Theoretical characteristics of mid-infrared gain switched pulsed iron-doped ZnSe laser

We report a four-level theoretical model revealing the laser kinetics of a gain-switched pulsed Fe2+:ZnSe laser that is established for the first time, to the best of our knowledge. The experimental results agree with the theoretical primary spike pulse and relaxation oscillation phenomenon of pulse. Furthermore, the effects of temperature, doping concentration, and the output coupler reflectivity on the performance of the pulsed Fe2+: ZnSe laser are simulated using the proposed model. The simulated results indicate that the laser efficiency is higher at low temperature and high Fe2+ concentrations, and the optimal output coupler reflectivity is ~23% at 77 K.