40  kHz, 20  ns acousto-optically Q-switched 4  µm Fe:ZnSe laser pumped by a fluoride fiber laser.

An actively Q -switched mid-infrared Fe:ZnSe laser pumped by a continuous wave fluoride fiber laser has been developed. Stable operation with a pulse duration of 20 ns and a repetition rate of 40 kHz at 4 µm was achieved. The maximum peak power was 1.1 kW. The high-repetition rate, high-peak power nanosecond pulsed laser, which has been created for the first time, to the best of our knowledge, in an actively Q -switched Fe:ZnSe laser, should prove a suitable light source for laser processing and molecular sensing.