Energy transfer assisted frequency upconversion in Ho3+ doped fluoroindate glass

Experimental results are reported which show a strong evidence of energy transfer between Ho3+ ions in a fluoroindate glass excited by a pulsed laser operating at 640 nm. We identified the origin of the blue and green upconverted fluorescence observed as being due to a Ho3+–Ho3+ pair interaction process. The dynamics of the fluorescence revealed the pathways involved in the energy transfer assisted upconversion process.