CW room-temperature blue upconversion fibre laser

The authors report what they believe to be the first single-wavelength pumped, CW, room-temperature, blue upconversion laser. This 480 nm laser uses Tm/sup 3+/ as the active ion in a fluorozirconate glass fibre. Up to 60 mW of output power has been observed with a slope efficiency of 18% with respect to coupled pump power.< >