Growth, optical properties and laser performance of a novel Yb3+-doped (Sc0.2Y0.8)2SiO5 composite laser crystal

A novel Yb 3+ -doped (Sc 0.2 Y 0.8 ) 2 SiO 5 (Yb:SYSO) laser crystal with bulk size was firstly grown by the Czochralski growth method, exhibiting an X-ray rocking curve (XRC) full width at half maximum (FWHM) of only 0.034°. The optical properties, including refractive index, absorption spectrum, emission spectrum and fluorescence lifetime were systematically measured. The Yb:SYSO crystal exhibits a 40 nm FWHM absorption band at 972 nm, with an absorption cross-section of 0.72 × 10 −20 cm 2 , and a 76 nm FWHM emission band at 1040 nm, with an emission cross-section of 1.13 × 10 −20 cm 2 . The fluorescence lifetime is determined to be 1.05 ms. The superposition model (SM) was employed to fit the spin-orbit parameters ( ξ) and crystal field parameters ( ) of Yb:SYSO, achieving good consistency between the calculated and experimental crystal field levels. Furthermore, the continuous-wave (CW) and acousto-optic Q-switched (AOQS) laser operation of the Yb:SYSO crystal was demonstrated. In the CW laser experiments, the Yb:SYSO crystal delivers a maximum output power of 8.48 W at 1082.9 nm, with a slope efficiency of 46.86% and an optical-to-optical efficiency of 44.94%. Under AOQS operation, the Yb:SYSO laser produces up to 165 μJ pulse energy with 178 ns minimum pulse width at pulsed repetition frequency of 2 kHz, corresponding to a peak power of 927 W. The results indicate that Yb:SYSO crystal is a promising laser crystal material.