High-performance intra-cavity polarization- and wavelength-selective grating-mirrors for Yb:YAG thin-disk lasers

The present contribution reports on the modelling, fabrication, as well as the intra-cavity characterization of fully dielectric grating-mirrors for Yb:YAG thin-disk lasers. By integrating a low-index leaky-mode waveguide and a sub-wavelength diffraction grating onto an HR mirror, such devices achieve high diffraction efficiencies, in our case >99.8% in the - 1^st order. Used as simple one-to-one replacement for laser cavity end mirrors, they allow a highly efficient generation of beams with very narrow spectral bandwidth and high-polarization purity. Since the grating-waveguide-mirrors (GWM) are used in Littrow configuration, they also permit to tune the wavelength of the emitted laser beam. Therefore they can replace a combination of etalons, birefringent filters, Brewster plates and/or thin-film polarizers usually employed for these tasks.