CW laser oscillation on both the F-4(3/2)-I-4(11/2) and F-4(3/2)-I-4(13/2) transitions of Nd3+ ions using a fluoride glass microsphere

We have succeeded in continuous-wave laser oscillation on both the F-4(3/2)-I-4(11/2) and F-4(3/2)-I-4(13/2) transitions of Nd3+ ions in fluoride glasses formed into microspheres. A glass microsphere was excited by a Ti:Al2O3 laser tuned to 800 nm. The thresholds of the laser oscillation were found to be 5 and 60 mW for the F-4(3/2)-I-4(11/2) (1051 nm) and F-4(3/2)-I-4(13/2) (1334 nm) transitions, respectively. The average values of the spacings between resonance peaks are in good agreement with the calculated ones, based on Mie scattering theory. Hence, it can be suggested that these peaks be assigned to the whispering gallery modes.