Random Continuous Polarization Benefits for Inertial Confinement Fusion Facilities

Random continuous polarization (RCP) devices provide instantaneous polarization smoothing (PS) of far-field speckle with optional far-field spot-envelope control by means of random birefringent patterns, realizable in a variety of birefringent materials.[1] Inertial confinement fusion (ICF) facilities utilize PS devices to mitigate directly driven on-target speckle modulation. The designed RCP patterning smooths uniformly in all directions by minimizing both near- and far-field spatial correlations, in contrast to a traditional birefringent wedge, or regular birefringent patterns. The RCP achieves PS by creating two uncorrelated and orthogonal far-field speckle patterns that add through intensity. The RCP maintains far-field speckle-pattern envelope control by randomly sampling a distributed phase plate or by inducing its own near-field phase modulation. In addition, the RCP provides other unique advantages for directly driven ICF systems by mitigating spot-shape distortion, reducing the number of optics, and reducing the polarization-dependent, cross-beam energy transfer effect from displaced and overlapped beams. This talk explores the ICF advantages of the RCP devices designed and manufactured for the OMEGA Laser Facility and their application to other facilities. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856.

 

[1] J.-M. Di Nicola et al., U.S. Patent No. 20210239893 (08 May 2021).