Investigation of a gain-switched Cr²⁺: ZnSe laser pumped by an acousto-optic Q-switched Ho : YAG laser

We demonstrate a gain-switched Cr²⁺ : ZnSe laser pumped by a high energy Ho : YAG laser. The maximum output power of 5.5 W in the spectrum range from 2450 nm to 2570 nm is obtained at a pulse repetition rate of 2 kHz, corresponding to a pulse energy of 2.75 mJ. With a volume Bragg grating (VBG) for compressing the linewidth, a 2.4 W output power with a narrow linewidth (< 1 nm) is obtained at 2570.5 nm. The pulse shapes obtained at different pump energies are also studied and analysed. A minimum pulse width of ~28.5 ns is achieved at a pump energy of 14.6 mJ, corresponding to a peak power of ~96.5 kW.