Design and fabricate large scale gold coated pulse compression grating for Ti: sapphire laser

摘要

Large scale and broadband pulse compression grating which is used in the femtosecond Ti: sapphire laser is studied. The line density of gold coated pulse compression grating is 1740lp/mm. The working wavelength of gold coated grating is from 700nm to 900nm and its deviation angle is 16.6 degree(@800nm). By using rigorous coupled wave theory, a series of calculation results with different profiles of gold coated pulse compression grating, such as rectangular, sinusoid, semi-sinusoid, are discussed in this paper. In order to get high diffraction efficiency throughout the whole working band, the duty cycle of grating should be more than 0.5 for the rectangular or semi-sinusoidal profile of groove. Duty cycle of grating causes the diffraction efficiency to change quickly at the short wavelength. By using holographic recording method, the gold coated pulse compression gratings with the aperture of 200mm × 400mm have been fabricated. The gratings exhibit -1st order diffraction efficiency in excess of 94%(TM@808nm).