Up-conversion characteristics of Er3+ in transparent oxyfluoride glass–ceramics

Up-conversion characteristics of Er3+ under 800 nm excitation are clarified for 30SiO2 ⋅15AlO1.5⋅28PbF2⋅22CdF2⋅(5−x)GdF3⋅xErF3 (x=0.3–5) transparent glass–ceramics, which are composed of fluoride nanocrystals and oxide glass matrices. Strong up-conversion emissions at around 525, 550, and 660 nm, and weak up-conversion emissions at around 410, 450, and 490 nm are observed. The intensities of up-conversion emissions at around 550 and 660 nm change remarkably with ErF3 contents from 1 mol % to 5 mol %: emission at 550 nm decreases and one at 660 nm increases with increasing ErF3 content. These features can be explained by Er3+ up-conversion mechanisms which were proposed for ZrF4-based glasses.