Development of Broadband Pulse-width Compressed Gratings in China Has Made Important Progress

The key laboratory of the Chinese Academy of Sciences for high-power laser materials has made important progress in the development of a wide-bandwidth pulsed grating with a central wavelength of 800 nm. The research group adopts a global optimization design method combining simulated annealing and Fourier mode to design a wide-media pulse width compression grating (PCG) with 800nm ​​center wavelength (see: Optical Letters, 35 (2010) 187). .

The members of the research group obtained a full dielectric film with a threshold value of ~1 J/cm2 (50 fs, TE, and 57° incidence) after extensive optimization and tolerance calculations, combined with excellent film-making techniques, and the relevant grating parameters have large process tolerances. . The research team of China University of Science and Technology Synchrotron Radiation Optics Laboratory and the Diffraction Grating of Tsinghua University carried out the grating verification of the entire dielectric film provided by the research group and obtained a PCG sample with a bandwidth better than 110 nm. The research team tested the sample 0-order reflectance spectrum, and used a method of calculating the complementarity of the -1 and 0-order reflectances to obtain a bandwidth above 110 nm where the -1 order diffraction efficiency was greater than 95%, and the bandwidth was obtained for the first time in the international arena. 100 nanometers above all medium PCG samples.

All-media film PCG has the advantages of high diffraction efficiency and high damage threshold compared with currently used gold film gratings. It has important application prospects in high-energy femtosecond lasers with 800 nm. This study was supported by the National High Technology 863 Program and the National Natural Science Foundation.