We report room-temperature continuous-wave upconversion laser emission on the green transition <sup>4</sup><i>S</i><sub>3/2</sub>→<sup>4</sup><i>I</i><sub>15/2</sub> in Er(1%), Yb(3%):YLiF<sub>4</sub> at 551nm. Green laser operation was obtained for titanium–sapphire pump wavelengths continuously tunable between 955 and 974.5nm. Codoping with Yb<sup>3+</sup> resulted in a more efficient excitation of the upper laser level by upconversion processes. The maximum green laser output power was 37mW at an incident titanium–sapphire pump power level of 1580mW at 966nm.
© 1997 Optical Society of America
P. E.-A. Möbert, E. Heumann, G. Huber, and B. H. T. Chai, "Green Er3+:YLiF4 upconversion laser at 551nm with Yb3+ codoping: a novel pumping scheme," Opt. Lett. 22, 1412-1414 (1997)