Suppression of transverse stimulated Raman scattering in large-aperture potassium dihydrogen phosphate crystals by pulse stacking

Effective suppression of transverse stimulated Raman scattering (TSRS) in a large-aperture potassium dihydrogen phosphate (KDP) crystal is an important scientific and technical problem in high-intensity laser research and applications. In this work, a method to suppress TSRS using pulse stacking is proposed. The method suppresses TSRS significantly, with greater numbers of subpulses producing more obvious suppression effects, and the threshold intensity growth rate of the 3 laser in the KDP crystal reaches up to about 1.9 when the stacked pulse contains four subpulses. This suppression effect is attributed to the fact that the polarization directions of adjacent subpulses are perpendicular to each other. The method can be used to suppress other nonlinear effects, including transverse stimulated Brillouin scattering in large-aperture optical devices and stimulated rotational Raman scattering in long air paths.