1.65-μm Er:Yb:YAG diode-pumped laser delivering 80-mJ pulse energy

We demonstrate efficient lasing of bulk diode-pumped Er3+:Yb3+:YAG at 1.645 µm. The material is transversely pumped using three quasi-cw 960-nm laser diode arrays in a simple arrangement. In the free-running mode of operation, an output pulse energy of 79 mJ is obtained at 4.7 J of incident optical pump energy. The lasing threshold lies in the range 1.0 to 1.9 J in long-pulse operation, depending on pumping conditions, and optical slope efficiencies of 2.2% to 3.4% were measured with respect to the incident pump energy. Furthermore, initial Q-switching experiments with a Co:MALO saturable absorber yielded pulses of 1.7-mJ energy and 340-ns FWHM duration. As the reported laser setup also has an uncomplicated and compact design, it represents a good crystalline rare-earth candidate system with superior material qualities to compete against the established glass-host materials in the eye-safe wavelength range.