use let's use this crystal with this uh, doping agent because we just think it sounds awesome. It 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 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 have seen recently when we were on tour. I had a probably 2 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 Chuck's new tattoo.

Well, I'll uh 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 the the gain medium is different right?

There's one called the ND Yag laser. Yeah, that's a really common one. Neodymium doped yrium. Yeah. aluminum garnet. That's the 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, uh can we move on to gas lasers? I think it's time. Yeah. So, obviously they're going to use gas as their gain medium. Uh could be a carbon dioxide laser. Uh could be argon. could be krypton if you're really into comic books. And uh these are different than solid state lers obviously. Uh 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. Um there's all sorts of stuff you can use with gas lasers, but probably one of the the most famous one is using carbon dioxide as the gain medium. And those things can get those photons going. You can weld with it.

That's how that's how powerful these lasers can be. 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 can destroy tissue, but it 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 a a squamoth cell or something.

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

Yeah. Hopefully that you didn't hear about that from a squamama cell being removed,

right? There's also fiber lasers. These are very special lasers. Uh, I don't know how they found this out, but scientists concluded that the um 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 are obviously have long been used in telecommunications and stuff like that. Mhm.

Uh and because they are used in conjunction with an actual cable, uh 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. Um that's another way that lasers are part of your everyday life. Um the if you have fiber internet like you have a laser on one end that your ISP is using to send um 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 uh 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 um 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 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 I think that's wow, too. Yeah. Uh, 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's I just made that up, everybody.

Oh, I fall 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 brainbreaking. 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 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 die lasers, these are sort of brainbreaking, too. They use organic dyes as the gain medium,

which is kind of crazy to think about. But each dye 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 costefficient.

Yeah. I think that's one of the downsides of solid state lasers is 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 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 cat's within us. Well, let's talk about that. We're kind of at that point. Do you play with your cats with laser? Um, pointers.

No, I have, but I they always get lost because they're always small. Oh, gotcha. Gotcha. Um, 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 a electron exchange and hence a flow of electrons and that creates electricity. So that's what these things are powered by. This is the the way that the um 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. 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 is spread out so much that it's just it's like a huge ball of light

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."

Yeah, agreed. Uh well, that's a that's a weak one. and those diode lasers or semiconductor lasers. But um since the very beginning uh science has tried to make the like more powerful lasers

uh and they have done a pretty great job at it and we'll go over some of these but um you measure an uh a laser by how quickly that laser is emitting the energy. So it's jewels of energy emitted per second, right?

They measure that in watts. And uh 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. Pulseed lasers, right? Because like you said, a traditional laser, it's the same amount of energy the whole time the beam is on. With a 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 mindboggling how fast this happens. So fast that your puny brain just sees it as one constant beam of light. Yeah. 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, quintilion of a second how frequently those that thing is pulsing.

Yeah, it's incredible. Uh I think they first demonstrated that in 1961 with that Ruby laser and uh I think they ended up with 100 nancond burst in 1961, which is pretty impressive.

Yeah, for sure. Because a nancond 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 um I think that was what' you say 100 nancond bursts. I saw that with the the tech that they're using now, nancond pulses are called giant pulses.

Yeah. Seriously, that's what they consider them. Yeah. And those are quintilians 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 where that where the beam is released from that. It's 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 quintilionth 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. stuff. You should know. So, Chuck, there's some um 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 Zetto equivalent ultrashort 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 500 million 40 W light bulbs.

Well, 40 watt. Well, yeah, that's true. That's not much. Uh, and the Zeus can generate a pulse of light that's uh 25 quintilion of a second long.

And so, but wait, how much energy does it release? Uh, three pedawatts, baby. Which is 100 times the total electrical output of the entire world in one quick burst. So, these things are they're like um 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 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. Uh, it's it's so Yeah, it's so they can recreate like the energy in 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 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 um it's essentially where you take light nuclei and fuse them together to create a heavy nuclei and a lot of energy is 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 Liverour lab they used 192 of these lasers um to essentially create the world's first nuclear fusion reaction that produced more energy than was put in. There was a net gain.

Yeah. Uh they called that the 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 that's going to change absolutely everything.

Yeah, for sure. Um, so you can use it to for nuclear fusion. You can use really great lasers to um recreate different crazy exotic aspects of the universe. There's also way more pedestrian uses for lasers. like we said, barcodes, fiber optic communication. Um, but there like when you start to look around, lasers are everywhere. Essentially, anything you can bounce light off of or that you can um that will absorb uh light,

you can use a laser for for some application or other. Yeah, for sure. Uh they're all over the medical industry for in all kinds of ways. Uh I think pretty early on they were like, "Hey, these uh using a laser to cut into the human body is way better than a scalpel."

Sure. Um it's way more precise. Uh 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 heal up quicker. So that's they're I mean scalpels are still around, but they you know, lasers are the way to go. I saw that there's a 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. Uh 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. Uh we started watching it. I gave it another try. Yumi 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 Wy overexlaining everything to all the younger doctors and residents is 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. Uh, all right. So, back to medicals. Since we're talking about the pit, if you ever had an endoscope, um, that's, you know, when they put a long flexible tube, uh, 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, Vinnie. Uh, 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? Um, 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 um aesthetic dermatological applications.

Yeah. Cosmetic stuff. Yep. Uh tattoo removal, that kind of thing. Lasic. What about LASIC?

Yeah, Lasic is a big one. um that has become vastly improved as lasers and robots have improved. I think it was first started it first became approved in the US in 1999 and since then it's gotten really good. I think 90% of people who get LASIK uh have between 2020 and 2040 vision afterward

and it's like the pool of people who are um 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,

right, you're going to LASIC's going to benefit you. No, you can have like pretty bad myopia and still benefit from it.

Yeah, in this case, they use the laser to reshape the cornea. Uh, didn't you debate LASIC at one point? Yeah, I'm I'm still thinking about it, but my vision we're 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 uh a little bit lately. I'm not sure why.

I looked into it and I was convinced like this is this is pretty safe and effective and and 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 the that contact lens.

It because it's been wintertime and dry and it makes them like it makes it easier for it to like fold over or something like that. Pop out.

Sucks. I'm sorry. Uh there's also weapons. Of course, you can use lasers for weapons. Uh 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 down troops, but to say blow up a a drone or something like that.

Yeah, they're called uh directed energy systems. Uh some of them attach to like a a turret on a ship.

Um those seem to work pretty well for like you said, like taking down a drone or something like that.

Um they have others. I think the army has one uh a 50 kowatt 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 um locked down and they're like, "Hey, we're driving this thing around." It's not very accurate.

Right. And it's the Striker armored fighting vehicle. Striker with a Y. Yeah. It's like they looked to G.I. Joe stuff to 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 you can um track soil moisture from space to see how bad a drought is. You can uh 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. Uh what they're doing is basically kind of freezing an atom or molecule in place. Uh it's also called a particle trap.

And it's it's the same sort of physics of stimulated emission but kind of in reverse.

Yeah. when a when a 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 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 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 um you can do something like 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 um 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. Um, 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, but I think that was a good good oldfashioned overview of lasers.

A great man. Uh, and since Chuck said old-fashioned, he just accidentally triggered listener mail.

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

Oh, yeah. Purple, actually. Yeah, purple. And, uh, we heard from a listener. Hey guys, I'm writing to share some insight regarding the morning colors at the nearby church. Uh, 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. Uh, in some cases, all in attendance are encouraged to do so, while in others, it's reserved for family members. Uh, 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 uh it may signify recognition of the deceased returning to God

uh 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. Craigily Teresa, what a lovely email.

That was a great email, Teresa. Thank you very much for it. And now your mystery solved, Chuck. That's right. We love emails that solve mysteries that we uh 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 stuffodcast@ iheartradio.com. Stuff You Should Know is a production of iHeart Radio. For more podcasts, iMheart Radio, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.

Questions about this episode

Who speaks in "How Lasers Work | STUFF YOU SHOULD KNOW"?

Josh (Guest), Chuck (Host), Jerry (Guest).

What is "How Lasers Work | STUFF YOU SHOULD KNOW" about?

The episode explains how lasers work, covering the basic principle of light amplification by stimulated emission of radiation and how photons are produced and directed to create a coherent beam. It also touches on common misconceptions and the broad range of laser applications.

What is mentioned in this Stuff You Should Know episode?

37 people, works and ideas are mentioned, including Lasers, Stimulated Emission, Josh Malcolm Clark, Charles W. Chuck Bryant, Albert Einstein, Stuff You Should Know. Each one on this page links to its own page with every episode that mentions it.

How long is "How Lasers Work | STUFF YOU SHOULD KNOW"?

The episode runs 47 min; the transcript is about 8,756 words in 205 timestamped sections.

More from Stuff You Should Know

About this transcript: the episode's spoken words as captioned on YouTube, split into timestamped sections. Reclip.Me locates every person, work and idea in the text, keeps the time it is first named, and quotes the words around it verbatim. Last updated October 29, 2026.