Al-Zr fluoride glass for Ho^3+-Yb^3+ green upconversion

Abstract

A fluoroaluminozirconate glass was compared with a fluorozirconate and a fluoroaluminate glass as a host material for upconversion emissions in a Ho3+–Yb3+-codoped system. The green emission of 543 nm is 50% stronger in fluoroaluminozirconate than in fluorozirconate. This is because the emission is primarily governed by the Yb3+–Ho3+ energy-transfer rate rather than by the multiphonon decay rate of the emitting level. The optimum concentrations of Ho3+ and Yb3+ ions for emission intensity are 0.2 and 3.0 cationic %, respectively, at a pumping density of 560 W/mm2. By tuning a pump wavelength we also observed intense UV–blue upconversion emissions from the fluoroaluminozirconate fiber sample.