Diffractive Devices In High Power Laser Beam Handling

Diffraction from structured surfaces is discussed as a new principle in high power laser beam optics. Useful properties of structured surfaces include, for example, polarization anisotropy, diffractive beam splitting and diffractive attenuation. Since these surfaces can be fabricated from low-loss materials, e.g. metals, the intrinsic absorption can be low enough to allow operating power levels high in the multikilowatt range. Several practical devices for high power laser beam handling can be based on diffractive concepts. For example, linear and circular polarizers can be fabricated as all-metal mirrors. These can be used both intra-and extracavity, and can be integrated into focusing surfaces. Diffractive loss from all-metal perforated screens has already been used to develop a precision step attenuator with applications in beam diagnostics as well as in laser process studies.