Smaller, cheaper, 300 times more intense: Scientists prove theory which could revolutionise lasers

Oct 11, 2010 by Lucy Stone
Optics being aligned on a laser system at the CLF
Optics being aligned on a laser system at the CLF

(PhysOrg.com) -- More brilliant X-rays, more cost-effective methods for developing new energy sources and advanced manufacturing processes are just some of the benefits which may come from a novel technology, proven at the theoretical level by a consortium of British and European laser scientists.

The research, led by scientists at STFC's Central Facility (CLF), is published in this week’s edition of Nature Physics (October 10 2010).

A team of scientists from the Instituto Superior Tecnico in Lisbon, Imperial College London, and the Universities of St Andrews, Lancaster and Strathclyde as well as STFC’s Central Laser Facility staff have demonstrated the feasibility of a groundbreaking method called Raman amplification which can take long laser pulses and compress them to 1000 times shorter, but with intensities 300 times greater.

This means that current very expensive and complex laser set-ups could eventually be replaced with smaller and more cost-effective systems. This would make many technologies, including methods used to develop which rely on lasers, far more accessible and easier to mass-produce. This latest development is another step in laser scientists’ quest to develop ever more powerful lasers, increasingly demanded by new technologies since the invention of the laser 50 years ago.

The technique has been examined over a two year period, using some of the world’s most powerful supercomputers, to test every possible aspect of the theory. "In the past, studies have been carried out to test the theory, but only using simplified models which do not include all of the relevant phenomena. Our new model has shown that, in most cases, the amplified laser beam breaks up into ‘spikes’, making it difficult to focus the beam to a small spot" said Dr Raoul Trines from STFC’s Central Laser Facility. "But for a few special cases, the amplified laser pulse is of excellent quality, enabling exceptionally tight focusing of the beam".

Professor John Collier, Director, STFC’s Central Laser Facility said: "This year’s celebration of 50 years of the laser is a poignant reminder that we need to start thinking about the next generation of laser technology. We have come to rely on lasers so much in our daily lives, for everything from high speed internet connections to medical techniques, that we can’t afford to pause even for a moment in developing laser techniques further, because these new techniques take years to develop and test".

The next step is to apply the theoretical study on an actual high power laser and fine tune the method through rigorous experimental testing.

Explore further: The first direct-diode laser bright enough to cut and weld metal

Related Stories

Recommended for you

'Comb on a chip' powers new atomic clock design

Jul 22, 2014

Researchers from the National Institute of Standards and Technology (NIST) and California Institute of Technology (Caltech) have demonstrated a new design for an atomic clock that is based on a chip-scale ...

Creating optical cables out of thin air

Jul 22, 2014

Imagine being able to instantaneously run an optical cable or fiber to any point on earth, or even into space. That's what Howard Milchberg, professor of physics and electrical and computer engineering at ...

New material puts a twist in light

Jul 18, 2014

Scientists at The Australian National University (ANU) have uncovered the secret to twisting light at will. It is the latest step in the development of photonics, the faster, more compact and less carbon-hungry ...

User comments : 20

Adjust slider to filter visible comments by rank

Display comments: newest first

kevinrtrs
2.1 / 5 (13) Oct 11, 2010
In case you missed it, this could mean the ray-gun is just around the corner....
The military will absolutely love it. So would the robbers, hijackers, drug smugglers and the like.

Of course, it's not ALL bad. Medicine, communications, video, storage devices etc. will all also benefit.
Trim
5 / 5 (11) Oct 11, 2010
It should help in developing nuclear fusion.
Husky
not rated yet Oct 11, 2010
in what way is raman amp different from chirping?
Yellowdart
4.9 / 5 (10) Oct 11, 2010
Sure Kevin, but the bad guys will have red lasers and the good guys will have blue lasers...and knowing is half the battle :)
PinkElephant
4.6 / 5 (11) Oct 11, 2010
@kevinrtrs,
this could mean the ray-gun is just around the corner
Regardless of how you compress a beam, you can't create more energy than there was originally in the beam. More power delivered, but over a shorter period == same overall amount of power (even before considering the thermodynamical losses inevitably suffered by any energy-processing mechanism.)

The fundamental obstacle to "ray guns" is not the emitter, but the power cell. It remains energetically far more efficient to just lob an explosive at the enemy, rather than trying to convert chemical (never mind nuclear) energy into light, so as to deliver the light onto the target. Lasers are advantageous only when you need to hit a small, fast-moving target from far away, or when you want to avoid making too much noise. But you pay the price by having to haul gigantic power plants and fuel reserves to feed the beam.
Simonsez
4.5 / 5 (13) Oct 11, 2010
But you pay the price by having to haul gigantic power plants and fuel reserves to feed the beam.


TODAY we have to haul gigantic power plants etc. I find it amusing how short-sighted some commenters on this site can be about the rate of progression (and more pertinently, micronization) of technology. You might consider reading up on Ray Kurzweil's predictions.

50 years ago, people scoffed at the idea you could have a computer that wasn't as big as a house. Now people carry them in the palm of their hand. Claiming that "ray guns" and such are "just around the corner" is not far off the mark, depending on how you subjectively interpret the distance in time to round said corner.
altino
not rated yet Oct 11, 2010
GO Técnico. :)
jjoensuu
not rated yet Oct 12, 2010
hmmm...

I guess they could then combine the use of this Raman Amplification with these "nano antennas" that can also amplify the laser intensity, as explained here:
Nano antenna concentrates light
http://www.physor...457.html

And finally put all these together for regular visible in this new projector:

Researchers develop tiny projector
http://www.physor...130.html

This way people like myself who need to do presentations can get sufficient light intensity from tiny projectors. And no longer have to carry a large projector with them everywhere.
otto1932
not rated yet Oct 12, 2010
@Pinkel
Lasers are advantageous only when you need to hit a small, fast-moving target from far away, or when you want to avoid making too much noise.
You are guessing sir. Comment without research- not good for cred:
http://www.youtub...a_player
-These are in the works.
PinkElephant
4 / 5 (1) Oct 12, 2010
@otto,

Notice that they don't show you what's behind the beam (i.e. the generator/capacitor/batteries/whatever that's powering the laser.) It would've been just as effective to shoot a high-velocity bullet into those IEDs. And it would've been a lot more of a compact, weight- and volume-efficient, and energy-efficient approach...

Which is pretty much the point I was making.
Pyle
5 / 5 (2) Oct 12, 2010
Have your buddy hold out his palm. Push your arm against it as hard as you can. Now have him hold out a pen instead. Care to push as hard?

300 times more intense = ray gun, or something close to it. Isn't this what the sun through a magnifying glass is? Focusing small amounts of energy into very small areas can cause significant damage.
PinkElephant
3.7 / 5 (3) Oct 12, 2010
@Pyle,

They aren't talking about reducing the laser beam's cross-section. They're talking about taking a long pulse and compressing it. 1000 times shorter, but only 300 times more intense (70% energy loss!) Yes, it impacts with more instantaneous force. So it would be more effective at rapidly heating and turning into plasma the top few atoms of the target's surface. However, the ultra-short duration of the pulse means those atoms will likely have cooled down and re-joined the target's surface, before the next pulse arrives.

More useful might be the extreme (but still extremely transient) electric and magnetic fields carried by such ultra-short pulses. They might allow more precise and subtle manipulation of nanoparticles and molecules. Or, the shorter/more intense pulses may aid long-distance communication through fiber optics -- increasing both maximum distance, and bandwidth at the same time.
Pyle
5 / 5 (2) Oct 12, 2010
@Pinkel
Same difference. Put ten pounds of pressure on a table for 20 minutes. Now put 3,000 pounds on it for one second.

Granted, my focusing using a lens and palm vs. pen examples did give the impression of "reducing the laser beam's cross-section". That wasn't my intent; merely convenient, albeit misleading, comparisons.

Ultimately the efficacy of the laser on materials will depend on their ability to cool down and re-join, but I think you are underrating the power of the ray gun!
otto1932
5 / 5 (1) Oct 13, 2010
@otto,

Notice that they don't show you what's behind the beam (i.e. the generator/capacitor/batteries/whatever that's powering the laser.) It would've been just as effective to shoot a high-velocity bullet into those IEDs. And it would've been a lot more of a compact, weight- and volume-efficient, and energy-efficient approach...

Which is pretty much the point I was making.
Again I am dismayed at your reticence in research-doing:
http://en.wikiped..._Avenger
-Theyre putting this on humvees.
http://www.popsci...oduction
-Still not very big at all.
It would've been just as effective to shoot a high-velocity bullet into those IEDs.
Again youre guessing? The armys paying $$ for these anti-IED lasers- they must feel they would be useful? Pinkel?
Which is pretty much the point I was making.
Without actually looking it up. Twice.
PinkElephant
1 / 5 (1) Oct 13, 2010
@otto,
Still not very big at all
Did you notice it needed to be mounted on a TRUCK? You know, high-velocity bullets only require a rifle, which can be CARRIED by a single person.
The armys paying $$ for these anti-IED lasers
Oh, I bet they're paying all kinds of $$$ for all kinds of crap. There has never been a more wasteful branch of government, than the Pentagon. It's really not so much of a military administrative complex, as it is a military-industrial corporate welfare agency.
PinkElephant
not rated yet Oct 13, 2010
@Pyle,

I take your point. However, it still all comes down to the power pack.

If you can only carry around 100 kJ worth of energy in a small/portable package, then that's all the energy available to you. You can try to dump all of that energy onto a target over a very short time span, but the end result is still you're only delivering 100 kJ. The shorter the time interval, the sharper the 'punch', but unless you bring enough energy overall, this sort of thing is only useful for peeling paint or burning retinas.

So for instance, the NIF lasers are able to deliver power on the scale of the entire energy generation of the United States in one pulse. Trouble is, they can only deliver that power over the span of the order of 1 femtosecond. Certainly enough to vaporize a tiny little metal capsule. But probably not quite enough to even punch through body armor, never mind HMMV or something thicker.
that_guy
not rated yet Oct 16, 2010
@Pink. They blow up IEDs with explosives or guns. with some research, a laser, which does not need ammunition, could be more efficient in the long run.

The military likes lasers because you can do some things easier that are incredibly difficult to do with a bullet that is affected by wind, gravity, and time.

A laser can target and hit an object, such as a missile, more readily than a bullet can. The AMS systems on ships are changing to lasers because they are better suited to the task than machine guns are.

laser intensity is key to many types of uses, including weapons, especially once you hit the vaporization point of a material. if the laser just 'melts the armor' then it will waste a lot of energy as it keeps heating the melting material as it cools. If it 'vaporizes the armor', then it can continue to cut through, as the vaporized material will essentially puff out of the way. Guess which method will be an order of magnitude more efficient for a given amount of enrg
robbor
not rated yet Oct 17, 2010
when the time comes, instead of cremation i could be lased and POOF! - my body is gone.
Quantum_Conundrum
not rated yet Oct 19, 2010
Pink Elephant:

The High Energy Lasers are able to shoot down RPGs, mortars, and UAVs, and other small missles and aircraft, and potentially damage or destroy enemy ground vehicles by destroying the fuel tank or explosive cargo. They are not just for destroying IEDs from a safe distance.

These trucks would serve much the same role on ground as our destroyers serve on water, (and by the way, the Destroyers and aircraft carriers are going to have THEL lasers on them soon too, if they don't already...) The trucks will provide anti-air support for advancing tank and infantry units, to protect against UAV, small missiles and mortars that conventional anti-air units cannot really counter.

One day, stronger versions of these lasers will probably be used to detonate conventional ballistic artillery rounds in flight, before they hit their targets.
tech0100
not rated yet Oct 19, 2010
@pink
"They're talking about taking a long pulse and compressing it. 1000 times shorter, but only 300 times more intense (70% energy loss!)"-pinkelephant

Given that this is more just a proof of concept you can't really say, based on these results, that the system is to inefficient to be feasible or that it's going to require a massive power supply. The reality of the situation seems to be that this technology would allow for a smaller power supply for the laser itself since (based on these early numbers) the output would have to be 300x less intense to produce a short duration of the output a 300x more intense unit would be able to produce constantly.

so for ray-guns you'd get away with a smaller, less energy demanding unit (depending on the demand/size of the Raman amplifier) meaning a hand held ray-gun with a charging time between each shot isn't that far fetched. Less star-trek and more Futurama "War Is the H-Word" episode though.
Zapp Brannigan: Stop exploding, you cowards!