Laser performance of a 966 nm LD side-pumped Er,Pr:GYSGG laser crystal operated at 2.79 μm.

We demonstrate a 966 nm laser diode (LD) side-pumped Er,Pr:GYSGG laser crystal operated at 2.79 μm under a high repetition rate. The lifetimes of the upper level I4 and lower level I4 are 0.66 and 0.85 ms, respectively. The laser performance under different repetition rates and pulse widths is experimentally studied with the optimal cavity structure. A maximum output power of 8.86 W is achieved at 125 Hz and 200 μs pulse widths, corresponding to the slope efficiency of 14.8% and electrical-to-optical efficiency of 7.7%. With increasing frequency from 50 to 200 Hz, the slope efficiency varies from 24.7% to 11.7% operated at a 125 μs pulse width. Moreover, the Mx2/My2 factors of 7.52/7.59 and Θ/Θ far-field divergences of 16.1/16.5 mrad are also measured. The results indicate that a high-performance 2.79 μm laser could be realized on the Er,Pr:GYSGG radiation resistant crystal by deactivation and LD side-pumping.