Pr:YLF, intracavity-pumped, room-temperature upconversion laser

Cw room-temperature upconversion laser operation is reported in Pr:YLF at 640 and 607 nm. An intracavity-pumping scheme that uses a Yb:YAG laser operating at 1030 nm to pump the weak H-3(4) --> (1)G(4) ground-state transition of Pr:YLF is used to populate the intermediate metastable level. An excited-state absorption at 867 nm is then used to populate the P-3(0) and P-3(1) upper states. An average output power of 3.5 mW was obtained at 607 nm, with a combined input pump power of 2.5 W. (C) 1996 Optical Society of America.