Long lifetime of dual rare earth active centers in novel multi-component fluoride glasses for mid-infrared laser applications
A group of novel multi-component fluoride glasses simultaneously activated using two mid-infrared (MIR) luminescence centers Er3+ and Ho3+ with different ratios were synthesized to systematically investigate their radiation and energy transfer processes and explore their potential MIR applications. Differential thermal analysis and transmission curve indicate that this new component glass has good thermodynamic properties and high MIR transmission. Fluorescence spectra show that Ho3+ has a strong quenching effect on the lower energy level of the 2.7 μm Er3+ emissions, whereas the quenching effect on the upper energy level is weak, suggesting that Ho3+ can be used as sensitizing ions in a 2.7 μm Er3+ laser operation. For the MIR band, the effective linewidth of co-doped Er3+/Ho3+ sample increases with the Er3+ concentration, which has potential application for use in MIR fiber amplifiers and pulsed laser generation. The fluorescence decay curves show that in this multi-component fluoride glass matrix the lifetime of each band is longer than that of the other substrates. The lifetime (5.95 ms) of the 2.7 μm Er3+ obtained in this experiment is noticeably the longest among other reported glass systems. Moreover, the radiation and energy transfer mechanisms are given based on the fluorescence spectra and fluorescence decay curves.