Using Polarization Control Plate to Suppress Transverse Stimulated Raman Scattering in Large-Aperture KDP Crystal

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.