A 1-kW radially polarized thin-disk laser

In the present paper two techniques which were applied to high power Yb:YAG thin-disk laser systems for the generation of radially polarized beams is discussed. In the first approach, the rear mirror of a two-disk laser system was replaced by a polarization selective grating mirror. The polarizing effect of this element is achieved by a waveguide coupling mechanism which leads to a reduction of the reflection coefficient of the undesired polarization state. The second approach is based on an extra-cavity linear-to-radial polarization converter. The LRPC was tested by directing the collimated beam of a fiber-coupled high-power thin-disk laser linearly polarized by a conventional thin-film polarizer onto the element. The design, characterization as well as the laser operation tests of the intracavity polarizing grating mirror and of the linear-to-radial polarization converter is discussed.