High-repetition-rate, high-average-power, diode-pumped 2.94-mu m Er : YAG laser

We have demonstrated more than 3 W of average-output power from a 2.94-mum quasi-cw diode-pumped total internal reflection (TIR) Er:YAG laser operatin g at 100 Hz with a 4% duty cycle. Moreover, repetition rates of up to 600 H z at more than 1.2-W output power have been achieved. The cavity consists o f a plane-mirror resonator of 40-mm length and uses three of five TIR regio ns within the laser crystal as pump facets to efficiently couple the pump e nergy into the resonant laser mode. Differential efficiencies of up to 18.3 % have been achieved at an optimum pump pulse width in the range of 300 mus . (C) 2001 Optical Society of America.