Optical properties ofCu+ions inRbMgF3crystals

The absorption, emission, and excitation spectra, as well as the lifetimes, have been measured for ${\mathrm{Cu}}^{+}$ ions substituting for ${\mathrm{Rb}}^{+}$ ions in two different sites in ${\mathrm{RbMgF}}_3$ crystals. The (3d${)}^{10}$→(3d${)}^9$(4s) absorption transitions occur in the ultraviolet with optical emission at 450 and 575 nm. The two emission bands have been attributed to ${\mathrm{Cu}}^{+}$ ions occupying two different sites. From the results of polarized excitation experiments, the electronic structure of the crystal-field-split levels of the (3d${)}^9$(4s) configuration of ${\mathrm{Cu}}^{+}$ ions at the two sites can be determined. The 575-nm luminescence is quenched above 300 K. This quenching is ascribed to nonradiative multiphonon emission which is enhanced significantly by strong nonlinear electron-phonon coupling.