Growth, spectral properties, and laser demonstration of Yb3+ doped K5Bi(WO4)0.22(MoO4)3.78 crystal

Abstract

A novel 15at. % Yb3+ ion doped K5Bi(WO4)0.22(MoO4)3.78(Yb: KBWM) crystal with a disordered structure is successfully grown by Czochralski (CZ) method. The crystal growth, structure, optical properties, and laser performance were investigated. With the introduction of the (WO4)2- anionic group, not only maintains the crystal structure of K5Bi(MoO4)4, but also results in a non-uniform broadening of the spectra. The absorption cross-section is 2.5 × 10−20 cm2 at 975 nm. The stimulated emission cross-section is 1.2 × 10−20 cm2 at 1014 nm, with a full width at half maximum (FWHM) of 47.2 nm. The fluorescence lifetime is 730.6 μs. Furthermore, continuous wave laser operations are achieved in Yb: KBWM crystal with different output coupler transmissions. Slope efficiency as high as 11.8% with respect to the pump power and an output power of 59.6 mW were achieved with a laser diode-pumped Yb: KBWM laser. The results show that the anion group modified crystal Yb: KBWM may be used in solid-state tunable and ultra-fast lasers.