3.1 μm mid-infrared fluorescence enhancement by energy transfer in Bi+/Er3+ co-doped fluorozincate glasses

This work investigates the mid-infrared emission from Bi+/Er3+ co-doped zinc fluoride glasses. The fluorozincate glasses were fabricated by employing high-temperature melt-quenching technology. Under a 980 nm laser diode pump, an intense broadband mid-infrared emission was observed at 3.1 mu m with the full width at half maximum (FWHM) about 164 nm. A prominently enhanced mid-infrared fluorescence emission intensity was achieved by drawing Bi2O3 into the zinc fluoride glasses. In addition, up-conversion and near-infrared emission using different Bi2O3 ion doping concentrations were studied. Meanwhile, the fluorescence lifetimes of the Bi+/Er3+ co-doped fluorozincate glasses were calculated at 3.1 mu m up to 1.17 ms, which was significantly prolonged as compared to Er3+ single-doped sample. The mechanism of energy transfer between Bi+ and Er3+ ions was further examined through the energy level transition process. The outcome suggested that the Bi+/Er3+ co-doped zinc fluoride glasses may be a prospective medium for 3.1 mu m laser applications.