SUPERPOLISHED SILICON-CARBIDE MIRROR FOR HIGH-POWER OPERATION OF EXCIMER LASERS IN A VACUUM ULTRAVIOLET SPECTRAL RANGE

We demonstrate the usefulness of a high-quality SiC mirror for the high-power operation of vacuum ultraviolet lasers. A void free SiC film of 400-μm thickness was deposited onto a high-purity graphite substrate by chemical vapor deposition. The super-polished SiC mirror, whose surface roughness was 0.2 nm rms, was used as a cavity reflector of a high-power Ar excimer laser, which operates at 126 nm. The highest output energy of 400 mJ/cm2 per pulse, which corresponds to the energy density of 1 J/cm2 on the SiC mirror surface, has been obtained without any damage to the SiC mirrors.