New progress in the study of broad spectral damage mechanism of low-dispersion mirrors at Shanghai Institute of Optical Machinery
Recently, the Department of High Power Laser Component Technology and Engineering of Shanghai Institute of Optics and Precision Machinery (SIPM), Chinese Academy of Sciences (CAS), has made new progress in the study of the broad-spectrum damage mechanism of low-dispersion mirrors. The research results were published in the journal "Ultra-broad-spectrum laser-pulse damage of low-dispersion mirrors The research results have been published in Optical Materials under the title of "Ultra-broad-spectrum laser-pulse damage of low-dispersion mirrors".
The optical parametric chirped pulse amplification technology is considered to be the most promising solution for realizing ultra-intense ultrashort lasers of 100 bW or even AIW, and low-dispersion mirrors are the key components of the ultra-intense ultrashort laser system for direction control and energy transmission, however, there are few reports on the damage studies of low-dispersion mirrors under the action of 200 nm lasers of the broad spectrum, and the mechanism of the damage is still unclear, which has restricted the enhancement of the performance of the damage of the low-dispersion mirrors of the broad-band laser.
Based on the front-end optical parametric chirped pulse amplification system of Shanghai Extreme Light Device, the research team has built a 200nm wide-spectrum nanosecond and femtosecond damage test platform, and systematically verified the damage characteristics of broadband low-dispersion mirrors under the action of wide-spectrum nanosecond and femtosecond pulsed lasers. Due to the existence of spatio-temporal chirp, the broad-spectrum nanosecond damage exhibits a high degree of determinism; it is examined that the protective effect of conventional protective layer technology is limited to the center band, while the edge component of the reflective band induces electric field enhancement, and the ability of the protective layer to raise the threshold depends on the competitive relationship between the two roles of the electric field protection and the electric field enhancement; in addition, it is found that the thermodynamic matching between the membrane layer materials is the key for the further raising of the threshold. For the femtosecond pulse damage in broad spectrum, a comprehensive electric field expression containing spectral width information is constructed to obtain the damage characteristics of ultrafast laser thin film under different spectral bandwidths, and the corresponding relationship between spectral bandwidth and the damage threshold of the thin film is established, which provides theoretical support for the enhancement of the damage performance of the broad-band low-dispersion mirrors. The study of broad spectral damage mechanism will provide theoretical support for the enhancement of broadband low-dispersion mirror damage performance, and lay the foundation for further improving the damage threshold of broadband low-dispersion mirror.
The related work was supported by the Key Project of International Science and Technology Innovation Cooperation between Chinese and Italian Governments, the National Natural Science Foundation of China, the Youth Innovation Promotion Association of the Chinese Academy of Sciences, and the Postdoctoral Science Foundation. (Contributed by High Power Laser Components Technology and Engineering Department)?
Shanghai Institute of Optics and Mechanics (SIOM) has made new progress in the study of broad spectrum damage mechanism of low dispersion mirrors.
Figure 1 Schematic diagram of broad spectrum damage test platform
Fig. 2 Damage morphology of broadband dispersive mirror
