Shanghai Optical Machinery Institute has made progress in high-efficiency optical parametric amplification technology

Recently, a joint research team composed of Sun Meizhi, associate researcher of the High Power Laser Physics Joint Laboratory of the Chinese Academy of Sciences Shanghai Institute of Optics and Precision Mechanics, and Tu Xiaoniu, associate researcher of the Chinese Academy of Sciences Shanghai Institute of Silicate, proposed a new configuration of cross Fabry Perot intracavity optical parametric amplification (XOPA), and completed the experimental demonstration based on the front platform of the SG - Ⅱ 5PW laser device. The related achievements are titled "Optical Parametric Amplification in Crossed Fabry Perot Cells" and published in Laser Photonics Reviews.

Optical parametric amplification (OPA) and chirped pulse optical parametric amplification (OPCPA) are important technological routes for rapidly developing high-power laser systems, and are also the mainstream technological routes for future tens to hundreds of watt laser systems. The development of this field has put forward comprehensive requirements for laser amplification technology in terms of efficiency, energy, bandwidth, gain, beam quality, signal-to-noise ratio, and shaping ability.

The research team placed nonlinear crystals in a cross Fabry Perot cavity, constrained signal light and pump light to achieve multi-pass transmission and energy conversion, phased elimination of idle light, suppression of mixing three wave energy backflow, and thus achieving monotonic extraction of signal light and pump light energy. In the experiment, the YCOB crystal provided by the Shanghai Institute of Ceramics was used to achieve an output capability of 56.28% conversion efficiency of pump light from signal light in the 800nm wavelength band and a spectral width of 120nm; In addition, researchers designed unequal cavity lengths for dual Fabry Perot cavities, achieving high contrast amplification and shaping of chirped pulse signal light. This study indicates that the XOPA configuration has the ability to shape in the time, space, and frequency domains under the premise of high conversion efficiency, and is generally suitable for non collinear optical parametric amplification processes in all bands and nonlinear crystals, which is of great significance for improving the comprehensive performance of high-power laser systems.

Relevant work has been supported by the key projects of international scientific and technological innovation cooperation between the Ministry of Science and Technology, the National Natural Science Foundation of China, the Shanghai Natural Science Foundation, the Class A project of the Chinese Academy of Sciences strategic leading science and technology project and the Shanghai Sailing Plan project.

Figure 1 Schematic diagram of XOPA configuration

Figure 2: (a) Spectral evolution and (b) Theoretical simulation and experimental results of the 7-pass amplification process of XOPA

Source: Shanghai Institute of Optics and Precision Machinery