Investigation of sol-gel antireflection coatings

Very high power laser systems present material design challenges which often approach the inherent optical survival strength of components. Optical coatings in the UV region suffer from anomalously high absorption and scattering in the deposited layers. The losses caused by these effects are often unacceptable or, in the case of absorption, usually fatal to the absorbing coatings. No metals exist that have high enough reflectivities in the UV to serve as uncoated mirrors as they normally do in the CO2 region of the infrared. Adequate multilayer dielectric coatings and reflection suppressing antireflective coatings in that wavelength range are important for the development and utilization of UV lasers. Antireflective properties of gradient index designs were rediscovered and their potential for resolving UV laser design difficulties was tested. The antireflective properties are attained on glass or fused silica surfaces by chemical surface treatments.