Spatially random polarization-smoothing optics by residual stress birefringence of fused silica for laser-driven inertial confinement fusion

We demonstrate a new polarization smoothing (PS) approach utilizing residual stress birefringence in fused silica to create a spatially random polarization control plate (SRPCP), thereby improving target illumination uniformity in inertial confinement fusion (ICF) laser systems. The fundamental operating mechanism and key fabrication techniques for the SRPCP are systematically developed and experimentally validated. The SRPCP converts a linearly polarized 3ω incident laser beam into an output beam with a spatially randomized polarization distribution. When combined with a continuous phase plate, the SRPCP effectively suppresses high-intensity speckles at all spatial frequencies in the focal spot. The proposed PS technique is specifically designed for high-fluence large-aperture laser systems, enabling novel polarization control regimes in laser-driven ICF.