Free-running and Q-switched performance of a diode-pumped Er:Yb:YAG laser emitting at 1.65μm

Pulsed Er3+:Yb3+:YAG is a novel crystalline diode-pumped laser capable of delivering high pulse energies in the 1.5-1.7 mu m "eye-safe" region. This work reports efficient lasing in long-pulse and in Q-switched mode, with pulse energies in the order of 10's of mJ, employing standard 960-nm quasi-cw semiconductor laser arrays in a direct transverse diode-pumping configuration. In free-running mode, 83mJ output, 15% slope efficiency and 0.24J pump threshold have been attained. Q-switched operation was realized with a "frustrated total internal reflection (FTIR)" device, yielding 12.5mJ single pulses of 41-ns FWHM duration with smooth temporal and spatial profiles. Pump temperature-tuning and pulse duration effects on laser performance were also investigated, whereas pumping parameters optimizing pulse energy and efficiency were determined.