Er/sup 3+/:YAlO/sub 3/ upconversion laser

Upconversion lasing in Er:YAlO/sub 3/ is reported. Laser emission was produced using both sequential two-step pumping and cross-relaxation energy transfer. In addition, photon avalanche upconversion pumping was demonstrated. Selection among these pumping mechanisms is determined by the pump wavelength, and laser operation was obtained with excitation between 785 nm and 840 nm. The highest laser output power was achieved at 34/spl deg/K, where 918 mW of pump power at 807 nm produced 121 mW of TEM/sub 00/ emission. The optical conversion efficiency was 13%. Repetitively Q-switched operation is reported, and the temporal- and temperature-dependence of the laser output is discussed.<
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