The US has a new most powerful laser hitting 2 petawatts
95 comments
·May 21, 2025owenversteeg
killjoywashere
Fun fact: these laser pulses are so short they are no longer a single wavelength. They have a spectrum due to the uncertainty principle. And at this short of a time scale, it’s pretty broad.
ta1243
The article said 2 Petawatts for 25 quintillionths of a second. That's about 50mJ.
That's about the amount of power used in your phone's flash when taking a picture, not a few seconds, but the LED being on for about 50-100 milliseconds.
owenversteeg
Not sure if the article is accurate (the accuracy of numbers in written text took a nosedive concurrent with the rise of LLMs), but the capabilities page of the laser’s website claims 23 femtoseconds pulse duration, 2 PW power, 50 J energy, and 1 shot per minute. 50 J is roughly a 3W light for 15 seconds.
mschuster91
> Not sure if the article is accurate (the accuracy of numbers in written text took a nosedive concurrent with the rise of LLMs)
Written text accuracy took a nosedive in the early '00s as newspapers couldn't afford to hire journalists with a scientific background, followed by universities not hiring scientists to write press releases any more. GIGO - garbage in, garbage out.
rl3
>And if you want the most destructive power, those are all military lasers. Which can absolutely destroy things science fiction style, but on a fairly small scale and with some important limitations.
https://en.wikipedia.org/wiki/Project_Excalibur
Once upon a time we tried developing a nuclear-pumped X-ray laser for use in strategic defense, which if my napkin math is correct was probably in the neighborhood of NIF in terms of energy output (despite the conversion efficiency being terrible). Notable is that NIF continues existing after it fires.
doctorwho42
Also NIF is actually 192 laser beams with about 3 football fields of lab grade warehouse to house all those laser beams optics for beam pumping, shaping, etc.
Not sure you can move NIF like you would move excalibur
dmurray
Finally, a use for aircraft carriers.
yongjik
> completely destroy the University of Michigan in spectacular fashion
Sure, Ann Arbor may be destroyed, but that's a sacrifice I'm willing to make. For Science. /insert Lord Farquaad meme here
null
reaperducer
Laser facilities like this one are designed for incredibly short pulses that are femtoseconds long
"Look at the facts. Very high power, portable, limited firing time, unlimited range. All you'd need is a big spinning mirror and you could vaporize a human target from space."
babyent
So.. We just need to figure out wormholes and make an infinite loop the laser goes through and harness its true power!!
Dylan16807
I understand that you're being silly, but even in this silly theory land how is that supposed to work? While the laser is in a loop it's not hitting anything, and if you let it out it's the same as when you put it in.
z2
I figure it's a matter of stacking/charging the laser in that loop with a lot of pulses, then letting that all out at once? Like, what if we shot pulses into the orbit of a mini black hole, but then managed to unwind it back out into a single direction?
babyent
You're right, I am being silly because I am too uneducated to really make sense of any of it.
I love smart people who work on this stuff, a lot of what I take for granted is due to their efforts :)
spookie
For anyone interested, the most powerful one is in Romania at the Extreme Light Infrastructure (ELI) in Măgurele. It's about 10 petawatts.
int0x29
> “Having a national resource like this, which awards time to users whose experimental concepts are most promising for advancing scientific priorities, is really bringing high-intensity laser science back to the U.S.”
Try not to deport the researchers or slash federal research funding if you really want that. Although at this point the US's reputation is damaged enough that getting and retaining researchers may be challenging.
Its a bit depressing how little universities are doing to stand up to the removal of their students
perihelions
That's a howler of a line indeed, given the NSF was slashed >50% just weeks ago (the federal agency funding this physics research).
frollogaston
This doesn't really have anything to do with the article
perihelions
I can't steelman the position that "the topic of the article might disappear at any moment because of funding cuts" is unrelated to the article. If it were a post about a startup releasing a new product, and the top comment was "hey FYI, this startup has filed for Chapter 11 bankruptcy", would that be off-topic too?
And: the article itself puffs about how this is attracting physics research to the US; how can contradicting claims the article makes be off-topic to discussion about self-same article? It can't be a "they're allowed to speak but we're not allowed to contradict"—this is HN! Discussion is the whole point!
lostlogin
That university has made cuts due to Trump policies and the funding for that laser has come from The National Science Foundation, which has had its funding cut.
https://theconversation.com/unprecedented-cuts-to-the-nation...
lurk2
[flagged]
oldpersonintx2
[flagged]
anoncow
I don't think it is. US is at risk of no longer being the right place to do research.
lurk2
Which researchers have been deported?
Jabbles
lurk2
> In one, a kidney transplant specialist at Brown University in Providence, Rhode Island, was deported to Lebanon after trying to re-enter the United States with a valid visa. It was later reported that pictures on her phone had linked her with Hezbollah, which US authorities consider a foreign terrorist organization.
This is the only example in the article.
cnees
I got a tour of the lab during construction. As a software engineer, what I found most incredible about the project was how well they stuck to their delivery proposal and timeline over the course of five years of development.
torcete
In this very interesting video, a Russian drone developer gives his thoughts about laser weapons. In theory they work, they test it always on ideal atmospheric conditions. In practice, they don't.
baxtr
Instead of petawatts I’d love to hear what it can destroy.
I imagine a scale like:
1: Mosquito
…
10000: Planet (Death Star)
vlmutolo
To kill a mosquito, you need "a few tens of millijoules, delivered within a few milliseconds" [0], so let's say 10W. To destroy the Earth (so that it turns into scattered dust and never reforms) you need about 10^32 J [1]; if we assume this is applied over maybe 100s, the laser would be 10^30W.
So the log10 scale goes from 1–30, where mosquitos die at 1 and the Earth dies at 30. The 2 PW in the article is about a 15.3. The Vulcan 20-20 project (set to complete in 2029) will register at about 20PW, or a 16.3 on the mosquito-Death Star scale [2].
So on a log scale, we're over halfway to building the Death Star.
[0]: https://spectrum.ieee.org/backyard-star-wars
[1]: https://www.scientificamerican.com/article/how-much-energy-w...
[2]: https://news.sky.com/story/worlds-most-powerful-laser-to-be-...
Dylan16807
If we're comparing lasers that go for seconds and lasers that go for femtoseconds, I think measuring watts is way too misleading.
Measured in simple joules, mosquito is .04, earth is 10^32, and this laser is 50.
If we make a joules version of the 1-30 scale, the laser in the article would only score a 4.
Hikikomori
So I could kill all the mosquitoes in my yard in one pulse with this laser.
SamBam
> if we assume this is applied over maybe 100s
I think this is the crux of the assumption right here. It sounds like this is apply for well under a nanosecond.
I think we're closer to maybe killing a mosquito than "half way to building a Death Star on a log scale" (which, I guess is already much closer to a mosquito than a planet).
beAbU
Every step is a doubling of the previous step, no?
So true "half way to a death star" is step 29/30?
hnuser123456
They used log10, so each step is 10x the previous, so in a linear sense, it would double when going from about 29.7 to 30. But it seems that humans tend to improve tech at exponential rates, where we are constantly making improvements here and there that keep stacking up, when it comes to things that are actually in a developmental stage anyways.
Say your "endstage" goal is GPU with 200 billion transistors. Using linear scale, the current biggest GPU is only halfway there, and it took all of human civilization to get this far, and it will take another civilization to get to 200b. In reality, we'll have that in a couple years with our current civilization.
baxtr
This is awesome! Thank you!!
I’m still not sure what 15.3 on the MDS scale can destroy but I am sure the Emperor will be pleased to hear that we are half-way to building the Death Star.
codyb
The on a log scale is doing a fair amount of lifting here I think
amelius
Next question: on what planet/moon should the mosquito be to be _just_ safe from the laser?
zahlman
Well, mass scales as the cube of radius, and we have 15 orders of magnitude to work with, so I guess it should be an object on the order of hundreds of meters in radius. But as noted, the duration of firing matters as well. Given https://news.ycombinator.com/item?id=44054239, the actual laser can only vaporize much smaller things.
jvanderbot
Thank you for this, I will be using this for the rest of my life!
dyauspitr
I don’t like log scales, they’re not intuitive.
otteromkram
> Optical devices called diffraction gratings stretch it out in time so that when the pump lasers dump power into the pulse, it doesn’t get so intense that it starts tearing the air apart.
Oh,my.
> "The crystal that we’re going to get in the summer will get us to 3 petawatts, and it took four and a half years to manufacture"
This entire thing is beyond cool. I hope the rest of the process goes smoothly for the teams involved!
hinkley
I was hoping I could hear it make noise but it operates for millionths of nanoseconds. Human ears have trouble with anything less than 30 ms so when it runs a trillion times longer we’ll be able to hear it make a sound.
mitthrowaway2
You can hear femtosecond lasers because they ionize the air, creating a spark. They buzz at the pulse repetition frequency.
hinkley
Do you know how often this one pulses? I was getting the impression it fires once per hour given the power levels.
FiatLuxDave
Big powerful lasers can actually be quite noisy. Once I was talking on the phone with a friend who was working on one of the big lasers (don't remember which one, but it was in the bay area) and he said,"What? What? I'm sorry I can't hear you over the sound of my laser!". When he could hear me, I told him that was one of the coolest things I'd ever heard anyone say.
chneu
It's usually the accessories and support equipment that makes lasers loud. Cooling equipment, electrical stuff, etc.
If those can be put in another room then the noise goes way down.
metalman
china is on track to have a 100pettawatt laser operating this year called "The Station of Extream Light", SEL for short, which is going to be used to try and seperate energy and matter by breaking empty space. think that this links to the place building it http://english.siom.cas.cn/Newsroom/rp/202207/t20220701_3071... all in all good to have a competitive environment in reseach.......though the US government, cough, cough, might, nudge, think about, some funding there
zahlman
> Extream
[sic]?
null
megous
I don't think anyone should be impressed by watts. Jouls are where all the real work is.
Asside for the PR article. What's the use case for pettawatt laser pulse lasting 25 quintillionths of a second?
hinkley
Laser pulses can ablate materials and the shorter the pulse the crisper the edges. Back in the 90’s or early 00’s they demonstrated pulses laser cutting of tissue where the heat damage to surrounding tissue had a width of a single cell.
ourmandave
What, like a surgical laser?
"Okay, hold really still..."
hinkley
Yeah and I think this and radiological tools are why chemo tattoos exist. The system has to react to the twitch you can’t control when a weird noise happens next to your head. Instead of stabbing bolts into your skull through your skin with a device Torquemada would have been proud of, they target versus the dots and if the dots move? Well this is where my knowledge runs out. Either they shut down the beam or they target in realtime. But either way the payload is delivered where it’s supposed to be or not at all.
I don’t know if they are using laser scalpels in surgery. My medical fascination mostly ends at diagonostics and experimental procedures. If I don’t know anyone with a disorder I tend not to hear about new procedures. My friend in college was helping a prof work on picosecond violet lasers and now we are on femtosecond.
mmastrac
At femtoseconds, assuming your tracking matches, you could probably sit a sugar-loaded kid in a chair without instructions and just make it work.
cnees
A previous press release lists some research applications and potential practical developments. https://news.engin.umich.edu/2019/09/most-powerful-laser-in-...
megous
Thanks. :)
frollogaston
Well you probably don't want a petawatt laser lasting a second, cause it'll obliterate a lot more than what you wanted to.
ta1243
Including of course the laser. It's about 240 kilotons of TNT, or over 10 times the power of the nagasaki or hiroshmia bombs.
frollogaston
Yeah, or even if it were some more reasonable amount of energy that doesn't self-destruct it, there are probably applications where you want to hit a small area quickly without burning things around it.
floxy
Seems like you always start somewhere. First you have 25E-18, then bump it up to 1e-15, and maybe someday you are at 1e-9 and are doing inertial confinement fusion.
EnPissant
Watts are just joules per second.
It doesn't make any sense to measure joules alone. _Any_ laser can output 2 petajoules. The only question is how long it takes to do that: hence Watts.
ourmandave
Mount it in a jet and you could pop an entire house full of popcorn in seconds.
amelius
Point it downwards and make that hole through the center of Earth.
hinkley
That’s popcorn. Get it away from me, I can’t stand popcorn. I hate popcorn.
loloquwowndueo
More for us, then!
MisterTea
It's an on topic movie quote: https://www.imdb.com/title/tt0089886/quotes/?item=qt0435723&...
cnees
In femtoseconds!
tonyhart7
star wars??? space wars???
I see a number of comments here misunderstanding the power of this laser. Laser facilities like this one are designed for incredibly short pulses that are femtoseconds long, and total energy per pulse is typically on the order of tens of joules, roughly equivalent to a few seconds of your phone flashlight. They can’t destroy much of anything on human scales. They are made to do physics research, and there is absolutely no pathway from a 2 petawatt laser that delivers a few joules a minute to a 2 petawatt laser that hits full output power for a few seconds: that would be 10^16 times more energy, and of course that brief pulse would use more electricity than all the US uses in a year and completely destroy the University of Michigan in spectacular fashion (very roughly equivalent to a five megaton nuclear explosion.)
If you’re interested in the most energy per pulse, you want the “most energetic” laser, which is the NIF at LLNL. That’s about 2 megajoules per pulse or half a kilowatt hour. Definitely enough to kill a mosquito, but it doesn’t even register on the scale of Death Star style lasers from fiction.
And if you want the most destructive power, those are all military lasers. Which can absolutely destroy things science fiction style, but on a fairly small scale and with some important limitations.