Design of femtosecond pulse stretcher

A kind of compact and effective femtosecond pulse stretcher was designed based on the Kirchhoff-Fresnel integral where the pulse passed grating 4 times. Not only a high stretching rate of 300 for stretching a pulse width of 100 fs when the grating is 1200 1/mm has been obtained, but also the spatial characteristics of the light beam through the stretch has been reconstructed. If a larger stretching rate is required, gold coated holographic grating of 1800 1/mm, even 2400 1/mm, has to be selected.