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 3ω 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.

Transverse stimulated Raman scattering (TSRS) is strongly generated in the third-harmonic-generation crystal potassium dihydrogen phosphate (KDP) and can even damage the KDP crystal in inertial confinement fusion drivers. In this work, a method to suppress TSRS is proposed in which the polarization control plate (PCP) is moved to a new position in the existing optical path. The proposed method can suppress TSRS significantly and doubles the laser threshold intensity in KDP crystal when the order of the PCP is 16. This result is attributed to the reduction of the gain length for the Stokes radiation. The proposed method may also be used to suppress other nonlinear effects, including transverse stimulated Brillouin scattering in large-aperture optical components.