Optical properties of Sm3+ doped Ca3(Nb,Ga)5O12 and Ca3(Li,Nb,Ga)5O12 single crystals

Sm3+ doped partially disordered calcium-niobium-gallium-garnet (CNGG) and calcium-lithium-niobium-gallium-garnet (CLNGG) single crystals were grown by the Czochralski method. Spectroscopic characteristics of Sm:CNGG and Sm:CLNGG single crystals were obtained by high-resolution absorption and emission spectra and emission dynamics measurements. Partial energy levels of Sm3+ doped CNGG and CLNGG were extracted from the measured spectra. The Judd-Ofelt theory has been applied to evaluate the Ωt (t=2, 4, 6) intensity parameters, radiative transition rates Ar, branching ratios β, and radiative lifetime τr of the fluorescent Sm3+ 4G5/2 level. The emission cross-sections for the 4G5/2→6HJ (J=5/2, 7/2, 9/2) transitions of special interest for visible laser application were obtained by the Fuchtbauer - Ladenburg equation. The interaction between Sm3+ ions is dipole-dipole type and the CDA microparameter for both crystals was calculated based on Inokuti-Hirayama model.