An innovative amplifier developed by Polish scientists enables building 10 terawatt lasers that fit on a desk.
Unlike conventional amplifiers, the new invention does not rely on sapphire crystals doped with titanium ions, but takes advantage of the so called non-linear optical effects.
These parametric amplifiers transfer energy effectively and directly from the pumping laser beam to the beam being amplified. As the input energy is not stored anywhere, no adverse thermal effects occur, and the amplified pulses have excellent parameters.
“Theoretically, the efficiency of parametric amplifiers can reach over 50 per cent. In practice, the best amplifiers of this type are operated at an efficiency of about 30 per cent. We have reached this level already now, and what's more, in a really compact device”, said Yuriy Stepanenko, a researcher at the Laser Centre of the Institute of Physical Chemistry of the Polish Academy of Sciences and chief constructor of the amplifier.
“We are still improving our setup. In the coming months we are going to increase the amplifier's efficiency by another few per cent on one hand, while on the other, we intend to increase the power of the laser pulses up to a few tens of terawatts.”
Parametric amplifiers can amplify light by hundreds of millions of times on an optical path of a few centimetres. This quality enables the engineers to pack these lasers into a much smaller package than those utilising standard high power optics.
Comfortable fitting on a half of a desk, the device is capable of producing short laser pulses of the duration of several femtoseconds, generating power of 10 terawatts, which is more than the power of all world’s nuclear power plants.
The team believes they are on the right path to develop portable, low cost high power devices that could bring about a revolution in anti-cancer therapies. It has been tested as a source for an x-ray device, providing protons and secondary neutrons.
The goal is to develop a device capable to generate laser pulses with the power of 200 TW and more. Such powerful light pulses could be used for accelerating protons to energies required in medical therapies, for instance to selectively kill cancer cells.
The existing techniques for proton acceleration require construction of huge and high cost accelerators. The desktop-sized high power lasers would therefore allow for significant increase in availability of the state-of-the-art proton therapies, while at the same time considerably reducing cost for cancer patients.