Influence of spectrum transmissivity of grating-pair in stretcher and compressor on output pulse temporal properties

Analytic expressions of spectrum transmissivity for the parallel grating-pair is deduced, with which the influence of the stretcher and compressor on the temporal properties of the output pulse laser can be analyzed. The analysis results show that, the spectrum transmissivity depends not only on the size and groove density of the gratings, but also on the size of the incident beam, the incident angle and the distance between the gratings. In a short pulse laser system, the stretcher has a much smaller cut-off bandpass than the compressor, which will limit the enhancement of the temporal contrast of the output pulse.