The influence of active ion concentration and crystal parameters on pulsed Cr:YAG laser performance

An experimental investigation of the effects of crystal characteristics on Cr:YAG laser performance was carried out. Slope efficiency, threshold, and gain-switching parameters are analysed in terms of Cr4+ ion concentration, parasitic loss, and excited state absorption. Laser tuning range and mode structure were examined in each case. Results are compared with the predictions of a rate equation model, which extends a simple gain-switching treatment to include excited state absorption and dynamic pump effects. A best fit to experimental data is used to predict Cr:YAG cross-sections within the wide range of published values. A crystal with low Cr4+ ion concentration gave higher output energy and broader tuning range than more recently developed heavily-doped material.