Temperature-dependent evaluation of Nd:LiCAF optical properties as potential vacuum ultraviolet laser material

Abstract We investigate the temperature-dependent optical properties of Nd 3+ -doped LiCaAlF 6 (Nd:LiCAF) in the vacuum ultraviolet (VUV) region. The 172-nm absorption edge does not seem to experience any significant blue shift as temperature is decreased from room temperature down to 30 K. This is confirmed by excitation spectra for the same temperature range. Several energy levels in the excited state configuration are observed. Based on these energy levels, the dominant emission peak at 177 nm is assigned to the allowed dipole transition from the 4f 2 5d configuration of Nd 3+ and the 4 I 11/2 level of the 4f 3 ground state configuration. The position of the dominant 177-nm emission peak appears to be fixed across the temperature range considered. Our results suggest that the spectral overlap between the excitation and emission spectra should not increase as temperature is raised, possibly making Nd:LiCAF a potential VUV laser gain medium operating at room temperature.