Bashir, DanishBoubekraoui, AyoubMourkioti, GeorgiaLi, FangfangKarvinen, PetriKuittinen, MarkkuMackenzie, Jacob. I.Graf, ThomasAbdou Ahmed, Marwan2024-12-182024-12-1820231432-06490946-21711914925017http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-ds-154575http://elib.uni-stuttgart.de/handle/11682/15457http://dx.doi.org/10.18419/opus-15438We report on the design, fabrication, and implementation of a single-layer resonant waveguide-grating (RWG) mirror on a sapphire substrate. Our goal is to enhance these optics capability to withstand high intra-cavity power densities by exploiting the superior thermal properties of sapphire. The RWG was implemented as an intra-cavity folding mirror in an Yb:YAG thin-disk laser to generate linearly polarized and spectrally stabilized radiation. A linearly polarized output power of 191 W with an optical efficiency of 39% was obtained in multi-mode operation. This corresponds to a power density of 52 kW/cm 2 on the RWG, for which the increase of its surface temperature was measured to be 12 K, which resulted in a 46-fold reduction of the surface temperature rise dependence on the intra-cavity power density with respect to what has been reported for a RWG on a fused silica substrate. In near fundamental-mode operation, a linearly polarized emission with an output power of 90 W, an optical efficiency of 30%, and a spectral bandwidth of 28 pm FWHM was obtained.eninfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by/4.0/620article2024-11-02