Optimization of quasi-three level end-pumped Q-switched lasers

Equations describing the pump excitation and Q-switched energy extraction of end-pumped, quasi-three level laser systems are collected. A transcendental expression relating the Q-switched laser output energy to the laser´s initial gain and cavity transmission which is valid for arbitrary output coupling is derived. This expression simplifies sensitivity and optimization studies of such systems. A first order ordinary differential equation is derived which describes the rod-integrated excited state number density resulting from an arbitrary pump excitation pulse, The equation is valid for both single pass and double pass pump geometries. To illustrate the utility of the collected set of equations an end-pumped joule class, Q-switched Yb:YAG oscillator is optimized and studied