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 research of positive and negative 1000 fs2 high dispersion mirror pairs. The research results are entitled "Design, production, and characterization of a pair of positive and negative high dispersive mirrors for chirped pulse amplification systems". Design, production, and characterization of a pair of positive and negative high dispersive mirrors for chirped pulse amplification systems" was published in Optics Express.
High dispersive mirrors have been used as extracavity pulse compression elements in chirped pulse amplification systems due to their high reflection, high dispersion, and high dispersion compensation accuracy. High dispersion mirrors with higher dispersion compensation and wider bandwidth can support pulse output with narrower pulse width and higher energy, which can help improve the output quality of ultrafast laser systems. At present, the research on high dispersion mirrors mainly focuses on negative dispersion mirrors, positive dispersion mirrors are seldom reported, and positive and negative high dispersion mirrors can be used as pulse broadening and compression elements in chirped pulse amplification systems, respectively.
Fig. 1 Simulation of pulse broadening and compression with positive and negative 1000 fs2 high dispersion mirrors.
The research team proposed an initial structure of high dispersion mirror for MGTI (Modified Gires-Tournois interferometer) mirrors, i.e., by replacing part of the reflective film layer of the standard GTI mirror by two periodic symmetric film systems, so that the G-T cavities and the symmetric cavities composed of the symmetric film systems form a tandem form, and then the design obtains the positive and negative high dispersion mirrors of +1000 fs2 and -1000 fs2@750-850-800 fs2, respectively. 1000fs2@750-850nm high dispersion mirrors. The high dispersive mirrors are successfully prepared by using dual-ion beam sputtering technology, and their performance tests are completed by combining spectrophotometer and white light interferometer to successfully verify the preparation accuracy of high dispersive mirrors. Using pulse simulation, the pairing effect of positive and negative high dispersion mirrors was verified. A study on the damage of positive and negative high dispersive mirrors under the action of femtosecond laser has also been carried out, explaining the formation and development of high dispersive mirror bulge under the action of femtosecond. The positive and negative 1000 fs2 high dispersion mirrors will be expected to be applied to the chirped pulse amplification system as amplification and compression stages, respectively, to realize the chirped pulse amplification system based on the amplification and compression of high dispersion mirrors.
Fig. 2 - 1000fs2 high dispersion mirror bulge morphology
