Energy transfer between Tm3+ and Er3+ ions in a TeO2-based glass pumped at diode laser wavelength

Abstract In this paper we investigate the energy transfer processes in Tm 3+ /Er 3+ doped telluride glass pumped at the commercial diode laser pump wavelength ∼800 nm. Tailoring the rare-earths content in the glass matrix, seven main energy transfer channels within the doping range considered were identified. A 6-fold enhancement of the Er 3+ visible frequency upconversion fluorescence at ∼660 nm is observed due to the inclusion of Tm 3+ ions. This is evidence of the relevant contribution of the route Er 1 ( 4 I 11/2 ) + Er 2 ( 4 I 13/2 ) → Er 1 ( 4 I 15/2 ) + Er 2 ( 4 F 9/2 ) to the process. Energy migration among pumped 4 I 9/2 level reducing the efficiency of the upconversion emission rate ( 3 H 11/2 , 4 S 3/2 , and 4 F 9/2 ) is observed for Er 3+ above 1.5 wt%. The rate equations regarding the observed energy transfer routes are determined and a qualitative analysis of the observed processes is reported.