Spectroscopic properties of thulium doped (Lu0.25Gd0.75)2SiO5 (LGSO) single crystals

In this work, spectroscopic properties of (Lu0.25Gd0.75)2(1-x)Tm2xSiO5 (x = 0.04 and 0.005) single crystals were investigated. The material was found to be biaxial, exhibiting strong optical anisotropy, as clearly demonstrated in polarized absorption and emission spectra. Data from room temperature polarized absorption spectra were used in calculations within the phenomenological Judd-Ofelt model. The intensity parameters Ωt were established at Ω2 = 3.24 (±0.58), Ω4 = 2.96 (±0.24) and Ω6 = 0.86 (±0.14) [10−20 cm2]. The values of fluorescence lifetimes of the 1D2 and 1G4 levels were measured and subsequently compared with those calculated using the Judd-Ofelt theory. The strong absorption bands located at wavelengths around 355, 460 and 790 nm, related to the 3H6 → 1D2, 1G4, 3H4 transitions, were found suitable for optical pumping of the investigated material. The characteristics of emission spectra recorded in the blue (ca. 455 nm) and IR (ca. 1750 nm) regions indicate that further investigations of stimulated emission within those wavelength ranges are well justified and can be considered promising.