Upconversion luminescence properties of Er3+ doped GeS2-Ga2S3-KCl chalcohalide glasses

Er3+ ions doped chalcohalide glasses with the composition of 56GeS2-24Ga2S3-20KCl were fabricated by a melt-quenching method. Under 800 nm laser excitation, strong green emissions centered at 525 nm and 550 nm and weak red emission centered at 660 nm were observed, which were assigned to 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2 transitions, respectively. The intensity reached maximum when the Er3+ ions concentration was 0.1 mol%. The possible upconversion luminescence mechanism was proposed from the discussion on the above results as well as the results of lifetimes of the metastable 4I13/2 level and local environment of Er3+ ions. It is found that chalcohalide glass can be good host materials for upconversion luminescence.