December 16, 2024 • 17 mins
New and advanced lasers are necessary to understand the complicated high energy, fast bursts of light occurring at the most extreme conditions in the universe. Franklin Dollar, professor of physics and astronomy at the University of California, Irvine, discusses lasers, how they're used to understand physics and how powerful the next generation of lasers will be.
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(00:03):
This is the Discovery Files podcastfrom the U.S.
National Science Foundation.
At the frontiers of Astrophysics.
New and advanced technologies arenecessary to understand the complicated,
high energy, fast bursts of lightoccurring at the most extreme conditions
in the universe.
Our guest today is Franklin Dollar,professor of physics and astronomy
(00:25):
and associate dean of graduate studiesin the School of Physical Sciences
at University of California, Irvine,who works with lasers
to understand how high intensitylight interacts with matter.
Professor Dollar,thank you for joining us again.
I'd like to startwith a real general overview question.
What is a laser?
So you can think of a laseras a sort of light photocopier.
(00:48):
So one ray of light will come inand you'll get two rays of light
that come out in a way that makes it
almost a perfect copy of itself.
And we normally maybe don't think of lightlike that.
I might have like a light bulb or a lightthat's coming at me
like this, and it may look likeit's all the same kind of light.
(01:09):
It's all white light.
But actually,the way that the light's hitting me
is it's coming fromlots of different directions.
There could be lots of different colorsthat are coming from this
light bulb to me.
And so it's actually a big mix of light.
How when the light comes from that lightbulb to me could be random.
So in a way, when that light gets to me,it's actually kind of a random mess.
(01:30):
Whereas the laser, everything's perfect.
So you can start with one ray.You get two rays.
Those two rays, you make a copy of them.
Now you have four rays.
You takethose four rays may have eight rays,
and they're perfectly identicalin every way, shape or form.
You were talkingabout different kinds of light.
What makes laser light special?
One way to think aboutit might be to imagine, you know, the air
(01:53):
that's around us.
So most of the time we don't thinkanything about the air around us.
You can ignore it.You could wave your hands around.
You can treat itas if nothing was there at all.
But actually, there's tons of atomsall around us, and they're zipping around.
Actually moving quite fast.
Something like a thousand miles an hour.
And we don't feel thingsmove like a thousand miles an hour
(02:15):
hitting us, because all of the airthat's surrounding us is random.
The directions are random.The motion is random.
It's hitting us at different times.
So we don't really notice it that much.
But now imagine that if I had all the airin the room and instead of bouncing
around randomly, it started to go more inone direction than another.
We have wind.
(02:36):
And so you can tell the differencefrom having some amount of directionality
in the air that you didn't have before.
And if you had all of the atoms
they moved in exactly the same direction,
then this would be strongerthan any hurricane wind you'd ever have.
And again,all these air molecules are moving around
at a thousand miles an hour, butthey're normally running into other air
(02:58):
molecules,and you don't actually feel that.
But if you could just point
all of them in the same direction,make perfect copies of them.
Then it would justknock you off your feet.
And that's kind of the analogI like to think of with the laser.
When we have something like a light bulb,we have like the air in the room.
And so it's hittingyou all kind of randomly.
(03:18):
But if you have laser, it'sthe same air, it's the same light,
but it's all coming at the same timeand it's all with the same direction.
And it's a lot easier to understandbecause now everything is moving
the same way.
So you can work with it in a way
that you just couldn'timagine working with it before.
Another different kinds of lasers.
I've heard of liquid based onesand crystals.
(03:41):
What are lasers made out of?
So you can make a laser outof almost anything?
As long as a certain number of conditionsare met, the material itself
needs to want to producethe same kind of light that goes into it.
And so different types of elementstogether
or preferto make different kinds of light.
(04:02):
But the material itself really definesthe colors of light it wants to amplify.
In many cases,you could have a laser out of a gas.
So this might be a CO2 laser,or it could be a very common
laser, would be a helium neon laser,which is a gas that exists in a tube.
And you can go ahead and use thatas a laser.
(04:22):
It's a very common laser that's used to.
But some of the difficulties that we have,whether we use a gas or a liquid,
is that they're kind of awkward substancesto work with.
You know, if you have a gasand you need to make sure it doesn't leak.
Same thing with the liquid.
So in a lot of more common placesthat you may see some lasers,
we like to move things to solid state,something like a crystal
(04:45):
where we can manufacture themvery nicely and precise.
And they're just sit there.
You don't need to worry about itleaking or doing anything like that.
So these solid state lasersthat are just maybe a block of glass
or a block of crystalthat we can just sit there
and manufactureto be exactly what we need,
are kind of the easiest systemsfor us to work with for lasers.
(05:09):
There's a lot of different kinds of lasersin movies and TV.
What are some of the waysyou work with lasers in real life?
One of the most interesting aspects I findis that when the laser was created,
we have this light
and we know everything about it,and it's got this well-defined direction.
And from a physics point of view,it's beautiful because we can write
(05:29):
an equation and the light is doingeverything in this equation.
It's not even just an approximation.
It really is what this equation is.
So as a physicist, we love that
this perfect matchbetween our math and the real world.
But then it was thought of as a solutionin search of a problem.
It's like great.
So you write the math.What can you do with it?
(05:50):
And this is actually what I think is,is kind of the power of basic research
and understanding is onceyou really understand
what the light can doand you can write this equation for it,
then reallyyour imagination is the only limit.
And now of course,we see lasers in all kinds of things.
So we see lasers,you know, at the supermarket
where they can scan a QR code.
(06:11):
But we also have technology where we havelasers that can go ahead and do surgery
because you can focus light downtighter than you can with a scalpel.
You can go ahead and use lasersfor manufacturing.
You can dowelding in incredibly more precise
and efficient waysthat you couldn't do before.
You can use lasers to see out into space.
(06:35):
And so, for instance,we can focus the laser
very high in the atmosphereto make it look like a star.
And because we know exactly where it isand how we made it,
it tells us what the atmosphere looks liketo go through there to make that star.
So now we can see in the spacebetter from Earth
because we knowwhat the atmosphere is doing.
(06:57):
We can go ahead and put thisin autonomous vehicles,
because now we know the lightperfectly well.
We can go ahead and see how far awayeverything is.
In the list just keeps going on.
Because once you have a foundational basisto be able to describe everything
you're working with, you really canjust apply it wherever you can.
Now we have a laser pointercat toy at home, and I've noticed
(07:19):
it has classification informationon the side of it.
And I'm wondering
if you could tell me what does that meanand how are lasers classified?
This is a very interesting question.
So one, there's,you know, a safety level of classification
that we use to describe lasers,whether you can hurt yourself with it.
And then once you go upto a high enough level,
(07:40):
whether you can hurt other people with it,and when you go up to a higher level,
whether you can always hurtsomeone with it
and it turns out that'swhere the thresholding stops.
And and so you can have a laser pointerthat meets the highest threshold.
And then we can also have a laserthat can go ahead and instigate fusion.
And so both of those are in the samecategory or classification of laser.
(08:01):
But we can think ofsomething like a laser pointer.
This is maybe a laserthat many people have seen.
Certainlyif they're seeing physics professors,
they probably comeacross the laser pointer once or twice.
And so this is a remarkable device laserthat you can hold in your hand.
It puts out very little energy in termsof the light that comes out of it.
So we may have something like a ten wattlight bulb.
(08:23):
This laser pointer will be putting outsomething maybe like five milliwatts.
So a thousand times less lightthat's coming out of this.
So if I take this laser pointer
and point it,even though it's such a small amount of
energy and a small amount of powercoming out of this thing, it looks very,
very bright because all the lightscoming out exactly the same way.
(08:46):
So if I go back to the analog
of the gas molecules in the room,
I can ignore them, even thoughthey're moving a thousand miles an hour.
But if even a small fraction of themare all pointing
in the same direction towards my face,I certainly would notice it.
Same thing with this laser pointer.
So now what's really interestingis that there's kind of two ways
(09:07):
you can go ahead about making this lasermore intense.
One way is to addmore and more energy to it.
And so this means that as I'm holdingmy laser,
it's putting more and more light energyout over time.
And that's a knob.
You can only turn so muchbefore you start needing a power plant
to go ahead and provide that much lightcome out of it.
(09:28):
But there's actually another wayto make this laser more intense,
and that's by having a pulsed laser.
Power is defined as a rate.
It's how much energy you get per time.
I might have a camera flash,
and there's not going to bethat much energy released,
but it seems very bright becauseAll the Light was released very quickly.
(09:52):
So if I am allowed to go back to this
analog with the gas moleculesone more time, if I had all the air
molecules moving at 1000 miles an hourtowards my face, that would be pretty bad.
But if all of them hit my face at exactlythe same time, that would push me back
way farther than if it were spread outover a long period of time.
(10:13):
And that's a way of makingthis more intense.
A more powerful laser is,if I take that same amount of light,
but instead of slowly distributingthat light over the course
of something like a second, I pulse it.
I deliver the same amount of lightin a smaller period of time.
So if I go back to this laser pointor something like a five milliwatts
(10:36):
laser pointer,and I take the energy in that
and now I deliver in half the time,I've made it twice as powerful.
And if I deliver it inone tenth at a time, so 100 milliseconds,
I've made it ten times more powerful.
So now, instead of being a 5,000,000 wattlaser, it's a 50 watt phaser.
(10:57):
And now I could think of what would happenif I took this five milliwatts
laser light.
And instead of spreading it outover a second, I deliver
in a millionth of a billionth of a second.
Then I would have a laserthat is a million,
billion times more powerful.
(11:17):
Then I started off with the same energy,
but so muchmore powerful and so much more intense.
And these are the lasersthat we like to use
in my field, and the lasersthat are the technology
of chirped pulse amplification,which won the 2018 Nobel Prize.
And what is the underlying technologyfor systems
(11:39):
such as the NSF Zeus Laser Facilityand the NSF Overall Laser facility?
Speaking of those laser facilities,since the last time you joined us a year
ago, you've carried out the firstofficial experiment on the NSF ZFS laser.
I know you haven't published results yet,
but can you tell us a little bitabout your experience with that?
Yeah,so we performed the first experiments
(12:00):
at ZFSusing their kind of flagship capability.
So using the so-called Petafloppeak powers.
So this is turning ZFS upto a thousand terawatts.
And for comparison, a terawatt is roughly
how much the US power gridis using at any given moment.
And so if you can imagineharnessing the entire U.S.
(12:22):
power grid,
multiplying it by a factor of a thousand,
using that to do science experiments,that's what we're talking about here.
And it only exists for a very, very,
very short period of time,millions of a billionth of a second.
But the power is so highthat you can really just make
very extreme conditions that you wouldn'tbe able to see otherwise.
(12:43):
And so in our first experimentsthat we've been able to perform out there,
we're just shy of a pedal watt.
So I think the power that we were using
was somewherein the order of 800 terawatts or so.
And when Zeus's is fully ramped up,it will be 3000
terawatts or three peda watts.
(13:03):
These are very big numbers and even so fargoing up, not even a factor of ten.
In terms of the power,we've been able to go ahead and increase
the amount of energythat we're seeing in the electron beams
that we're producinggo up by a factor of ten.
So our acceleratedelectron beams were somewhere in the order
(13:24):
of a few hundred MeVbefore now, we've been able to see
2 to 3 GeV electronbeams get produced from the interaction.
Now, what kind of applications cana powerful laser like ZEUS be used for?
One of the applicationsthat we can use ZEUS for
is to make a compact particle accelerator.
(13:44):
So you might think of somethinglike the big machine
that we have over in Geneva,the CERN accelerator,
and we use it to accelerate particlesto very, very close to the speed of light.
What we're looking at is ways of doingthat with the light itself.
So by focusing the light down,making the particle accelerator,
(14:06):
that instead of being somethinglike 100km wide,
we can make somethingthat's on the order of centimeters.
And so by using ZEUS
and using an acceleratorthat's basically the size of my thumb,
we've been able to go aheadand make very energetic electron beams,
kind of comparableto what you'd see with a couple kilometer
(14:28):
machine with conventional technology.
You mentioned power factors,and I know you're a co-pi on NSF OPAL,
what is the goal of that project?
So an NSF Opal, there are two big thingsthat are happening.
One is we're pushing up that power.
Another factor of ten,the NSF Zeus facility
(14:51):
will be the most powerful laserin the United States at three petaflops.
So this is three times ten to the 15 or
3,000,000 billion watts very high wattage.
They're very high power.
This would be another factor of ten more.
So this is a laser that's 25 petaflops.
(15:11):
Having that much power allows usto make the intensities go up higher,
to look at very new,
interesting machines that we just aren'table to access with less powerful lasers.
But there's
something elsethat we're aiming for with Opal as well.
And that's
we've spent all of this time and effortmaking the most powerful laser.
(15:34):
And at 25 petaflops, this will bethe most powerful laser in the world.
When we focus that lighton, we can make incredible
extreme conditions that can makesome of the highest energy electrons
or do incredible
studies in quantum electrodynamics
(15:55):
and very high energy ion beams,
incredible compact radiation sources.
What would be excellent is if we can make
a second opal interact with those beams,
because if we think of the facilityat CERN.
What makes it interestingis that it collides the beams together.
(16:18):
And so far, we've really been focusingon what we can do with one big laser.
The unique aspect of Opal isthat we'll have two of these beams
that are able to make these
very extreme conditionsthat can then interact with each other.
And now we can look at eventsthat we think only occur
in some most extremeconditions of the universe.
(16:40):
So very interestinglaboratory astrophysics experiments
that we've never been able to do on Earthbefore.
We can now studydifferent types of nuclear physics,
different types of new particleacceleration schemes that we just aren't
able to explore because all of the laserenergy went into that one beam.
(17:01):
And so there's
just so many new opportunitiesthat we can access
by just being able to control,not just where we put the light,
but how we put that light in spaceand time relative to each other.
Special thanks to Franklin Dollar,Jeremiah Williams and Slava Lukin.
For the Discovery Files, I’m Nate Pottker.
(17:22):
You can watch video versions
of these conversations on our YouTubechannel by searching @NSFscience.
Please subscribe wherever you get podcastsand if you like our program,
share with a friend and considerleaving a review.
Discover how the U.S.
National Science Foundationis advancing research at NSF.gov.
This is the Discovery Files podcastfrom the U.S.
National Science Foundation.
At the frontiers of Astrophysics.
New and advanced technologies arenecessary to understand the complicated,
high energy, fast bursts of lightoccurring at the most extreme conditions
in the universe.
Our guest today is Franklin Dollar,professor of physics and astronomy
(00:25):
and associate dean of graduate studiesin the School of Physical Sciences
at University of California, Irvine,who works with lasers
to understand how high intensitylight interacts with matter.
Professor Dollar,thank you for joining us again.
I'd like to startwith a real general overview question.
What is a laser?
So you can think of a laseras a sort of light photocopier.
(00:48):
So one ray of light will come inand you'll get two rays of light
that come out in a way that makes it
almost a perfect copy of itself.
And we normally maybe don't think of lightlike that.
I might have like a light bulb or a lightthat's coming at me
like this, and it may look likeit's all the same kind of light.
(01:09):
It's all white light.
But actually,the way that the light's hitting me
is it's coming fromlots of different directions.
There could be lots of different colorsthat are coming from this
light bulb to me.
And so it's actually a big mix of light.
How when the light comes from that lightbulb to me could be random.
So in a way, when that light gets to me,it's actually kind of a random mess.
(01:30):
Whereas the laser, everything's perfect.
So you can start with one ray.You get two rays.
Those two rays, you make a copy of them.
Now you have four rays.
You takethose four rays may have eight rays,
and they're perfectly identicalin every way, shape or form.
You were talkingabout different kinds of light.
What makes laser light special?
One way to think aboutit might be to imagine, you know, the air
(01:53):
that's around us.
So most of the time we don't thinkanything about the air around us.
You can ignore it.You could wave your hands around.
You can treat itas if nothing was there at all.
But actually, there's tons of atomsall around us, and they're zipping around.
Actually moving quite fast.
Something like a thousand miles an hour.
And we don't feel thingsmove like a thousand miles an hour
(02:15):
hitting us, because all of the airthat's surrounding us is random.
The directions are random.The motion is random.
It's hitting us at different times.
So we don't really notice it that much.
But now imagine that if I had all the airin the room and instead of bouncing
around randomly, it started to go more inone direction than another.
We have wind.
(02:36):
And so you can tell the differencefrom having some amount of directionality
in the air that you didn't have before.
And if you had all of the atoms
they moved in exactly the same direction,
then this would be strongerthan any hurricane wind you'd ever have.
And again,all these air molecules are moving around
at a thousand miles an hour, butthey're normally running into other air
(02:58):
molecules,and you don't actually feel that.
But if you could just point
all of them in the same direction,make perfect copies of them.
Then it would justknock you off your feet.
And that's kind of the analogI like to think of with the laser.
When we have something like a light bulb,we have like the air in the room.
And so it's hittingyou all kind of randomly.
(03:18):
But if you have laser, it'sthe same air, it's the same light,
but it's all coming at the same timeand it's all with the same direction.
And it's a lot easier to understandbecause now everything is moving
the same way.
So you can work with it in a way
that you just couldn'timagine working with it before.
Another different kinds of lasers.
I've heard of liquid based onesand crystals.
(03:41):
What are lasers made out of?
So you can make a laser outof almost anything?
As long as a certain number of conditionsare met, the material itself
needs to want to producethe same kind of light that goes into it.
And so different types of elementstogether
or preferto make different kinds of light.
(04:02):
But the material itself really definesthe colors of light it wants to amplify.
In many cases,you could have a laser out of a gas.
So this might be a CO2 laser,or it could be a very common
laser, would be a helium neon laser,which is a gas that exists in a tube.
And you can go ahead and use thatas a laser.
(04:22):
It's a very common laser that's used to.
But some of the difficulties that we have,whether we use a gas or a liquid,
is that they're kind of awkward substancesto work with.
You know, if you have a gasand you need to make sure it doesn't leak.
Same thing with the liquid.
So in a lot of more common placesthat you may see some lasers,
we like to move things to solid state,something like a crystal
(04:45):
where we can manufacture themvery nicely and precise.
And they're just sit there.
You don't need to worry about itleaking or doing anything like that.
So these solid state lasersthat are just maybe a block of glass
or a block of crystalthat we can just sit there
and manufactureto be exactly what we need,
are kind of the easiest systemsfor us to work with for lasers.
(05:09):
There's a lot of different kinds of lasersin movies and TV.
What are some of the waysyou work with lasers in real life?
One of the most interesting aspects I findis that when the laser was created,
we have this light
and we know everything about it,and it's got this well-defined direction.
And from a physics point of view,it's beautiful because we can write
(05:29):
an equation and the light is doingeverything in this equation.
It's not even just an approximation.
It really is what this equation is.
So as a physicist, we love that
this perfect matchbetween our math and the real world.
But then it was thought of as a solutionin search of a problem.
It's like great.
So you write the math.What can you do with it?
(05:50):
And this is actually what I think is,is kind of the power of basic research
and understanding is onceyou really understand
what the light can doand you can write this equation for it,
then reallyyour imagination is the only limit.
And now of course,we see lasers in all kinds of things.
So we see lasers,you know, at the supermarket
where they can scan a QR code.
(06:11):
But we also have technology where we havelasers that can go ahead and do surgery
because you can focus light downtighter than you can with a scalpel.
You can go ahead and use lasersfor manufacturing.
You can dowelding in incredibly more precise
and efficient waysthat you couldn't do before.
You can use lasers to see out into space.
(06:35):
And so, for instance,we can focus the laser
very high in the atmosphereto make it look like a star.
And because we know exactly where it isand how we made it,
it tells us what the atmosphere looks liketo go through there to make that star.
So now we can see in the spacebetter from Earth
because we knowwhat the atmosphere is doing.
(06:57):
We can go ahead and put thisin autonomous vehicles,
because now we know the lightperfectly well.
We can go ahead and see how far awayeverything is.
In the list just keeps going on.
Because once you have a foundational basisto be able to describe everything
you're working with, you really canjust apply it wherever you can.
Now we have a laser pointercat toy at home, and I've noticed
(07:19):
it has classification informationon the side of it.
And I'm wondering
if you could tell me what does that meanand how are lasers classified?
This is a very interesting question.
So one, there's,you know, a safety level of classification
that we use to describe lasers,whether you can hurt yourself with it.
And then once you go upto a high enough level,
(07:40):
whether you can hurt other people with it,and when you go up to a higher level,
whether you can always hurtsomeone with it
and it turns out that'swhere the thresholding stops.
And and so you can have a laser pointerthat meets the highest threshold.
And then we can also have a laserthat can go ahead and instigate fusion.
And so both of those are in the samecategory or classification of laser.
(08:01):
But we can think ofsomething like a laser pointer.
This is maybe a laserthat many people have seen.
Certainlyif they're seeing physics professors,
they probably comeacross the laser pointer once or twice.
And so this is a remarkable device laserthat you can hold in your hand.
It puts out very little energy in termsof the light that comes out of it.
So we may have something like a ten wattlight bulb.
(08:23):
This laser pointer will be putting outsomething maybe like five milliwatts.
So a thousand times less lightthat's coming out of this.
So if I take this laser pointer
and point it,even though it's such a small amount of
energy and a small amount of powercoming out of this thing, it looks very,
very bright because all the lightscoming out exactly the same way.
(08:46):
So if I go back to the analog
of the gas molecules in the room,
I can ignore them, even thoughthey're moving a thousand miles an hour.
But if even a small fraction of themare all pointing
in the same direction towards my face,I certainly would notice it.
Same thing with this laser pointer.
So now what's really interestingis that there's kind of two ways
(09:07):
you can go ahead about making this lasermore intense.
One way is to addmore and more energy to it.
And so this means that as I'm holdingmy laser,
it's putting more and more light energyout over time.
And that's a knob.
You can only turn so muchbefore you start needing a power plant
to go ahead and provide that much lightcome out of it.
(09:28):
But there's actually another wayto make this laser more intense,
and that's by having a pulsed laser.
Power is defined as a rate.
It's how much energy you get per time.
I might have a camera flash,
and there's not going to bethat much energy released,
but it seems very bright becauseAll the Light was released very quickly.
(09:52):
So if I am allowed to go back to this
analog with the gas moleculesone more time, if I had all the air
molecules moving at 1000 miles an hourtowards my face, that would be pretty bad.
But if all of them hit my face at exactlythe same time, that would push me back
way farther than if it were spread outover a long period of time.
(10:13):
And that's a way of makingthis more intense.
A more powerful laser is,if I take that same amount of light,
but instead of slowly distributingthat light over the course
of something like a second, I pulse it.
I deliver the same amount of lightin a smaller period of time.
So if I go back to this laser pointor something like a five milliwatts
(10:36):
laser pointer,and I take the energy in that
and now I deliver in half the time,I've made it twice as powerful.
And if I deliver it inone tenth at a time, so 100 milliseconds,
I've made it ten times more powerful.
So now, instead of being a 5,000,000 wattlaser, it's a 50 watt phaser.
(10:57):
And now I could think of what would happenif I took this five milliwatts
laser light.
And instead of spreading it outover a second, I deliver
in a millionth of a billionth of a second.
Then I would have a laserthat is a million,
billion times more powerful.
(11:17):
Then I started off with the same energy,
but so muchmore powerful and so much more intense.
And these are the lasersthat we like to use
in my field, and the lasersthat are the technology
of chirped pulse amplification,which won the 2018 Nobel Prize.
And what is the underlying technologyfor systems
(11:39):
such as the NSF Zeus Laser Facilityand the NSF Overall Laser facility?
Speaking of those laser facilities,since the last time you joined us a year
ago, you've carried out the firstofficial experiment on the NSF ZFS laser.
I know you haven't published results yet,
but can you tell us a little bitabout your experience with that?
Yeah,so we performed the first experiments
(12:00):
at ZFSusing their kind of flagship capability.
So using the so-called Petafloppeak powers.
So this is turning ZFS upto a thousand terawatts.
And for comparison, a terawatt is roughly
how much the US power gridis using at any given moment.
And so if you can imagineharnessing the entire U.S.
(12:22):
power grid,
multiplying it by a factor of a thousand,
using that to do science experiments,that's what we're talking about here.
And it only exists for a very, very,
very short period of time,millions of a billionth of a second.
But the power is so highthat you can really just make
very extreme conditions that you wouldn'tbe able to see otherwise.
(12:43):
And so in our first experimentsthat we've been able to perform out there,
we're just shy of a pedal watt.
So I think the power that we were using
was somewherein the order of 800 terawatts or so.
And when Zeus's is fully ramped up,it will be 3000
terawatts or three peda watts.
(13:03):
These are very big numbers and even so fargoing up, not even a factor of ten.
In terms of the power,we've been able to go ahead and increase
the amount of energythat we're seeing in the electron beams
that we're producinggo up by a factor of ten.
So our acceleratedelectron beams were somewhere in the order
(13:24):
of a few hundred MeVbefore now, we've been able to see
2 to 3 GeV electronbeams get produced from the interaction.
Now, what kind of applications cana powerful laser like ZEUS be used for?
One of the applicationsthat we can use ZEUS for
is to make a compact particle accelerator.
(13:44):
So you might think of somethinglike the big machine
that we have over in Geneva,the CERN accelerator,
and we use it to accelerate particlesto very, very close to the speed of light.
What we're looking at is ways of doingthat with the light itself.
So by focusing the light down,making the particle accelerator,
(14:06):
that instead of being somethinglike 100km wide,
we can make somethingthat's on the order of centimeters.
And so by using ZEUS
and using an acceleratorthat's basically the size of my thumb,
we've been able to go aheadand make very energetic electron beams,
kind of comparableto what you'd see with a couple kilometer
(14:28):
machine with conventional technology.
You mentioned power factors,and I know you're a co-pi on NSF OPAL,
what is the goal of that project?
So an NSF Opal, there are two big thingsthat are happening.
One is we're pushing up that power.
Another factor of ten,the NSF Zeus facility
(14:51):
will be the most powerful laserin the United States at three petaflops.
So this is three times ten to the 15 or
3,000,000 billion watts very high wattage.
They're very high power.
This would be another factor of ten more.
So this is a laser that's 25 petaflops.
(15:11):
Having that much power allows usto make the intensities go up higher,
to look at very new,
interesting machines that we just aren'table to access with less powerful lasers.
But there's
something elsethat we're aiming for with Opal as well.
And that's
we've spent all of this time and effortmaking the most powerful laser.
(15:34):
And at 25 petaflops, this will bethe most powerful laser in the world.
When we focus that lighton, we can make incredible
extreme conditions that can makesome of the highest energy electrons
or do incredible
studies in quantum electrodynamics
(15:55):
and very high energy ion beams,
incredible compact radiation sources.
What would be excellent is if we can make
a second opal interact with those beams,
because if we think of the facilityat CERN.
What makes it interestingis that it collides the beams together.
(16:18):
And so far, we've really been focusingon what we can do with one big laser.
The unique aspect of Opal isthat we'll have two of these beams
that are able to make these
very extreme conditionsthat can then interact with each other.
And now we can look at eventsthat we think only occur
in some most extremeconditions of the universe.
(16:40):
So very interestinglaboratory astrophysics experiments
that we've never been able to do on Earthbefore.
We can now studydifferent types of nuclear physics,
different types of new particleacceleration schemes that we just aren't
able to explore because all of the laserenergy went into that one beam.
(17:01):
And so there's
just so many new opportunitiesthat we can access
by just being able to control,not just where we put the light,
but how we put that light in spaceand time relative to each other.
Special thanks to Franklin Dollar,Jeremiah Williams and Slava Lukin.
For the Discovery Files, I’m Nate Pottker.
(17:22):
You can watch video versions
of these conversations on our YouTubechannel by searching @NSFscience.
Please subscribe wherever you get podcastsand if you like our program,
share with a friend and considerleaving a review.
Discover how the U.S.
National Science Foundationis advancing research at NSF.gov.
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