The art of amplification: A desktop-size 10 terawatt laser

Oct 03, 2013
The art of amplification: a desktop-size 10 terawatt laser
New parametric amplifier developed in the Laser Centre at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw and the Faculty of Physics of the Warsaw University allows for constructing desktop-size laser setups capable of generating femtosecond laser pulses with a power of tens of terawatts. Pictured above: Dr Paweł Wnuk from the Laser Centre at the new amplifier. Credit: IPC PAS, Grzegorz Krzyżewski

A compact new generation optical amplifier has been constructed by physicists from the Laser Centre of the Institute of Physical Chemistry of the Polish Academy of Sciences and the Faculty of Physics of the Warsaw University. The apparatus is extremely efficient and small enough to fit on a desktop and is able to generate over 10 terawatt light pulses.

Can a device with a footprint not larger than half of a desktop produce power a few dozen times higher than that generated by all worldwide? The answer is: "yes – in a pulse"! A new parametric amplifier constructed in the Laser Centre at the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) and the Faculty of Physics of the Warsaw University (FUW) allows to produce very short (femtosecond) pulses with a giant power of 10 terawatt. The new amplifier represents an important step towards construction of compact, portable, relatively low cost high power laser devices that could revolutionize, e.g., anti-cancer therapies.

"Theoretically, the efficiency of parametric amplifiers can reach over 50%. In practice, the best amplifiers of this type are operated at an efficiency of about 30%. We have reached this level already now, and what's more, in a really compact device", says Dr Yuriy Stepanenko (IPC PAS), the chief constructor of the amplifier, adding: "We still improve our setup. In the coming months we are going to increase the amplifier's efficiency by another a few per cent on one hand, while on the other we intend to increase the power of laser pulses up to a few tens of terawatts".

Most lasers generating ultrashort pulses amplify light using sapphire crystals doped with titanium ions. An external laser is used to pump energy into the crystal, and a fraction of the energy is subsequently taken over by a laser beam being amplified. The method has numerous disadvantages. One of the major ones is that the crystals warm up strongly leading to adverse distortions of the cross section of the laser beam. As a result, the crystals must cool down virtually after each laser shot.

Luckily, non-linear optical effects can be used to construct amplifiers of a different type. These parametric amplifiers transfer effectively energy directly from the pumping laser beam to the beam being amplified. As the input energy is not stored anywhere, there are no adverse thermal effects, and the amplified pulses have excellent parameters. Parametric amplifiers can amplify light by hundreds of millions of times on an optical path of a few centimeters only. That's also why they are really small in size, especially as compared with the standards of high power optics. The instrument from the Laser Centre of the IPC PAS and the FUW comfortably fits half of a typical desktop.

The new amplifier will be used for construction of an x-ray source and to generate experimentally protons and secondary neutrons.

One of the long-term objectives of the research on parametric amplifiers is to generate laser pulses with power of 200 TW and higher. Such powerful light pulses could be used for accelerating protons to energies that are useful in medical therapies, for instance to selectively kill cancer cells. The existing techniques for proton acceleration require construction of huge and high cost accelerators. High power lasers would allow for significant increase in availability of the state-of-the-art proton therapies, with simultaneous radical reduction of treatment costs for cancer patients.

The research on the parametric amplifier is financed by the National Centre for Research and Development (Project NR02001910).

The multi-pass optical parametric amplifier NOPCPA (Noncollinear Optical Parametric Chirped Pulse Amplifier) technology has been since 2005 developed in the Laser Centre of the IPC PAS and the FUW in a team headed by Prof. Czes?aw Radzewicz.

Explore further: Researchers get better metrics on laser potential of key material

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User comments : 9

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Moebius
1 / 5 (9) Oct 03, 2013
Sounds like a powerful hand held weapon is possible if we ever come up with a compact power source for it.
antialias_physorg
1 / 5 (1) Oct 03, 2013
Sounds like a powerful hand held weapon

At 0.01 Joule per shot..not really. At 200TW we're still in the 0.2J per shot range.
For comparison: The energy of a bullet is somewhere between several hundred to several thousand joules.
jalmy
1.4 / 5 (11) Oct 03, 2013
But how much energy do you need to say burn a pin hole through a heart? In terms of pure killing power most of a bullets energy is really wasted. I bet a hand held device with the energy output discussed is quite capable. And would have the side bonus of being untraceable, Mount it to a small drone with tracking/targeting capabilities and you would have a hell of a thing.

"Sounds like a powerful hand held weapon is possible if we ever come up with a compact power source for it."

It's called a capacitor. You would only get 1 shot say per minute per se. But I imagine for most applications of small hand held weapons. One shot is enough.
Eikka
1 / 5 (3) Oct 03, 2013
But how much energy do you need to say burn a pin hole through a heart?


Not much, but that pinhole would seal itself in a matter of seconds without disturbing the working of the heart much.

The stopping power of a bullet is based more on its hydrostatic shock that travels through tissue and causes widespread damage, rather than the hole it makes. For example, a hit to the chest from an energetic bullet can cause blood vessels in the brain to burst, and it generally turns any nearby organ into minced meant.
packrat
1 / 5 (10) Oct 03, 2013
@Moebius,
Handheld laser rifles and pistols that would be effective can be built by anyone now. I've had plans for one posted for over 5 years on my personal website in the experimental firearms section. Your right, It's the battery pack that is the holdup on them being made and sold. Not the actual laser. The laser parts are pretty easy to get as they are sold commercially already and have been for years.
antialias_physorg
1 / 5 (1) Oct 04, 2013
You can have an effective laser 'weapon' at much lower cost and with next to no battery pack.
Equip the weapon with a camera and a low power scan mode. Scan the target area for characteristic reflections (eyes) by sweeping the beam via a DLP (the stuff that is in projectors. very small and can sweep an area hundreds of times per second). Up the wattage for one shot and burn retinas when it detected.
You don't even need to aim it.

A personal laser for 'punching holes in people' by shere burn is just too easily defeated. Protective clothing against lasers is much lighter/less expensive than that against projectiles.
packrat
1 / 5 (9) Oct 04, 2013
I will agree with you up to a point. But use a 30watt or higher with a fairly high speed pulse frequency and having reflective clothing wouldn't be much of a help for very long. It wouldn't have a very long range but it would definitely get peoples attention that are fairly close... say 50-100 yards or so.
TheGhostofOtto1923
1 / 5 (4) Oct 04, 2013
It's called a capacitor. You would only get 1 shot say per minute per se. But I imagine for most applications of small hand held weapons. One shot is enough
So you load a mag of supercapacitors. Or better yet, belt-fed SCs. The power source (the cartridge) is loaded this way in conventional firearms.
Not much, but that pinhole would seal itself in a matter of seconds without disturbing the working of the heart much
Headshot. Excellent sniper rifle.
Protective clothing against lasers is much lighter/less expensive than that against projectiles
Then why is the navy shooting missiles and planes down with them?
You don't even need to aim it
Nice idea for a remote turret.

Ive been watching the latest video game trailers and gameplay. The advances in detail and content just within the last year or so are breathtaking.
http://www.youtub...fdki5k1s
http://www.youtub...7vZuYzoA
http://www.youtub...KcOK8gno
TheGhostofOtto1923
1 / 5 (4) Oct 04, 2013
Or you have a bank of SCs in a backpack with a wire to your sidearm. The bank can charge at its leisure and can discharge in sequence at various speeds.

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