Abstract
Through thermal treatment of a fluoroaluminosilicate glass codoped with Er3+‐Yb3+ at a suitable temperature, microcrystallites were successfully precipitated in the glass matrix but little change was observed in the optical transmission spectra even around the ultraviolet edge, meanwhile the green upconversion luminescence due to the 4S3/24I15/2 transition of Er3+ increased by a factor of ∼100 when a 0.97 μm laser diode (LD) (5 mW) was used for excitation. The infrared to green or to red upconversion efficiencies for the vitroceramics are evaluated to be nearly 2 or 10 times as high as fluoride glasses, respectively. Also higher mechanical and chemical stabilities and laser damage threshold over fluoride glasses or crystals are expected for the vitroceramics.