Grazing-Incidence Metal Mirrors for Laser-IFE

The final optic in a laser-IFE power plant beamline experiences direct line-of-sight exposure to target emissions, including neutrons, x-rays, high-energy ions and debris. It must withstand this environment reliably over many months of continuous operation, while simultaneously meeting stringent optical requirements. A grazing-incidence metal mirror has been considered as a potentially robust design option that can survive acceptably high laser fluence as well as the harsh environment of an inertial fusion reactor chamber. We have explored the design options and responses of metal mirrors in a coordinated program of modeling, mirror fabrication and experiments. Our results indicate that grazing-incidence metal mirrors have the ability to survive the IFE environment while satisfying the requirements on beam quality necessary for successful target implosion. 1