Upconversion laser emission from Yb^3+-sensitized Tm^3+ in BaY_2F_8

Abstract

Room-temperature upconversion laser operation has been demonstrated at 456, 482, 512, 649, and 799 nm in the ytterbium-sensitized thulium system in BaY2F8. With 960-nm titanium–sapphire laser pumping, cw operation of the 649- and the 799-nm upconversion laser transitions is observed. We believe that this is the first observation of laser emission on the 799-nm transition from 1G4 and the 512-nm transition from 1D2 in a bulk-crystal sample. At reduced temperatures cw or quasi-cw laser operation is obtained on the 456-, the 482-, and the 512-nm transitions. Room-temperature diode-laser pumping has been demonstrated for the 456-, the 512-, and the 649-nm transitions.