2 µm lasing from Tm3+-doped PbO-PbF2-Bi2O3-Ga2O3 glass microspheres.

Whispering gallery mode (WGM) lasers at ∼2µm are demonstrated in PbO-PbF2-Bi2O3-Ga2O3 (PBG) heavy metal oxyfluoride glass microspheres. A 793 nm diode laser is used to pump the PBG microsphere and achieve single-mode and multimode WGM lasing. The fluorescence spectra of Tm3+-doped PBG glasses are measured under 793 nm diode laser pumping. The maximum absorption and emission cross sections of Tm3+:3F4→3H6 are calculated to be 8.23×10-21 and 4.42×10-20cm2, respectively. The experimental results indicate that these PBG glass microspheres could become an important photonic component for infrared laser applications.