Polarized spectral properties of Tm 3+:K 5Bi(MoO 4) 4 crystal

Abstract

Trivalent thulium-doped K 5Bi(MoO 4) 4 single crystals were grown by the Czochralski method. Its polarized absorption and fluorescence spectra and fluorescence decay curves were recorded at room temperature. On the basis of the Judd–Ofelt theory, the spectral parameters of the Tm 3+:K 5Bi(MoO 4) 4 crystal were calculated. The cross relaxations between Tm 3+ ions were analyzed. The emission cross sections of the 3F 4 → 3H 6 transition were obtained by the Fuchtbauer–Ladenburg formula and then the gain cross sections around 1.9 μm were calculated. The peak emission cross section and width of emission band around 1.9 μm are comparable to those for Tm 3+:YAG and the tunable range is about 280 nm for the potential ∼1.9 μm laser operation via the 3F 4 → 3H 6 transition.