Frequency upconversion inEr3+-doped fluoroindate glasses pumped at 1.48 μm

We report on efficient frequency upconversion in ${\mathrm{Er}}^{3+}$ -doped fluoroindate glass. The process is observed under 1.48 μm laser diode excitation and results in fluorescence generation in the range from ultraviolet to near-infrared radiation. The study was performed for samples containing 1, 2, and 3 ${\mathrm{ErF}}_3$ mol % in the range of temperatures from 24 to 448 K. The upconverted signals were studied as a function of the laser intensity, and their dynamical behavior is described using a rate equation model which allows us to obtain the energy transfer rates between ${\mathrm{Er}}^{3+}$ ions in pairs and triads.