Thermally enhanced frequency upconversion in Nd~(3+)-doped fluoroindate glass

摘要

Multiphonon assisted frequency upconversion was observed in a Nd~(3+)-doped fluoroindate glass pumped at 866 nm. A near-infrared upconverted emission at 750 nm with a peculiar linear dependence with the laser intensity was observed and explained. The intensity of the upconverted emission experienced a 40-fold enhancement when the sample's temperature was varied from 298 to 498 K. A rate equation model that includes light pumping and multiphonon absorption via thermally coupled electronic excited states of Nd~(3+) was used, describing quite well the experimental results.