Speaker 1: Get in touch with technology with tech Stuff from how
Speaker 1: stuff Works dot com. Hey there, and welcome to tech Stuff.
Speaker 1: I'm your host, Jonathan Strickland. I'm an executive producer with
Speaker 1: how Stuff Works in a lot of all things tech,
Speaker 1: and today we're going to revisit a topic I have
Speaker 1: talked about numerous times. I've covered the topic of lasers
Speaker 1: on quite a few episodes of tech Stuff. In fact,
Speaker 1: if you've been listening long enough, you know I used
Speaker 1: to always bust out the laser kind of dr evil
Speaker 1: pronunciation at least once in every episode. So we got
Speaker 1: that all the way good to know we can go
Speaker 1: right into the actual meat of this episode. So I
Speaker 1: thought today we were going to cover some specific lasers
Speaker 1: and explain what people are doing with those lasers. And
Speaker 1: I think most of us are familiar with the general
Speaker 1: concept of lasers, but we're gonna talk a little bit
Speaker 1: about how they work because it's important to understand the
Speaker 1: Bay six in order to get a deeper appreciation for
Speaker 1: the high powered lasers I'm going to talk about today,
Speaker 1: because we're talking about some of the most powerful lasers
Speaker 1: in the world in this episode. So lasers are focused
Speaker 1: beams of light they're used in you know, wicked light
Speaker 1: shows like with Pink Floyd, or they're used to frustrate
Speaker 1: household pets. In science fiction, they're used either by or
Speaker 1: against robots and aliens or both. In the real world,
Speaker 1: they're used for all sorts of stuff, from conducting experiments too,
Speaker 1: in order to learn more about stuff like you know,
Speaker 1: quantum effects, all the way to you know, removing unwanted hair. Now,
Speaker 1: it would not be an episode of tech stuff if
Speaker 1: I didn't take the opportunity to at least go over
Speaker 1: the basics of how a laser works. So tuck in
Speaker 1: here we go. The word laser used to be an acronym,
Speaker 1: so I guess technically it's still kind of is an acronym,
Speaker 1: but we recognize laser as being a noun all on
Speaker 1: its own, so you don't have to capitalize all the
Speaker 1: letters the way you would with a typical acronym. The
Speaker 1: letters do stand for light amplification by stimulated emission of radiation.
Speaker 1: But what the heck does that mean? All right, this
Speaker 1: requires us to go back into some basic elementary school
Speaker 1: science stuff. You remember the structure of an atom, right,
Speaker 1: you that you got the nucleus in the middle. It's
Speaker 1: made up of protons and neutrons. Around that nucleus orbit
Speaker 1: one or more electrons, depending upon which element you're talking about,
Speaker 1: whether or not it's an ion, the electrons and have
Speaker 1: it a space around the nucleus that we call the
Speaker 1: electrons orbital or its energy shell or energy level. So
Speaker 1: electrons can only have certain discrete values of energy. They
Speaker 1: cannot be you know, any value between two. It's one value,
Speaker 1: and then the next layer level up is another value,
Speaker 1: and so on. They are discreet. Each energy shell can
Speaker 1: only hold a certain number of electrons. The shell closest
Speaker 1: to the nucleus is what we would call the K
Speaker 1: shell or the one shell. It can hold two electrons.
Speaker 1: Next out is an orbital that can hold an additional
Speaker 1: six electrons, so now you have up to eight total.
Speaker 1: The third shell can hold an additional ten electrons, so
Speaker 1: you could have a possibility of eighteen electrons with three
Speaker 1: electron shells are orbiting an atom or nucleus, I should
Speaker 1: say not not orbiting an atom, because the atoms the
Speaker 1: whole thing. Anyway, each of those energy shells are important.
Speaker 1: It tells you the ground state for any given electron.
Speaker 1: It will always be at the lowest energy shell it
Speaker 1: can inhabit. So if an energy shells full, so if
Speaker 1: that burst energy shells full, the electron has to be
Speaker 1: in the second shell or or higher, depending on how
Speaker 1: many there are there. Now, if you add energy to
Speaker 1: an atom, that energy would cause those electrons to move
Speaker 1: into higher in G shells, to move further out from
Speaker 1: the nucleus. So if you pump energy into atoms, the
Speaker 1: electrons begin to move further out. And if you pump
Speaker 1: enough energy, and you could actually strip electrons away from atoms,
Speaker 1: at least temporarily, but you would then have a charged
Speaker 1: nucleus and you probably have some free electrons running everywhere.
Speaker 1: They would quote unquote want to get back together because
Speaker 1: those opposite charges would attract one another. But what happens
Speaker 1: if you stop adding energy to the atom, Well, the
Speaker 1: electrons will return to their normal ground energy states. However,
Speaker 1: they cannot do that while still holding on to that
Speaker 1: energy you pumped into them. So first they have to
Speaker 1: release that excess energy in some way, and electrons do
Speaker 1: this by releasing photons, the particles of light. That's one
Speaker 1: part that's really important to remember with lasers. The other
Speaker 1: big important thing to remember is that frequency or wavelength,
Speaker 1: and thus the color of light released is dependent upon
Speaker 1: both the lasing medium itself, what that material is made
Speaker 1: out of, and the energy difference between the excited state
Speaker 1: of the electron and its ground state. How much energy
Speaker 1: did you pour into this thing. Different atoms will release
Speaker 1: different frequencies or colors of light. So, for example, if
Speaker 1: you excite the electrons in a ruby lazing medium that
Speaker 1: has a lot of chromium ions in it, it will
Speaker 1: produce a red light assuming you're doing the normal amount
Speaker 1: of energy pouring into this. Other lasing media will produce
Speaker 1: different wavelengths of light and thus different colors. That can
Speaker 1: include light that's actually outside the visible spectrum, so you
Speaker 1: can have lasers that are infrared lasers or ultraviolet lasers.
Speaker 1: Those would be invisible to the human eye. But as
Speaker 1: I mentioned, the wavelength also also depends upon how much
Speaker 1: energy you pumped into the electrons before they return to
Speaker 1: their ground state. Now, unlike the light we would get
Speaker 1: from an incandescence source like a light bulb, all the
Speaker 1: photons from a lasing medium will be of the exact
Speaker 1: same wavelength, so they'll all be the same color. Moreover,
Speaker 1: the photons are in are are coherent. That means that
Speaker 1: if you were to chart the waves of a laser,
Speaker 1: all the photons would match up with their crests and
Speaker 1: troughs in lockstep with one another. Normal visible light consists
Speaker 1: of photons of different wavelengths and they are not coherent.
Speaker 1: They are not moving at the same lockstep pace. The
Speaker 1: coherence of a laser allows it to remain focused in
Speaker 1: a tight beam over great distances. Directionality is another important
Speaker 1: fact factor with lasers. Now that's in sharp contrast to
Speaker 1: the light from an incandescence source, which is diffuse not coherent.
Speaker 1: For your typical, you know, laboratory laser, the way you
Speaker 1: would stimulate the lasing medium is you would expose the
Speaker 1: lasing medium to an extremely intent flash of white light
Speaker 1: from powerful flash lamps for a fraction of a second. Typically,
Speaker 1: this is called pumping the lasing medium. As you are
Speaker 1: pouring energy into the medium the collection of atoms and
Speaker 1: thus exciting the electrons in those atoms to higher energy states,
Speaker 1: and when they come back down they release these photons
Speaker 1: of the same wavelength and energy level. This process happens
Speaker 1: so fast that it's really hard to wrap your mind
Speaker 1: around it all or at least, it's very hard for
Speaker 1: me to do that because we're talking about times that
Speaker 1: are at one million of a second or even shorter
Speaker 1: than that. So typically the goal is to excite electrons
Speaker 1: to an energy level two or three levels higher than
Speaker 1: their normal ground state. That increases what is called the
Speaker 1: population inversion. That is the relationship between the number of
Speaker 1: atoms that are in an excited state compared to those
Speaker 1: in the ground state. So we call it inverted because
Speaker 1: typically most atoms are in a ground state, but now
Speaker 1: we've inverted that where most atoms are in an excited state.
Speaker 1: As the electrons calm the heck down, they release these
Speaker 1: photons of the same wavelength. Since that lasing medium is
Speaker 1: obviously made out of all the same stuff, these photons
Speaker 1: are locked together, so their wavefront's launching unison. That's what
Speaker 1: makes them coherent, and they are very directional. And this
Speaker 1: happens because of the stimulated emission part of lasers. So
Speaker 1: you've got an excited electron, it returns to its ground state,
Speaker 1: it releases a photon of a certain wavelength. If that
Speaker 1: photon happens to run into an atom that also has
Speaker 1: an electron that was in that same excited state, the
Speaker 1: photon can stimulate that atom so that the photon the
Speaker 1: atom will emit when it's electron returns to its ground state,
Speaker 1: is going to vibrate the same as that first photon,
Speaker 1: and it will also move in the same direction as
Speaker 1: that first photon. Mirrors make up another important component in
Speaker 1: your typical laser. So let's think of a very simple laser.
Speaker 1: Imagine you've got a tube and this tube is your laser.
Speaker 1: On either end of the tube, you have mirrors that
Speaker 1: are facing into the tube's center, and in the middle
Speaker 1: of the tube, you've got the lazing medium and you've
Speaker 1: got a big flash lamp pointed at this tube and
Speaker 1: it can shoot extremely intense white light at the lasing medium,
Speaker 1: which then ends up inducing this this uh laser to
Speaker 1: to begin this this you know, this stimulated a mission
Speaker 1: process to begin, and so you get photons that are
Speaker 1: emitted by these excited atoms. They traveled down the tube,
Speaker 1: they hit a mirror, bounces back, and it passes through
Speaker 1: the lasing medium again and that gives it the opportunity
Speaker 1: to stimulate some more of the atoms that they too
Speaker 1: will release photons that will be in the same um wayfront,
Speaker 1: same direction as the initial photons. They'll continue down the tube,
Speaker 1: hit the mirror, bounce back, and this creates a cascade
Speaker 1: effect that can create more and more photons generating through
Speaker 1: this laser. Now, one of those two mirrors is what
Speaker 1: we would call half silvered, which means the mirror will
Speaker 1: actually allow some of that light to pass through a
Speaker 1: reflecting the rest of it back in. So some of
Speaker 1: the laser light escapes through that and then can be
Speaker 1: in a focused beam, while other photons would still bounce
Speaker 1: back into the tube and continue the propagation of photons.
Speaker 1: So that's how lasers work. From a very very high level.
Speaker 1: There are a lot of different details we could get into,
Speaker 1: like the fact that there are so many different types
Speaker 1: of lasing media like their solid state, there's gas lasing media, etcetera, etcetera.
Speaker 1: But what makes one laser more powerful than another, Well,
Speaker 1: that's a tricky question. What makes one laser a fun
Speaker 1: toy a like a laser pointer and another one powerful
Speaker 1: enough to etch metal? Well, first, the energy level of
Speaker 1: photons produced by a lasing material is inversely proportional to
Speaker 1: the wavelength of the light produced when it is stimulated.
Speaker 1: When that lasing material is stimulated, So the higher the
Speaker 1: energy of the photon, the shorter the wavelength of that photon,
Speaker 1: and the wavelengths of visible light range from around the
Speaker 1: three range that would be in the violet part of
Speaker 1: the spectrum all the way up to seven nimes which
Speaker 1: would be in the red part of the spectrum. So
Speaker 1: the further down roy g BIV you go, the higher
Speaker 1: the energy levels of the associated photons. So one thing
Speaker 1: that determines the power of a laser is the energy
Speaker 1: level of the photons, which depends upon the lasing medium
Speaker 1: and the amount of energy you're pouring into that medium
Speaker 1: to produce the laser in the first place. So your
Speaker 1: power source is another factor to consider, and there's also
Speaker 1: the question of whether your laser is constant or a
Speaker 1: pulse laser that also affects the power of the laser beam.
Speaker 1: I'll talk more about pulse lasers a little bit later
Speaker 1: in this episode because it's a very important component of
Speaker 1: the really powerful lasers we're going to talk about. So
Speaker 1: when we come back, I'm going to start talking about
Speaker 1: some of these really powerful lasers and what they're used for.
Speaker 1: But first let's take a quick break to thank our sponsor.
Speaker 1: At the University of Nebraska, there is an extreme Light laboratory,
Speaker 1: and in that lab there's an enormous device called the
Speaker 1: Diacles laser. It's named after the inventor of the parabolic reflector.
Speaker 1: The parabolic reflector increases the intensity of reflected light. It's
Speaker 1: the most efficient way of doing it, the most powerful
Speaker 1: way of increasing the intensity of selected light that we've
Speaker 1: ever discovered. So according to the labs website quote, Diacles
Speaker 1: begins with a modest amount of energy with a short pulse,
Speaker 1: then stretches the pulse and sends it through a series
Speaker 1: of amplifiers and titanium sapphire crystals to pump up its power.
Speaker 1: The secret to Diacles is high power. Is a compression
Speaker 1: stage where the stretched amplified pulse is compressed back into
Speaker 1: a very short, extremely powerful pulse. This trick prevents damage
Speaker 1: to the amplifiers. Then the powerful beam hits a parabolic
Speaker 1: reflector that focuses its power to extreme intensities. I'll go
Speaker 1: more into this approach a little bit later with one
Speaker 1: of the other lasers, but the result of this is
Speaker 1: that you get a laser beam so powerful that it
Speaker 1: reportedly can produce light that is one billion times brighter
Speaker 1: than the light produced at the surface of the Sun itself.
Speaker 1: So what would you use the kind of a laser for.
Speaker 1: Would you use it to to blast a planet into
Speaker 1: a billion pieces because it was in Alderon places rim shot. No,
Speaker 1: because that would actually require way more energy than even
Speaker 1: this beast could produce. The DIACLES is designed for scientific research,
Speaker 1: particularly in the realm of studying the interactions between light
Speaker 1: and matter. It's mostly used in an area called high
Speaker 1: field science. So what the heck is that? Well, the
Speaker 1: University of Nebraska is not the only place that does this.
Speaker 1: There's also the University of Michigan. They have a Center
Speaker 1: for Ultra Fast Optical Science. They break down high field
Speaker 1: science as science revolving around conditions that include high energy density,
Speaker 1: and that involves getting a better understanding of non equilibrium
Speaker 1: systems as well as a deeper understanding of electron behaviors.
Speaker 1: So this has the potential to have many different applications
Speaker 1: in the future relating to cool stuff nanotechnology. Plus, well,
Speaker 1: we don't even know what we don't know yet, so
Speaker 1: we might find other really nifty things to do with it.
Speaker 1: One thing, this laser can do right now? Is vapor
Speaker 1: us stuff real good? Actually, I should say it can
Speaker 1: excite matter to convert it to plasma. Plasma is the
Speaker 1: most plentiful form of matter in the universe. Matter heats
Speaker 1: up to incredible temperatures under the intensity of this laser,
Speaker 1: and it also has its pressure increased dramatically, and at
Speaker 1: that point the material converts into a gas through which
Speaker 1: free electrons can flow. That is plasma. So plasma is
Speaker 1: sort of you can think of it as almost a
Speaker 1: subtype of gas. It's more than just gas because you
Speaker 1: have this condition where you have high energy in there,
Speaker 1: so you've got a lot of free electrons flowing around.
Speaker 1: You have a typically a net neutral electric charge plasma,
Speaker 1: but it means it can actually conduct electricity itself. This
Speaker 1: is the stuff of stars. Stars are made of plasma,
Speaker 1: So you're talking incredibly high temperatures and pressures in the
Speaker 1: research team at Nebraska used this particular laser to conduct
Speaker 1: a super interesting experiment. They wanted to find out what
Speaker 1: would happen if you bombarded the same electron with numerous photons.
Speaker 1: And this is I have to stress wicked hard to do.
Speaker 1: An electron is a pretty darn tiny target. Now. I'm
Speaker 1: not going to get into the size of electrons here
Speaker 1: because that alone is a complicated issue and involves things
Speaker 1: like wave functions. But anyway, it's it's really really super small.
Speaker 1: Near typical electron rarely encounters a photon. It might get
Speaker 1: struck by a photon three times a year, so every
Speaker 1: four months or so, this electron might run into a photon,
Speaker 1: but otherwise eyes know. The team, however, wanted to pelt
Speaker 1: the heck out of electrons. They wanted to study the
Speaker 1: scatter effect that the electron would have on photons. The
Speaker 1: scatter effect is what happens when light strikes a surface.
Speaker 1: The light scatters after it hits a surface, and our
Speaker 1: eyes can pick that light up, and that's how vision works.
Speaker 1: You can see stuff because light scatters off of it
Speaker 1: in various ways. Now, the team was doing the same thing,
Speaker 1: except instead of using a general light source like a
Speaker 1: lamp and a macro sized object like say a couch
Speaker 1: or something, they were using this super powerful laser as
Speaker 1: the light source an electron beam as their target. Now,
Speaker 1: according to the University of Nebraska's newspaper, the team was
Speaker 1: able to scatter nearly one thousand photons off the same electron,
Speaker 1: and according to the team, the behavior of both the
Speaker 1: photons and the electron fell outside the normal reactions, which
Speaker 1: is pretty interesting in science. Anything that is outside the
Speaker 1: normal result is interesting. Now, if you're unlucky, if you
Speaker 1: haven't been super careful or or something has gone wrong,
Speaker 1: your observations might be indicative of an experimental error somewhere,
Speaker 1: like maybe you made a mistake, maybe some of your
Speaker 1: equipment wasn't working. But if you are lucky, you did
Speaker 1: everything properly, all your equipment works. What you were actually
Speaker 1: seeing is legitimately a new observation of a real phenomenon.
Speaker 1: So the team discovered that once laser light passed a
Speaker 1: certain power threshold, it would scatter off of electrons in
Speaker 1: interesting ways. Now, typically light from a source will scatter
Speaker 1: in a predictable way at the same angle and energy
Speaker 1: it possessed before the collision, no matter how intense the light.
Speaker 1: So think of it as a dimmer switch. If you
Speaker 1: have a dimmer switch on installed, and you're looking at
Speaker 1: say a table and low light, As you intensify the light,
Speaker 1: the table's shape doesn't change, its color doesn't change, it
Speaker 1: it brightens, so you might get more of a view
Speaker 1: of what the color is, but it doesn't change in
Speaker 1: any real phenomenal way. Uh, that was not what they
Speaker 1: were seeing. They were getting a totally different result. So
Speaker 1: if we could scale this up like their results and
Speaker 1: observe it with our eyeballs instead of with super sensitive
Speaker 1: you know, sensors, it would mean that if you were
Speaker 1: to use that same dimmer switch, you could see that
Speaker 1: as you turned the light past a certain level of intensity,
Speaker 1: the thing you're looking at that table would actually appear
Speaker 1: to change shape and color because you were using light
Speaker 1: that was of that great intensity. That's essentially what they found,
Speaker 1: except again, they weren't using diffuse light. They were using
Speaker 1: a super focused, very high powered laser, and they weren't
Speaker 1: looking at a macro object. They were looking at electrons.
Speaker 1: The team also observed that the electron being pummeled by
Speaker 1: photons would release its own photon, so the electron would
Speaker 1: become stimulated in other words, but that this ejected photon
Speaker 1: would begin to absorb the energy of the scattered photons
Speaker 1: from the laser. This transformed the energy and wavelength of
Speaker 1: the ejected photon, and it would turn into an X ray. Now,
Speaker 1: according to the researchers. Such an X ray could have
Speaker 1: useful applications in nanotechnology. The X ray only lasts for
Speaker 1: a short moment, but has an extreme amount of energy,
Speaker 1: and it could be used to help create three dimensional
Speaker 1: images of stuff on the nanoscopic scale, and that would
Speaker 1: be phenomenal because the nanoscale is so small that at
Speaker 1: the lower end of it, you're dealing with stuff that's
Speaker 1: actually smaller than the wavelength of visible light, which is
Speaker 1: why you cannot use an optical microscope to look at
Speaker 1: stuff that's on the nanoscale. The wavelengths of light are
Speaker 1: just too big to pick up the objects you're actually
Speaker 1: looking for, so that's kind of crazy. But this could
Speaker 1: potentially allow people to create three dimensional visualizations of objects
Speaker 1: that are on the scale. It could also have other
Speaker 1: practical applications, including medical ones. It could allow X ray
Speaker 1: technicians to create images at a much higher resolution, which
Speaker 1: would be really useful to look for stuff like micro fractures.
Speaker 1: For example, the standard X ray machine might not be
Speaker 1: able to detect because it wouldn't have that level of resolution.
Speaker 1: It could also be used in other applications, such as
Speaker 1: in security systems to scan for potential weapons or other
Speaker 1: security threats, and it's increasing our understanding of physics in general,
Speaker 1: which could lead to practical applications we can't even anticipate.
Speaker 1: So that's Diacles. But we have more to talk about
Speaker 1: in just a moment. Let's take a quick break to
Speaker 1: thank our sponsor. Earlier I mentioned the University of Michigan's
Speaker 1: Center for Ultra Fast Optical Science. That's the home of
Speaker 1: another incredibly powerful laser. This one is called the Hercules laser.
Speaker 1: It's a high field pedal what class laser? A pedal? What,
Speaker 1: by the way, is a billion million whats and a
Speaker 1: what corresponds to the power and electric circuit in which
Speaker 1: the potential difference is one vault and the current is
Speaker 1: one amp here. So we're talking very high energy laser here.
Speaker 1: This laser is used in the LABS research programs to
Speaker 1: quote explore the ultra relativistic intensity regime of laser matter interaction.
Speaker 1: In to quote, huh, what the heck does ultra relativistic mean?
Speaker 1: While as you might guess, it does refer to the
Speaker 1: theory of relativity, A particle is said to be ultra
Speaker 1: relativistic when it is advanced to the speed that's really
Speaker 1: close to the speed of light when you get it
Speaker 1: super super fast, about as close to the speed of
Speaker 1: lights you can possibly manage. Einstein, of course, told us
Speaker 1: the speed of light is essentially the speed limit for
Speaker 1: all the stuff in our universe. In two thousand seven,
Speaker 1: the engineering team at the University of Michigan generated a
Speaker 1: laser with the power of three hundred terra wats, and
Speaker 1: it started off an era of ultra powerful laser experiments.
Speaker 1: The team holds the world records for highest focused intensity
Speaker 1: of a laser and the amplified spontaneous emission temporal contrast.
Speaker 1: I have no idea what that second thing means, if
Speaker 1: I'm being honest, but it does sound wicked dope. Remember
Speaker 1: earlier when I talked about how a laser's power depends
Speaker 1: partly on whether it is pulsed or a constant. Well,
Speaker 1: the Hercules laser relies upon a type of amplification called
Speaker 1: chirped pulse amplification. So this gets super technical, and I,
Speaker 1: frankly I do not understand all of it. So we're
Speaker 1: gonna go super high level because that's all my primitive
Speaker 1: reptile brain can handle. I'm gonna do my best to
Speaker 1: explain it as I understand it. So many apologies to
Speaker 1: all the high high field physics experts out there, all
Speaker 1: the laser engineers out there, give me a whole lot
Speaker 1: of slacks. So the goal is to use very short
Speaker 1: pulses of energy to create this laser and then amplify
Speaker 1: those pulses to get an output energy level that typically
Speaker 1: would only come from a longer pulse of energy. Now,
Speaker 1: when I say short pulses, i'm talking crazy short. We're
Speaker 1: talking on the femto second scale. A fempto second, by
Speaker 1: the way, is one quadrillionth of a second. It's an
Speaker 1: incredibly short amount of time. The fempto second laser pulse
Speaker 1: that starts things off has a very high peak power
Speaker 1: level and as well as the other stuff that comes
Speaker 1: with that like electric fields and stuff. But these qualities
Speaker 1: actually make those super short pulses potentially harmful to laser
Speaker 1: components like optics, and it can also cause beam distortion.
Speaker 1: So your output, your goal for your output is to
Speaker 1: get the super high powered laser, but the energy representing
Speaker 1: those pulses could end up tearing apart the very components
Speaker 1: of the user that you rely upon. So here's the solution,
Speaker 1: and I mentioned it in the Diocles one as well.
Speaker 1: That description talked about this. It's using a reversible process
Speaker 1: to effectively stretch out the laser pulse for the amplifier.
Speaker 1: And when you stretch out the laser pulse, it's not
Speaker 1: just dealing with a pulse that lasts longer. The energy
Speaker 1: level is reduced as well. So the amplifier, as the
Speaker 1: name suggests, amplifies that incoming signal so that the outgoing
Speaker 1: signal is much greater. It does this by ending up,
Speaker 1: you know, the lasing medium ends up ejecting these photons,
Speaker 1: all of the same wavelength and the same energy level. Uh,
Speaker 1: and they all are going through in the same process. Now,
Speaker 1: before it actually emerges from the laser, it needs to
Speaker 1: go through another system to compress that pulse to intensify
Speaker 1: the peak power of the outgoing laser. So you're doing
Speaker 1: the reverse of the stretching process that I mentioned a
Speaker 1: second ago. And by compressing the pulse back to its
Speaker 1: original length, you also increase its peak power back to
Speaker 1: its original peak power. So such a laser has an
Speaker 1: optical stretcher and an optical compressor in order to do this.
Speaker 1: So how do those work? Beats me, I read a
Speaker 1: whole paper on it, and my brain is still buzzing.
Speaker 1: And I don't even have the beginning levels of comprehension
Speaker 1: for this. This is way outside my level of expertise. However,
Speaker 1: the outcome is that we can now build lasers with
Speaker 1: incredibly high peak power outputs that otherwise would have been impossible.
Speaker 1: So the research team has two different test chambers that
Speaker 1: the hercules can fire a laser into. One test chamber
Speaker 1: is for gases and the other one is for solids.
Speaker 1: Both chambers are surrounded by radiation shielding in the form
Speaker 1: of cement walls, but the gas chamber has a secondary
Speaker 1: level of shielding made up from lead bricks to help
Speaker 1: block any potentially harmful radiation that would result from collision experiments.
Speaker 1: The team is using this UH laser to learn more
Speaker 1: about these high powered interactions between matter and light. Some
Speaker 1: of what they learned might be useful in future applications,
Speaker 1: ranging from studying rapidly changing conditions within a plasma all
Speaker 1: the way to absorption spectroscopy, which is UH the group
Speaker 1: of methodologies we used to determine the measure of radiation
Speaker 1: absorption of various materials and hey while I've been covering
Speaker 1: some super high tech lasers that are pushing our understanding
Speaker 1: of physics into new territory. I'm gonna also mention one
Speaker 1: that might be used for less scholarly applications. That would
Speaker 1: be the Athena laser from Lockheed. This prototype laser quote
Speaker 1: uses Lockheed Martin's thirty kilowatt accelerated laser demonstration initiative, a
Speaker 1: k Aladdin spectral beam combining fiber laser in which multiple
Speaker 1: fiber laser modules form a single, powerful, high quality beam,
Speaker 1: providing great efficiency and lethality in a design that scales
Speaker 1: to higher power levels. End quote. That's terrifying, great efficiency
Speaker 1: and lethality. Now it's a prototype laser weapon system that
Speaker 1: is designed to defeat close in, low value threats such
Speaker 1: as improvised rockets, unmanned aerial systems, vehicles, and small boats.
Speaker 1: It's also a quote from Lockheed Martin. So essentially, this
Speaker 1: device can can fire an incredibly intense beam of light
Speaker 1: at a target and it has the goal of either dazzling, damaging,
Speaker 1: or destroying the target. So you're either trying to disrupt
Speaker 1: it's it's optical systems so it can't find a target
Speaker 1: or you're disabling it in some way or outright destroying it.
Speaker 1: The system relies on an infrared tracking camera to aim
Speaker 1: the laser at the target. For slower moving targets like
Speaker 1: a boat or an unmanned drone, a human operator would
Speaker 1: be allowed to verify that the target is in fact
Speaker 1: a potential threat before the system would actually fire. For
Speaker 1: more immediate threats like improvised rockets or mortars, where time
Speaker 1: is of the essence, the system would operate in an
Speaker 1: autonomous mode, and the system has been demonstrated a few times.
Speaker 1: I actually watched a video of the Athena targeting system
Speaker 1: and watched as it brought down a drone that was
Speaker 1: designed to look kind of like your standard aircraft had
Speaker 1: wings and a tail section. So Athena would target the
Speaker 1: stabilizing fin on the tail of this unmanned aerial drone
Speaker 1: and using this very high powered laser, it damaged the fin,
Speaker 1: actually burned the fin off in a couple of examples
Speaker 1: pretty quickly, and that caused the drone to plummet to
Speaker 1: the earth and lock. It has also shown that such
Speaker 1: a laser could even melt clean through the engine blow
Speaker 1: of a truck. Now the prototype is a proof of concept,
Speaker 1: and this laser isn't anywhere close to being a handheld weapon.
Speaker 1: This is not something you would give a soldier and
Speaker 1: say head out there and take down that tank. It's
Speaker 1: a pretty big device. It would fit on like a warship,
Speaker 1: but it would require some mantorization to fit on a
Speaker 1: tank or truck and not be so cumbersome and heavy
Speaker 1: that it would make operating the vehicle difficult. So we've
Speaker 1: got a long way to go before this gets deployed
Speaker 1: anywhere beyond very very large platforms, like I said, like
Speaker 1: on warships or something. Still, this could be an indication
Speaker 1: pointing toward the future of warfare where weapons work at
Speaker 1: the speed of light and can burn through solid steel
Speaker 1: in a matter of moments. But while there are destructive
Speaker 1: uses for powerful lasers, a lot of the ones I've
Speaker 1: looked at are meant to conduct scientific research or directly
Speaker 1: help with goals like making a practical fusion reactor or
Speaker 1: majorizing particle accelerators so that you don't have to build
Speaker 1: a facility the size of the large hadron collider in Europe.
Speaker 1: So there are a lot of scientific, constructive methods and
Speaker 1: uses for lasers. So I'm very interested to learn more
Speaker 1: about those and maybe someday getting a better grasp on
Speaker 1: some of the more complicated factors like the lazing methodologies
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