Color-Tunable Upconversion Luminescence in Er3+-Yb3+ -codoped Sodium Lutetium Fluoride Glass-ceramics

Abstract

In this work, the study of the near infrared to visible upconversion (UC) emission in transparent sodium lutetium fluoride glass-ceramics doped with ErF 3 and co-doped with YbF 3 is reported. Intense UC green and red emissions due to ( 2 H 11/2 , 4 S 3/2 ) →4 I 15/2 and 4 F 9/2 →4 I 15/2 transitions respectively together with a more weak blue emission due to the 2 H 9/2 →4 I 15/2 transition have been observed under excitation at 980 nm. The influence of Yb 3+ co-doping and excitation power density on the upconversion emissions is investigated. The addition of Yb 3+ ions greatly enhances the overall UC emission intensity and can be used to tune the UC emission from green to yellow due to an increase of the red-to-green ratio.