An international team of researchers recently demonstrated an innovative technique to increase the intensity of lasers, opening the way to the study of a new type of physics.
Reduce pulse duration instead of increasing laser energy
In the context of work recently published in the journal Applied Physics Letters, an international team of researchers has demonstrated an innovative technique to increase the intensity of lasers. Based on the compression of light pulses, this approach would make it possible to reach a sufficient intensity threshold for a new type of physics that has never been explored before: the phenomena ofquantum electrodynamics.
Since the invention offrequency drift amplification in 1985, the power of lasers increased phenomenally and finally leveled off in recent years. Many research groups are remedying this situation by amplifying the energy of the laser to increase its power, but this expensive approach requires very wide beams and optics, more than a meter.
Researchers Jean-Claude Kieffer of the’National Institute for Scientific Research ((INRS), EA Khazanov of the’Institute of Applied Physics of the Russian Academy of Sciences and Gérard Mourou, professor emeritus of thePolytechnic school of Paris having received the Nobel Prize in Physics in 2018, chose a different direction to reach a power of around 10 ^ 23 Watts (W). Rather than increasing the energy of the laser, they reduce the duration of the pulse to a few femtoseconds only. This would limit the size of the device required and by extension the operating costs.
“If we get very short pulses, we get into relativistic problem classes”
In order to generate the shortest possible pulse, the researchers exploit the effects of nonlinear optics. ” A laser beam is sent through an extremely thin and perfectly homogeneous glass slide. The particular behavior of the wave inside this solid medium widens the spectrum and makes it possible to obtain a shorter pulse when it is recompressed at the exit of the blade. “, Explain Jean-Claude Kieffer, co-author of the study.
Installed in the Femtosecond sources laboratory ((ALLS) of the’INRS, the researchers limited themselves to an energy of 3 joules for a pulse of 10 femtoseconds, or 300 terawatts (1012W). They plan to repeat the experiment with an energy of 13 joules on 5 femtoseconds, an intensity of 3 petawatts (1015 W). ” We would be among the first in the world to reach this power level with a laser with such short pulses. “Explains the professor Kieffer.
” If we get very short pulses, we get into relativistic problem classes. It is an extremely interesting direction which could lead the scientific community towards new horizons “Continues Kieffer. ” It is a very beautiful work which consolidates the primordial potential of this technique “, Concludes Gérard Mourou.