Judd--Ofelt analysis of spectra and experimental evaluation of laser performance of Tm³⁺ doped Lu₂SiO₅ crystal

This paper reports that the Tm^3 + :Lu_2SiO_5 (Tm:LSO) crystal is grown by Czochralski technique. The room-temperature absorption spectra of Tm:LSO crystal are measured on a b-cut sample with 4 at.% thulium. According to the obtained Judd--Ofelt intensity parameters \varOmega _2=9.3155\times 10^ - 20 cm^2, \varOmega_4=8.4103\times 10^ - 20 cm^2, \varOmega_6=1.5908\times 10^ - 20 cm^2, the fluorescence lifetime is calculated to be 2.03 ms for ^3F_4 \to ^3H_6 transition, and the integrated emission cross section is 5.81\times 10^ - 18 cm^2. Room-temperature laser action near 2 \mu m under diode pumping is experimentally evaluated in Tm:LSO. An optical-optical conversion efficiency of 9.1% and a slope efficiency of 16.2% are obtained with continuous-wave maximum output power of 0.67 W. The emission wavelengths of Tm:LSO laser are centred around 2.06 \mu m with spectral bandwidth of \sim 13.6 nm.