Simulations of a phase corrector plate for the National Ignition Facility

Simulations are presented on the effect of placing a static phase corrector plate in each beamline of the National Ignition Facility (NIF) to assist the adaptive optic in correcting beam phase aberrations. Results indicate such a plate could significantly improve the focal spot, reducing a 3{omega}, 80% spot half-angle from 21 to 8 {micro}rad for poorer-qualtiy optics, and 17 to 7 for better optics. Such a plate appears to be within the range of current fabrication technologies. It would have an alignment requiremnt of {+-}0.5 mm, if placed in the front end. In NIF operation, the occasional replacement of laser slabs would slowly degrade the beam quality for a fixed corrector plate, with the spot size increasing from 8 to 15 {micro}rad after four new slabs for poorer optics, and 7 to 12 {micro}rad for better optics. The energy fraciton clipped on the injection pinhole ({+-}100 {micro}rad) would be