Room-temperature continuous-wave Er/sup 3+/:LiLuF/sub 4/ upconversion laser at 552 nm

Summary form only given. Upconversion lasers need host materials with low effective phonon energies to minimize the non-radiative decay rates of the rare-earth dopant excited energy levels involved in the multi-step pumping process. Room-temperature continuous-wave lasing at 552 nm was demonstrated under Ti:Al/sub 2/O/sub 3/ on pumping at either 810nm or 974nm. Maximum output power of 72 mW was obtained in a nearly concentric resonator with the pump source tuned to 974nm. At this output power level, the incident pump power was 2.5 W corresponding to 450 mW of absorbed power.