Implementation of a novel reflective doublet based stretcher design for a sub-50-fs chirped pulse amplification laser system

Abstract

Summary form only given. The design of pulse stretchers for chirped pulse amplification laser systems becomes more complicated as the pulse duration decreases. For durations below 50 fs, high-order phases (up to fifth and sixth order) become important due to the large associated bandwidth (e.g., 23 nm for a 30-fs sech/sup 2/ pulse centered at 800 nm). Optical components in the stretcher and compressor have to be large to accommodate this bandwidth; therefore off-axis aberrations must be minimised and imperfect surface figures must be taken into account. To facilitate this difficult design process and to compare existing stretcher designs, a full three-dimensional ray-tracing model has been developed. The model traces a bundle of beams representing a finite beam profile, each beam containing thousands of spectral component rays. The rays are traced from surface to surface using ray-transfer equations and, where appropriate, the grating equation.