Spectral properties of Tm3+-doped LiLa(MoO4)2 crystal

Detailed spectral properties of uniaxial Tm 3+ :LiLa(MoO 4 ) 2 crystal have been investigated, including the polarized absorption spectra, polarized emission spectra, and fluorescence decay. Especially, the fluorescence spectra and decay curve of the upper level for ∼2.0 μm laser, 3 F 4 multiplet, were measured. The re-absorption of the emission from the 3 F 4 multiplet and the cross-relaxation between Tm 3+ ions were analyzed. The emission cross-sections of the 3 F 4 multiplet were obtained by the reciprocity method and then the gain cross-sections around 2.0 μm were calculated. The maximum absorption cross-section of the pump band is 4.04 × 10 −20 cm 2 at 795 nm with a bandwidth of 8 nm, which means this crystal is suitable for laser diode pumping. All the results show that Tm 3+ :LiLa(MoO 4 ) 2 crystal is a promising candidate for gain medium of ∼2.0 μm laser.