High-Efficiency High Repetition Rate Gain-Switched Lasers at 2.4-2.7 μm Based on Polycrystalline Cr2+:ZnSe Slabs with Undoped End-Cups Pumped at 2.1 μm by Ho3+:YAG Lasers

Efficient gain-switched laser operation at 2.4-2.7 μm was achieved in polycrystalline Cr
²⁺
:ZnSe slabs (with rectangular or zig-zag optical path configurations) pumped at 2.1 μm by the pulsed Ho
³⁺
:YAG laser with the repetition rate of 5-30 kHz. The lasing occurred at 2.4-2.6 μm or 2.65-2.7μm, depending on the cavity mirror reflections, temperature, and resonator design. The average oscillation power reached 2.7 W (at 2.65-2.7 μm) with a slope efficiency of ~40%,or 3.4 W(at 2.4-m2.6 μm) with a slope efficiency of ~50%AA.