Researchers at the University of Strathclyde in the United Kingdom have successfully developed the world's highest gain high-power laser amplifier. They use the laser system of the central laser equipment to conduct experiments, and the Vulcan device can output 150 J pulses. In both experiments, the researchers worked closely with CLF staff to adjust Vulcan so that two laser pointer beams of different colors could exchange energy in the plasma. The gain coefficient measured in the experiment was 180cm-1. 100 times the amplifier of the current high-power laser system based on solid media. Related research results were published in the journal.
The professor of the Department of Physics at Strathclyde University led the study. He pointed out: Raman amplification in plasma is a very attractive concept. This concept combines the views of Nobel Prize winner CV Raman Plasma, optics and laser physics are well combined. A relatively long high-energy laser pulse collides with a short, very low-energy pulse in the plasma. A shock wave will be generated at the collision place, just as the two water waves collide.
The light pressure of the shock wave will drive the plasma to form a regular or trapezoidal shape, and the multi-layered trapezoidal graph acts as a high-reflectivity, time-varying lens that reflects the energy of the high-energy pulse into the low-energy pulse, thereby amplifying the low-energy pulse and It is compressed into a green laser pointer ultra-short time light pulse. "Our experimental results are very important because these results prove the flexibility of the plasma medium as an extremely high-gain amplifier medium. The experimental results also show that the efficiency of the amplifier can be very large, at least to 10%, which is unprecedented, and There is a great possibility of improvement.
Of course, the current experimental results also show that it is still necessary to further study it in order to achieve a single-stage high-gain high-efficiency amplifier module. "For example, one of the challenges we still face is how to deal with the amplification of" noise "generated by random plasma fluctuations. This phenomenon will be exacerbated due to the extremely high gain. This will cause energy loss. Related research is ongoing, I believe that these problems can be solved well in the next experiment. "
The doctor who led the research team pointed out: Plasma is a completely decomposed medium, so it has no damage threshold, so it can amplify short red laser pointer pulses without compression after pulse broadening. Another advantage is that it is theoretically possible to achieve further compression during amplification, which may pave the way for the development of the next generation laser system. The new generation laser system will be able to output ultra-strong and ultra-short pulses, but the cost is only current. There is a small part of the laser. "However, we are not completely sure that this scheme relies on the control of Raman instability, its growth factor is very large, and small plasma fluctuations can cause large instability,