Orientation and polarization dependence of both the absorption and the laser efficiency around the optic axis in monoclinic Ho3+ :KYW
Résumé
A complete solid solution between the anion-deficient pyrochlore Ag2Sb2O6 and the ideal pyrochlore Cd2Sb2O7 has been synthesized through the standard solid state ceramic method. Each composition has been characterized by various different techniques, including powder X-ray diffraction, optical spectroscopy, electron paramagnetic resonance and 121Sb Mössbauer spectroscopy. Computational methods based on density functional theory complement this investigation. Photocatalytic activity has been studied, and transport properties have been measured on pellets densified by spark plasma sintering. The analysis of the data collected from these various techniques enables a comprehensive characterization of the complete solid solution and revealed an anomalous behavior in the Cd-rich end of the solid solution, which has been proposed to arise from a possible radical O− species in small concentrations.
We report on the absorption profile of the monoclinic holmium-doped KY(WO4)2 crystal near the optic axis for the maximal absorption wavelength at 1960 nm. The full angular distribution of the absorption coefficient at the vicinity of such optical singularity has been experimentally and numerically investigated. Furthermore, laser experiments along the optic axis have been carried out. So-called conical refraction laser and classical Gaussian laser operation are compared near the optic axis, taking into account the complex absorption profile.