Influence of grooves misaligned reflection grism stretcher on femtosecond pulse in chirped pulse amplification system

Abstract

The misalignment of the compressor or stretcher based on the grisms is unavoidable in a chirped pulse amplification laser system. In this paper, analytical expressions for the dispersion of misaligned grooves in reflection grism stretcher are presented. The residual dispersion in a chirped pulse amplification system due to the misaligned grism stretcher is analyzed. Furthermore, we evaluate the effects of the residual dispersion on the femtosecond pulse. Results show that when the grism grooves are misaligned, the rotation angle of grooves and incidence angle have great effects on the dispersion of grism pair, especially on the third-order dispersion. The rotation direction of grism grooves has no influence on the dispersions. Residual dispersions resulted from the misaligned grism stretcher have arisen in the CPA system. Therefore, the residual dispersions lead to an increase in the recompressed pulse duration. Meanwhile, the pulse waveform tilts backward and exhibits a severe wing on the trailing edge of the pulse.