Studies of temporal characteristics of all-solid-state, gain-switched Cr:forsterite laser

Abstract

A four-level rate-equation based model is presented to study the temporal dynamics of gain-switched Cr:forsterite laser. This model incorporates the effect of the excited-state absorption (ESA) present at the pump as well as the emitted wavelength from the forsterite laser. The value of the ESA cross-section at the pump wavelength (1064 nm) was experimentally obtained and utilized in the theoretical studies. The evolution of the upper laser level population and laser pulse inside the resonator cavity was numerically obtained by solving the rate-equations of the cavity photon density and population density. The Cr:forsterite laser pulse shows spiking behaviour as a consequence of the relaxation oscillation occurs during the buildup of the laser pulse inside the resonator cavity. The effect of several parameters related to pump pulse and cavity components on the output pulse parameters and the cavity buildup time were studied. The spiking behaviour in the output pulse profile of the Cr:forsterite laser was experimentally observed. The Cr:forsterite laser was pumped by the fundamental wavelength of Nd:YAG laser operated at 20 Hz pulse repletion rate in the confocal resonator cavity. The experimental results of pulse parameters were compared with the computed results and presented here.