Spectroscopy of potential laser material Yb3+(4f13) in NaBi(WO4)2

Abstract We report the solid-state synthesis, growth, and spectroscopic properties of single-crystal NaBi(WO4)2 containing Yb3+ ions. The tetragonal crystal phase is disordered, resulting in substantial inhomogeneous broadening of spectra. The site symmetry for the Yb3+ ions can be approximated by D2d symmetry according to a quasi-center model, which has recently proven quite satisfactory for the analysis of Er3+ crystal field splittings in the same host. We use the Er3+ results to estimate crystal field parameters for Yb3+, and compare the splittings predicted for these parameters with observed spectra. We also report the fluorescence lifetime at cryogenic and room temperatures, and give estimates for the stimulated emission cross-section and radiative lifetime of Yb3+ emission. The results indicate that this material may have promise as a gain medium for a smoothly tunable 1 μm laser.