Reducing parametric backscattering by polarization rotation
Abstract
When a laser passes through underdense plasmas, Raman and Brillouin Backscattering can reflect a substantial portion of the incident laser energy. This is a major loss mechanism, for example, in employing lasers in inertial confinement fusion. However, by slow rotation of the incident linear polarization, the overall reflectivity can be reduced significantly. Particle in cell simulations show that, for parameters similar to those of indirect drive fusion experiments, polarization rotation reduces the reflectivity by a factor of 5. A general, fluid-model based analytical estimation for the reflectivity reduction agrees with simulations. However, in identifying the source of the backscatter reduction, it is difficult to disentangle the rotating polarization from the frequency separation based approach used to engineer the beam's polarization. Although the backscatter reduction arises similarly to other approaches that employ frequency separation, in the case here, the intensity remains constant in time.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 01, 2016
- Source ID
- 10.1063/1.4964291
Entities
People
- Ido Barth
- Nathaniel Fisch
Organizations
- Air Force Office of Scientific Research
- Princeton University
- United States Department of Energy