Low-loss resonant grating mirrors for polarization shaping in high power solid-state lasers

The generation of laser beams with axially-symmetric (radial or azimuthal) polarization states became very attractive during the last years for many applications like material processing, optical data storage or high resolution optical microscopy. In this contribution we report on the specific requirements and properties of a circular polarizing grating integrated to a standard multilayer HR mirror to generate radially and azimuthally polarized radiation in a high power Yb:YAG thin-disk laser. The polarizing effect is based on an intra-cavity reflectivity difference between the two orthogonal polarization states which is induced by a waveguide coupling mechanism between the incident free space beam and leaky wave-guide modes in the multilayer mirror. In the case of axially-symmetric polarization states, the required local reflectivity difference for TE (electrical field parallel to the grating lines) and TM (electrical field perpendicular to the grating lines) polarized incident radiation is locally introduced using a circular grating The design results as well as the complete characterization and laser tests of the elements will be presented and discussed in the present talk.