Study of Fe:ZnSe Laser Exited by Diode Side-Pumped Er:YAG Laser

The performance of a Fe:ZnSe laser was investigated in different schemes of excitation by a pulsed diode side-pumped Er:YAG laser. At the temperature of liquid nitrogen, the Fe:ZnSe laser, pumped by a free running 360-mu s Er:YAG laser and demonstrated a pulse energy of 53 mJ with a slope efficiency of 42% relative to absorbed pump energy. When operating at room temperature, two optical schemes were considered. In the first one, the Fe:ZnSe laser crystal was pumped by a Q-switched Er:YAG laser with a passive shutter based on an additional Fe:ZnSe crystalline plate, and the cavities of both lasers were independent. In the second scheme, the cavities of the Fe:ZnSe and Er:YAG lasers were coupled, and the Fe:ZnSe crystal simultaneously served as an active element of the Fe:ZnSe laser and a passive shutter of the Er:YAG laser. Pulses with a duration of less than 200 ns and an energy of similar to 1 mJ were obtained from the Fe:ZnSe laser with a repetition rate of up to 50 kHz. The experimental waveforms of the laser pulses were approximated by rate equations.