Enhancement of upconversion luminescence in Tm 3+/Er 3+/Yb 3+-codoped glass ceramic containing LiYF 4 nanocrystals

Abstract

A transparent Er 3+–Tm 3+–Yb 3+ tri-doped oxyfluoride glass ceramics containing LiYF 4 nanocrystals were prepared. Under 980 nm laser diode (LD) pumping, intensive red, green and blue upconversion (UC) was obtained. The blue, green, and red UC radiations correspond to the transitions 1 G 4→ 3 H 6 of Tm 3+, 2 H 11/2/ 4 S 3/2→ 4 I 15/2, and 4 F 9/2→ 4 I 15/2 of Er 3+ ions, respectively. This is similar to that in Tm 3+–Yb 3+ and/or Er 3+–Yb 3+ co-doped glass ceramics. However, the blue UC radiations of the Er 3+–Yb 3+ co-doped glass ceramics is two-photon process due to cooperative energy transfer. The UC mechanisms were proposed based on spectral, kinetic, and pump power dependence analyses.