Daniel and Jorge Explain the UniverseWhat makes a laser a laser? Pew Pew Pew!? Zap Zap Zap!?
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Hey, Daniel, let's talk about acronyms.
Acronyms are actually a really really important part of science. Whenever you have a good idea, you have to come up with an acronym or it's not going to be catchy.
Well, I heard there have been some pretty unfortunate acronyms in the history of science.
There are I googled for worst acronyms ever, and I came up with some that you gotta wonder like, people must have known what was going on, you know. So one of my favorites is Phase one Observing Proposal System. So for those of you following along at home, that's pops. So yeah, you can put that together yourself.
But I heard that one day actually grab the y from system, like they consciously made the choice not to be called poops but to be called poops. Well, there is one acronym that's a famous acronym for a physics topic. But I think we think maybe most people don't even know it's an acronym.
Yeah, and maybe that means it's really successful, right, because it's become a word in its own right. You know people actually use the word.
Yeah, and that word is laser pupel.
So do you know what it stands for? Or he don't look it up? Do you know what it stands for?
Test nerd cred test I do it stands for light amplification through stimulated emission radiation.
Being we have a winner, folks, give him a laser.
But I heard that the acrony could have been different. It could have been light oscillation by stimulated emission radiation.
That's right, And I don't think that one would have gone on quite as well. That would be l O s e R. Has some obvious disadvantages.
Yeah, you don't want to be a loser scientist.
That would be I losed too obvious.
Hi'm Horehand and I'm Daniel and Welcome to our podcast Daniel and Hoorhea.
Explain the Universe, in.
Which we talk about all kinds of cool things about the universe.
Yeah, and we take the universe apart, we disassemble its acronyms, and we tell you what it actually means.
Yeah, all the cool things as you see in science fiction movies, books, laser guns, stuff like that.
We break it down and make sense of it for you. So, if you have ideas for what you'd like this to talk about, send them in to feedback at Danielanjorge dot com. We love hearing your topic suggestions.
Today on the program, we're going to be talking about.
Lasers, lasers. How does a laser work?
What is a laser? Who came up with a laser?
Where can I get my laser death ray? These are important questions.
How can I make my living to lazer bout?
You're a cartoonist, you're already lasers, by which I mean you are brilliant and cutting.
That's right, and very focused.
Very focused exactly.
So, Yeah, lasers are. Lasers are awesome. Everyone knows what a laser is. My kids know what lasers are.
Yeah, I mean they're in science fic everywhere. People have laser pens. Right, lasers there. You probably have dozens of lasers in your house, right, lasers used for everything.
Yeah, they're in our everyday lives. Like every time you go buy something at a store, assuming you still go to a physical store, but if they scan your product in, they're using a laser.
That's right. And if you still have a CD player, that thing is read by a laser.
A CD what.
You're too young to understand those things or head for those of you under forty, We used to store music on these shiny little discs.
Yeah, they'd use lasers, so they were they're literally everywhere. I mean, there are optical drives, right, anything that reads a disc. So if you pop in a disc to your PlayStation, that's using a laser in.
There, that's right. And lasers have an enormous variety of applications, you know, from tiny laser pointers to world sized lasers that people are experimenting with to try to deflect asteroids that might blow up the earth.
Yeah, like in the Dead Star and in Star Wars.
Right, that's right, that's a fiction, of course, But the group building a laser to disflect asteroids, that's real m.
They might save the planet.
They might save the planet exactly. So lasers are everywhere. They're definitely an important part of our culture and of our technology and of everything you do. But the question we had was how do they do what they do? What does it mean too laze? How do you build a laser? Could you assemble one from the stuff in your kitchen?
Yeah? Can you shoot it in the movies, like to destroy other speceships?
That's right? Do they really make the pew pew pew sound?
That's the question I want to know the answer to what sound does a laser make? Is it like pu pure.
Or it's definitely one of those?
How good? I hit it on my first three tries. But we were wondering how many people out there know what a laser is and how it works.
I walked around on campus and I asked people, do you know how a laser works?
Those of you listening about it for a second. Here's what people had to say, Absolutely no, sorry, focused light, light gets multiplied and focused.
Okay, cool by light?
Yeah, alright. I guess not a lot of deep knowledge about lasers out there.
I had the impression people think lasers are like you have a light bulb and then maybe you have a lens to focus it, and that's your laser.
I like the person who said, how do lasers work by light? Technically? You're right, you can go wrong with that answer.
That's right. Yeah, go with a very very general answer, how does this work? Physics?
All right?
You could just say physics to any question to answer.
People, really even math? Can I say how does math work?
No, but that's not a topic for our podcast, right because math is outside.
The universe, beyond the scope of this podcast.
That's right. Maybe it's the only thing more fundamental than physics is math.
Maybe. I like how you say, maybe is there is.
There anything else? Maybe philosophy? I guess philosophy and math, you know, down there at the at the down in the dirt and the roots of human intellectual exploration.
Mm.
Yeah, so lasers are pretty interesting, right, They have an interesting history, Like apparently historians don't really know who invented the laser, or they haven't settled on who invented the laser.
That's right. And I heard that one really important science historian actually wrote a poem about it once.
Oh really, is that true?
Yeah? His name is hold On. I have it here let me check my this.
Jorge cham Oh, yeah, that comic laureate of the Internet.
Should we should we read the poem?
Sure, go for it.
I'm not sure if this is supposed to be set to music or rhyme.
Yeah, it's supposed to be said to laser music. So think eighties here and then go for it. So I wrote this when the laser turned fifty about eight years ago. Was the anniversary of the laser.
I'll read it, and you make the pewpuw sounds a right. The laser turns fifty this week, an important event in history. But who developed this amazing technique? That's still kind of a mystery. Was it Ted Maiman who built the first laser? Or was it Towns in Shacklo who wrote the seminole paper? And it goes on like that, several beautifully crafted verses.
Oh thanks, yeah it was You know what happened? I was in Ottawa and I went to visit they have a laser institute at one of the universities there, and they explained to me that the anniversary of the laser was coming up, and so they explained to me how the laser works. And in fact, I think that's kind of related to how you and I started working together, right.
Yeah, you just reminded me of this today. Apparently your comic about the laser is one of the ones that I read and induced to write you an email.
So yeah, the history is kind of funny because the Nobel Prize for the laser, the first prototype for the laser, and the first paper about the laser are all credited to different people, Like, nobody knows who invented this really, Yeah.
It might have been one of these things where like an idea that's whose time has just come? You know, we're on the cusp is sort of the next thing to happen, and a few people contribute bits and pieces here, and some other person puts these things together first there, and it's a bit of a mess. Yeah, it's a bit of a mess. I think it's fascinating also how important it is to assign credit for things like we have the laser. It's awesome. Are people just fighting about the money, like who earns a penny every time they make a laser pointer? Or is it about like the credit and scientific history?
Right?
You know, it's it's interesting to me how how long and nasty this battle is.
You mean, you wouldn't fight to have that in your tombstone. Daniel Whitson invented the laser. Who wouldn't.
Oh, I'm definitely putting that on my tombs, true or not. I mean, you can put anything that you wanted to a troomstone. Nobody fact checks toombstones, do they.
It's like fake news applied to tombstones.
Fake faked tombstones. Oh, I'm taking credit for all sorts of stuff in my tombstone.
Well, let's get into it. What Daniel is a laser?
Right, So a laser is different from a flashlight. Right, It's not just a flashlight with a lens, Okay. A laser is something that produces a bunch of light, usually of the same color. So, like, all a bunch of photons of the same energy, and they should all be going in the same direction, right, So they're perfectly parallel. Meaning if they're like, you know, a tiny distance apart now, then one hundred meters away, or a kilometer away, or a million miles away, they'll still be the same distance.
Apart, perfectly parallel, perfectly parallel photons, right, yeah, exactly, So photons usually of the same color shot perfectly parallel and also with the same way.
Right. Remember, the photons are waves, and they're like all other particles. They're governed by their wave equation, and waves wiggle, right, they go up and they go down, They go up and they go down. And if you have two waves, if they're wiggling in opposite directions, one wiggles up and the other one wiggles down, then they can cancel each other out, right, right, So we want our photons all wiggling the same way. So they all sort of pushed together. It's like folks on a boat rowing at the same time. They all push together for constructive interference to make it stronger.
When they hit something at the end. You want them to be perfectly synchronized. Otherwise they might cancel each other out when they hit something.
Yeah, that's right, or they might you know, cancel each other out part of the way. You know, these things, these interference effects depend on the phase. And so yeah, you want them all pushing in the same direction at the same time. And so that's what a laser produces, right, That's that's what it means to be a laser. And that's an important distinction for people to understand. That's not just like a powerful flashlight or a flashlight somebody's put as in front of. It's really a very different kind of source of light.
It's not just a really bright light. It's like a perfectly ordered, perfectly parallel beams of light.
That's right. And there's two kinds of lasers. One kind is the kind we're talking about where all the photons have the same color, so it's monochromatic. Right, it's a single color of light. All the photons have the same energy, the same color. That's the kind that you make to produce beams. You can also produce laser pulses, right. These are short bursts, and those require having lots of different colors so that you add the add up and cancel out in just the right way to have a localized burst. You can add up all the different wiggles together to make the burst of any shape you want, right.
And that's different than a flashlight, because a flashlight it's just pumping out photons with all kinds of colors and all kinds of phases, and they're all out of sync with each other, all these photons.
That's right. And also they go in in all different directions, right. A flashlight usually has like a tungsten fil lament bulb or something, right, and that's just glowing and it's sending light in every direction. Right, And even if you have it you know, coming out of the front, so it's a little bit shaped. You know. You can take, for example, a flashlight and you can point it at the moon, right, and as you get further away from the source of the light, the size of the beam grows. Right, flashlight, it makes a cone, and that cone grows with distance, So you can point it at the moon and you basically cover the whole moon with your flashlight, right, because by the time you get to the distance of the moon, the cone is huge.
Even if you focus it with like a lens and try to get them parallel, they won't be perfectly.
Parallel exactly right. There's always going to be some spread there. Whereas with a laser. If you take a laser and you point it at the moon, if it's a good laser, when it gets there should have the beam should have the same with as is when it left.
So that's how that's why lasers are powerful, right, because with just a few photons they can go a great distance together, and so they can transmit that information. They're also kind of in sync, so they can deliver all that power when they get there.
That's right. And that example about a laser to the Moon is not just like a made up example. I don't know if you know, but the astronauts who visited the Moon left mirrors on the surface of the Moon so that we can bounce lasers off of them and use that to measure the distance from the Earth to the Moon. I think that's pretty cool.
The Earth's biggest selfie. You can think you can take a selfie by shooting the laser at the Moon.
That's right. Even though this was decades before the concept of selfies, it was it was prescient that way, right. They were forwards forward looking. NASA is always looking into the future.
NASA invented to selfie. We just we just give credit. We just give credit to them.
They can put it on the Actually, the first, the first selfie comes from decades and decades before that. But but yeah, the first astronomical selfie.
For sure, the first laser selfie.
That's right.
Okay, that's what a laser is. It's like it's like something that makes light, that shoots light. That's perfectly in sync and perfectly parallel, and that's really powerful. Okay, So what why is it called a laser? Like, what what does that acronym mean? Light amplified by stimulated emission radiation.
That's right, that's break that down right. The first one is just light. Okay, So photons are light, that's obvious.
Laser.
The last one, the last one is radiation, right, and radiation in this case also just means light. Yeah. I think that's because they didn't want to call it an a laser, right, laser That would have been more awkward with an l.
Or aser or an ace.
So both of those words light and radiation just refer to the photons.
Right, Okay. So it's something that makes light m m.
Something that makes light, and and it makes it in this special way using this process called stimulated emission. Okay. And that's the really the guts of the laser. That's what's going on inside, is that it's a system that creates this stimulated emission. So we should dig into that.
The A and laser means amplified, meaning you're not just making that use sort of amplifying it somehow.
That's right. The basic principle of the laser is. You start with one photon of a color that you want, you know, and you amplify it. Use that to use this system to multiply. You say, I want to start with one photon. Then you create a chain reaction that gives you ten photons, and then one hundred photons, and then a thousand photons, et cetera, et cetera. Grows exponentially until you have a very very intense beam of photons, all the same kind. And the key is the stimulated emission. That's the thing that basically copies the photon says, if you have one of the right wavelength or all the right attributes, then I can make more for you. That's this process called stimulated emission.
Okay, let's get stimulated by stimulated emission. But first let's take a quick break. With big wireless providers, what you see is never what you get. Somewhere between the store and your first month's bill. The price you thoughts you we're paying magically skyrockets. With mint Mobile, you'll never have to worry about gotcha's ever again. When mint Mobile says fifteen dollars a month for a three month plan, they really need it. I've used Mintmobile and the call quality is always so crisp and so clear I can recommend it to you. So say bye bye to your overpriced wireless plans, jaw dropping monthly bills and unexpected overages. You can use your own phone with any Mint Mobile plan and bring your phone number along with your existing contacts. So dit your overpriced wireless with Mint Mobiles deal and get three months a premium wireless service for fifteen bucks a month. To get this new customer offer and your new three month premium wireless plan for just fifteen bucks a month, go to mintmobile dot com slash universe. That's mintmobile dot com slash universe. Cut your wireless bill to fifteen bucks a month. At mintmobile dot com slash universe, forty five dollars upfront payment required equivalent to fifteen dollars per month. New customers on first three month plan only speeds slower about forty gigabytes. On unlimited plan, Additional taxi speeds and restrictions apply. In mobile for details.
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Okay, so laser is something that makes light that's all the same color, the same wavelength, the same direction, the same wiggle, and it's all done by something called stimulated emission. What does that mean?
Right? So the thing that's doing the emission is just an atom. And so you have some medium in your laser. Maybe it's a crystal, maybe it's a gas that doesn't really matter, but it's a bunch of atoms. And atoms can emit light, right, any atom, any atom can emit light. Right, you get things hot and they glow, right, that's something emitting light. So if you pump energy into some material, right, it'll absorb that energy, bring it internally into itself. But then sometimes it gets rid of that energy. That's called emission, and it turns that energy into light. And the way that it does that is it has inside it. It has these electrons. Right, So every atom has electrons whizzing around it, and those electrons have a few certain orbits that they can use around the atom. It's like a bunch of different energy levels. Electrons can't just have any random energy level around it atom. Based on the shape of the atom and the configuration of the protons, etc. There's a few places the electrons are allowed to live, so they're called energy levels, and you can imagine sort of a ladder of these energy levels.
And that's kind of related to the wave nature of electrons, right, because there are waves. They can only fit in so many ways around the atom. Right, it's sort of related to that, right.
It's very closely related. Yeah, the reason that there are discrete energy levels are quantized energy levels is precisely because of those waves and the way the waves fit together around the atom. So a simple way to think about it is when the electron goes around the atom, it's going to do its wiggling, and you want it to build on itself. You don't want it to cancel itself out. So when it comes around one orbit, you need to be in the same place and its wiggle either it's wiggling up or it's wiggling down.
It has to fit a very specific number of wiggles in an orbit. It can just do like three and a half.
That's right. It has to wiggle once or twice or three times. Right, if it wiggles one and a half times, then it's going to get out of sync with itself and eventually cancel itself out. So those are not stable solutions. So you can't have an electron hanging out and wiggling one and a half times around the atom.
So each of those is a different level. It's not like the Earth going around the Sun, like if something moves a little bit, our orbit will increase a little bit. That's not how electrons work. They have very specific orbits that can fit around the nucleus of the atom.
Yeah, that's actually a really interesting deep question. Is the Earth's orbit quantized? Right? Are there infinite number of orbits? That's not the one with a simple answer. If gravity is not quantum mechanical, then you're right, there's an infinite number of orbits the Earth can take. However, if the gravity is quantized, then then you're wrong. And there are energy levels around the Sun. But those energy levels would be so tiny we could probably not even see them anyway.
That might be a subject of a different podcast.
Yeah, exactly. Yeah, so the energy, so the electron has these energy levels it has on these ladder this ladder, it can go up and it can go down.
Yeah, people use the ladder analogy, right, Like electrons can be here or it can go up a level or another level. Right, it's like very discrete steps.
And just like with the ladder, what happens when you go up a level, It takes some energy to do that, right, You have to put some energy into your thigh muscle to push you up, and then you're storing more energy or you have more gravitational energy because you're higher up. The same thing happens with the electron. How does it go up a level? It needs to get energy from somewhere, right, it needs to get heated up or absorb some light or something. So it can go up a level, right, and then it can go down a level. And what happens when it goes down a level, Well, the energy level it was at is fixed and the energy level's going to is fixed, so the energy difference between them is fixed. Meaning every atom has the same levels. And if electrons jump down from one level to the lower one, then they're going to release a photon whose energy is exactly the difference between those two levels, right. Conservation of energy, So the electron loses energy, goes down a level, and it gives off that missing that extra energy in terms of a photon.
Okay, so if the electron goes down a level, it'll shoot out a photon with that energy that it doesn't need anymore.
That's right, exactly. So how do you get a bunch of photons of all the same color in the same direction. When you get a bunch of atoms, you get them all to have their electrons up one level, right, you heat them up, or you pump some energy into them somehow, and then you get them to come down all about the same time.
You get them excited.
You get them excited, right, and then you get them the big let down yay. Oh, And it's when they get the let down that's when they give off a photon, and each one will give off the same color photon. Color the photon is determined exactly by its energy, which is determined by its wavelength. Right. Those things are all connected.
Right, but they don't in a laser, they don't all give them out at the same time. It's kind of like how you said earlier. You want to cause a chain reaction that will make all the atoms in your laser shoot all these photons perfectly insane.
Exactly, So that chain reaction is key, and you can have an atom and you can give it energy. So the electron goes up one level and then it's happened to just hang out there for a while, right, But what happens when another photon of just the right energy level comes by, Like if you're an electron and you're an excited state and there's like a ladders the step ladder step below you, you could go down. If a photon comes by of just that right energy level, it has exactly the energy that's between you and that lower level, then you're more likely to emit. You get pushed sort of out of that energy level. And the reason is that that photon changes the way the environment works. Right. Photons are electromagnetic wave, so it creates a little electromagnetic field there that makes what you were doing a little less stable, so sort of pushes you out of that state down to a lower state and you end up emitting another photon. So the bottom line is, if you're capable of emitting that photon and one photon just like that comes by, then you're going to give it up and emit that photon.
And that's what it's called stimulated emission. Right, Like, if you're an excited atom, you could just spontaneously have your electron drop and admit a photon.
Hmm.
That's called spontaneous emission.
Yeah, But stimulated emission is when you're excited and you get hit by another photon and that causes you to drop a level and admit another photon.
Yeah. It's sort of like peer pressure and they're like, hey, everybody's emitting that red photon. I got one, I could admit one.
And I could admit one.
Yeah, yeah I could, and so I will. This is the right time, you know, And so that's what the stimulated part is, right, it's not this is not nocturnal emissions people. We're talking about photons stimulating electrons into a emitting war photons.
What's the acronym for that? One?
Leaner? So to review, Right, you start, you get some material, you gotta pump it with energy. That's not free energy, right, you got to pump it with energy somehow.
You're gotta get the atoms excited in your media. Yeah, like a lack of stuff.
Yeah, it's like, you know, you're a comedy routine. You need somebody to go out there and warm up the crowd. Right, So first you warm up the crowd, you get it's called population inversion. Maybe you've heard that phrase.
You buy everyone a beer.
That's right. We've discovered alcohol makes people laugh at your jokes more. And so the physics equivalent for lasers, right, is you pump the room with energy and you get all those electrons up at that level, and then one of them will one of them will pop, right, and that will cause the chain reaction. Having one photon around will make all these other atoms which you know are holding that photon inside them basically and burst didn't get rid of it. They'll start emitting, and then more and more will admit.
But they have to get hit by a photon for them to release a photon, right, Like, it doesn't just yeah, it's not because your neighbor shot out a photon that you shoot out a photon. It's like you got you have to get hit by a photon for you to get stimulated.
Yeah, you don't have to absorb it. But having the photon nearby, close enough to interact with the atom will change the electromagnetic vicinity essentially and cause it to do that, and that's why usually you also put this block of atoms in a resonant cavity. Basically you put two mirrors on either side so that you capture the photons and you sort of bounce them around inside. It's the same reason why you have like walls in your oven, right, you want to reflect the energy back so that it builds on itself. Right.
But that whole process I heard is still even a mystery for physicists, Like why exactly does a stimulated atom shootout a photon that's exactly exactly like the one that just went by closely or that hit it. Why does it create a photon that's exactly identical to the one that it saw with the same like wiggle in the same timing, in this exact same direction. That's still kind of a mystery, right.
Well, I think there's some quantum mechanical arguments that suggested. I think there's a lot of the details are not perfectly understood. But you know, the photon creates destabilizes the atom a tiny bit, right, and so we can understand that that's something called Fermi's golden rule, which tells us about how things like to decay, and so Having that photon around definitely helps us understand how the electron would be more likely to jump down, but ye why it comes out in exactly the same phase. For example, I think it's more likely to but not guaranteed, So I think there definitely are some open questions there.
Before we keep going, let's take a short break.
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Okay, So that's the S N L A S E R.
And so that's right.
We covered all the letter. So it's light amplified by stimulated emission radiation.
That's right. And and so you have it in this box and you have these residents, You have a resonant cavity. You have either mirrors right to bounce it back and forth, so the photons you emit make more photons to emit. And you know, you can have a little hole in the side so that some of them leak out, and that's basically your laser. That's how you produce it. But it can be a constant thing. You can be constantly pumping it with energy, pushing the electrons up and then they come down you get photon you push them back up, right, So it can be a continual thing. One of the most interesting lasers I ever saw was actually here on campus at UCI as a professor here Franklin Dollar, who does fusion research, and they're trying to create fusion by focusing a bunch of lasers all in the same place. And he had this amazing setup where it had a bunch of lasers all overlapping in his lab, and he created a ball of plasma that was just floating there in empty space. It was incredible.
Yeah, you can trap atoms with lasers basically, right.
You can do that, But here he was just basically heating the air with a bunch of lasers. By putting a bunch of lasers so they overlapped in one place in space. He heated up the air hot enough to ionize and create a floating ball of plasma. It was like looking at stable lightning. It was pretty incredible.
But these mirrors are pretty cool because they're not just any mirrors that you put it on both sides of your stimulated stuff. It's like one of them has to be a one way mirror.
That's right.
One of them is a regular mirror, but the other one is like a half mirror, meaning that it reflects some of the light but it also lets through some of the light.
Right, that's right. If both of them were perfect mirrors, then you would never get anything out of your laser. You just would all stay inside the cavity. So you have to have one of them be an imperfect mirror so that some of them leak out.
Yeah, So that that's kind of what the laser is. It's kind of like a light echo chamber. Meaning you get you get all your atoms excited, and then you set one one of them off and then that will, for example, go to the right, bounce off the mirror, go to the left, hit another atom, cause it to also emit an exact copy of that photon, hit the other mirror. Then both of them come back to the stuff, and then they stimulate two other atoms, and then that creates four photons and that just kind of builds and multiplies within your echo chamber. But because one of the mirrors is one way or semi transparent, that's where the laser shoots out.
Right, Yeah, yeah, exactly.
Did I just make that up?
You should be the physicist on this podcast, man, But.
I mean that's an important part of it, right, It's like you want to develop an echo chamber. But you have to let some of the light out.
That's right. Yeah, if you don't let some of it out, then it's pretty quickly going to get overheated. Oh, you're gonna laser your own laser.
Right.
And as for all those for all of us who have ever built a death star, you know that you want it to blow up your enemy's basis. You don't want it to destroy your own.
But then stimulating the stuff in between, you can do that several ways. Like your stuff can be a gas or it can be a crystal too, right.
That's right. And if you want a laser to give you light of a certain wavelength, like you want a red laser, a green laser, or an X ray laser or something, you have to find a material that has steps in the ladder. There's steps in their electron ladder that are just the right size. Right. You can't just tune it up to anything you want, right, You can't say I want photons of this frequency. You have to find some material that has electrons that have an energy level that has just the right size. And that's why some of these things are easy, and some of these things are hard, Like X ray lasers are really difficult to build.
And they're really everywhere, right, Like I was thinking, like if you have a mouse in your computer and it's an optical mouse that has a little laser in it, right.
That's right. Yeah, yeah, lasers are everywhere, and it's amazing how influential they have become. You know, And if you look back at the history of the lasers, not only is it a big mess nobody can agree about who invented them, but in the early days there was a lot of skepticism that it was even useful at all.
Right, some scientists thought, who was impossible to make a laser?
Right? Yeah? It was Neil's boor. He tried to make an argument using the Heisenbergen certainty principle. He was like, you can't have that many atoms in a specified state. He thought it would just be impossible. Thought quantum mechanics would make it not possible to make a laser, when in fact, you need quantum mechanics to build a laser. Right, So it works the other direction. So sometimes famous scientists get it wrong.
Was his argument for saying that it was impossible.
Well, you know, the Heisenbergen certainty principle tells you that there's a certain there's a limit to how much information you can have, right, And so he was arguing that having all these atoms in the same state, that you're specifying their energy too tightly. Right, you can't the same way the Heisenbergen certainty principle tells you that you can't know the position and momentum of a particle at the same time. It also applies to the energy and timing information. And so a laser is trying to isolate a bunch of particles to have the same energy all at the same time. And so he thought that that was going to violate the Heisenbergen certainty principle. But clearly it doesn't.
We shut that down with a laser that's right.
With our fully operational battle station.
So there's it's interesting that there are all kinds of different kinds of laser right, Right, Like your mouse can have a laser on it, but you can also use a laser to cut through steel, right, Like, what's the difference between the laser and my mouse and the laser that can cut through things?
Nothing? Your mouse laser can cut through steel. Whoorhea, you just never try it. Now. The difference is just the intensity, right, the number of photons per second. Photons have energy, and when something is hit by a laser, they deposit their energy into whatever is hit by it. If it's not a very bright laser, then you're not I don't have a whole lot of photons per second, then you're not depositing a lot of energy. Right. So that's why you can shine you know, a simple laser pointer and as your skin and it doesn't burn. Right, But if you had ten thousand laser pointers and you hit them all the same place in your skin, be the same as having one really powerful laser, and yeah, you could cut a hole in yourself. So cutting lasers are just lasers with a higher intensity, and they can have more photons per.
Second and they do that. How do you create more intensity? Do you just pump the material more? Or do you do you know what I mean? Like, what's the difference If I had the same material, how do I get more laser out of it?
Yeah, you can pump the material more, you can have more material, you can you must be must also have to do with how you tune the one wayeness of your one way mirror?
Right?
How much energy? And that's that's some fraction of the energy out per second, so there's probably lots of ways to do it.
Well. Lasers are everywhere in our lives. But I heard somebody once told me that the biggest impact lasers have had is in science, helping us make instruments to measure things so that we can expand our knowledge about the universe.
Yeah. Uh, lasers role everywhere. I thought you were gonna say something about like laser lithography, like we can all design our own cutting board logos and have the lasers burn them out.
Yeah. No, the maker movement is very grateful for lasers, but in the sense that you know, like that's how we know for example, or initially that's how we kind of figured out that the gravitational waves measurement that depends on lasers.
Right absolutely. Yeah. That uses two lasers in two different directions, and then you shoot them away and they bounce back and use that as a way to measure the distance. You count the number of wiggles the laser has had. Yeah.
Yeah, and that's how they do a lot of like DNA studies, and you can use lasers to figure out what materials are made out of. So it's kind of in scientific instrumentation has been a huge it's lasers I've had had a huge impact, not just in like consumer products and death rays that were never made, it's in science, right, it's in Lasers have really kind of boosted and amplified what science can do.
That's right. Yeah, we're all emitting more papers thanks to lasers. We're stimulated to emit more papers. Yeah. Lasers also play a big role in fusion research. As we were mentioning earlier. You know, it's a powerful device, right, you have you have light with a specific wavelength, you can focus at a very specific spot, and so it that's what scientists do, you know, they think, how can I answer this question with the tools I have? And that's a very specific tool. It's like a tiny little science scalpel, right, and that lets you sometimes cut problems open that you otherwise couldn't. Yeah.
So the next time you are at the grocery store and are checking out and you hear that beep, that that's a laser at work there. There's a little tiny death ray death rays to scan your your bananas.
That's right, Your fully operational grocery store uses lasers.
Yeah, all right, Well, I hope this discussion stimulated you and made you focus with laser precision.
And if you have any questions, you can emit them to us. We'd love to hear them.
See you next time.
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