Spectroscopic and crystal-field analysis of new Yb-doped laser materials

Crystal-field effects are very important as far as laser performances of Yb-doped materials are concerned. In order to simplify the interpretation of low-temperature spectra, two tools derived from a careful examination of crystal-field interaction are presented. Both approaches are successfully applied in the case of new Yb-doped materials, namely Ca₃Y₂(BO₃)₄ (CYB), Ca₃Gd₂(BO₃)₄ (CaGB), Sr₃Y(BO₃)₃ (SrYBO), Ba₃Lu(BO₃)₃ (BLuB), Y₂SiO₅ (YSO), Ca₂Al₂SiO₇ (CAS) and SrY₄(SiO₄)₃O (SYS). The ²F_7/2 splitting is particularly large in these materials and favourable to a quasi-three-level laser operating scheme. Calculations performed using the point charge electrostatic model for these compounds and using a consistent set of effective atomic charges confirm the experimental results. This should permit to use this model in a predictive approach.