Peking University successfully developed 200TW / 1Hz femtosecond laser system
Ultra-short and super-strong laser has great application value in laser acceleration, laser fusion, attosecond science, astrophysics, nuclear physics, high-energy physics, atomic and molecular physics, nuclear medicine and other fields, and is one of the frontiers of international laser science and technology competition. Most of the current, commercialized ultra-short and ultra-strong laser light sources and the corresponding pump laser systems worldwide are provided by Thales and Amplitude in France.
With the support of the key research and development plan of the Ministry of Science and Technology, Peking University is developing a proton radiotherapy system based on ultra-short and super-strong laser, and the stable and reliable repeated frequency ultra-short and super-strong laser is the core unit of the whole system. In order to avoid cutthroat problem, with the support of Beijing university and Guangdong emerging laser plasma technology institute, laser acceleration team backbone members in 2020 Zhao Yanying senior engineer led the tile laser front-200TW laser system development work, after two years of hard research, on August 4th,2022, they successfully completed 200TW laser system field test, peak power reached 214.8TW.
In order to meet the application needs of the laser proton radiotherapy system, the 200TW laser system takes the chirp pulse amplification technology (CPA) and the cross-polarization filtering technology (XPW) as the overall technical route. At the same time, the laser wavefront detection and control scheme is studied to ensure the spatial quality of the laser output spot. A laser system with an energy of 8.6J, an energy stability of 1.3%, a repetition frequency of 1Hz, a pulse width of 29.2fs, and a peak power of 214.8TW was finally obtained. While ensuring the advanced performance of laser parameters, a number of key auxiliary functions are added to the application needs: including return monitoring system, low heavy frequency laser self-collimation system, large energy and large size laser attenuation system, etc., which is a step forward for the realization of 200TW, laser system and PW laser system.
In the process of 200TW laser system development, research group and Shanghai optical machine, Changchun optical machine, zhuo laser laser and other domestic technical advantage unit cooperation, successfully implement the pump source, laser gain medium core device localization replacement, implements the 200TW / 1Hz high contrast laser system localization, effectively cope with the impact of environmental changes at home and abroad. The research group in the early stage also developed a 10TW femtosecond laser device for ENN company, which will be used for the two-dimensional magnetic field diagnosis research of fusion plasma core. The above research and development can significantly reduce the development cost of ultra-short and super-strong laser, which lays a solid foundation for the realization of commercial mass production PW laser system with independent intellectual property rights, stable reliability and high universality, and also lays an important foundation for the large-scale application of laser proton radiotherapy system.
