Thermal properties and polarized spectral analysis of Tm3+:SrWO4 crystal

Tm3+:SrWO4 crystal of good optical quality with sizes of 15 mm×60 mm was grown successfully by Czochralski technique method. The orientation procedure of this crystal was discussed. The principal coefficients of thermal expansion along (001), (010), (100) directions were precisely measured to be 2.73×10−5, 1.00×10−5, 1.05×10−5 °C−1, respectively. Based on the Judd–Ofelt theory, we obtained the three intensity parameters: Ω2=7.41×10−20, Ω4=0.25×10−20, and Ω6=1.71×10−20 cm2. The radiative probabilities, radiative life times, and branch ratios of Tm3+:SrWO4 were calculated. The room temperature polarized fluorescent spectra and fluorescent decay curve were measured. The luminescent quantum efficiency of the 3H4 level was investigated and the quantum efficiency is determined to be approximately 69.84% for this material.