Emission kinetics of lasers pumped by short pulses

An analysis is made of the emission kinetics of lasers when the length of the active element is much shorter than the resonator length and the time of photon transit through the active element is much shorter than the lifetime of the upper luminescence level. The rate equations for the level populations of the active element and the transport equations for the intensities of the radiation and pump fluxes are used to derive a differential equation with a delaying argument for the kinetics of the integrated population of the active element on exposure to the pump flux. Recursion relationships which link the radiation fluxes and the integrated population are obtained. For a laser pumped by short pulses (the pump duration is much shorter than the lifetime of the upper luminescence level), the results of a numerical solution of this problem are presented and analyzed.