Polarization-dependent angular distribution of the absorption behavior in ytterbium-doped monoclinic LYB and LGB laser crystals

International audience; We detail the full characterization of the anisotropy of the absorption properties of two different Yb-doped monoclinic borate compounds under polarized light. The studied crystals are Li6(Gd)0.75Yb0.25(BO3)3 and Li6Y0.75Yb0.25(BO3)3, respectively, and were grown by the Czochralski method. We focused on the study of their absorption at the zero line transition as a function of the polarization direction of the incident light for two different crystal cuts of each compound. We discuss the different eigenframes that must be considered in these materials, due to their monoclinic character, as well as the optimum crystal orientation for the considered absorption and show the potential influences when used as laser materials.