Laser pulse pattern influenced by mosaic grating gap

High energy efficiency and well-distributed output on the surface of the chirped pulse grating are required in the laser pulse compressor with mosaic gratings as the dispersion element. Fresnel-Kirchhoffs diffraction theory is utilized to study the light distribution on the grating surface and the far-field diffraction pattern. The variations of the light intensity on the grating surface and the maximum value of the far-field light intensity influenced by the mosaic grating gap are calculated. It is found that the light distribution is related to the width of the gap for light incidence near the Littrow angle, and the width of the gap should be limited within 0.5 mm. When the diffraction efficiency of the gap increases, the light distribution will be more uniform and the output ener