Influence of Yb³⁺/Ho³⁺ codoping on optical and thermal properties of TeO₂-ZnO glass

Abstract

This paper reports the effect of incorporation of Yb3+ ions on the frequency downconversion luminescence and thermal properties of triply ionised Ho3+ doped zinc tellurite (TZ) glasses. The photoluminescence spectra of both the Ho3+/Yb3+ doped and codoped glasses have been recorded and observed a green emission band corresponding to the 5F4, 5S2→5I8 (~550 nm) transition upon various excitations. In the downconversion (DC) emission process, the back energy transfer (BET) mechanism from Ho3+ ions to Yb3+ ions has also been explored. The colour emitted in the downconversion process is found to be non-tunable at different excitations. Thus, the Ho3+:TZ glass can be utilised for non-colour tunable optical devices under various UV excitations. Also the glass transition (Tg) and crystallisation (Tc) temperatures have been measured for both the doped and codoped glasses and found to be increased in the codoped glass. The singly Ho3+ions doped TZ glass shows better optical downconversion and glass forming ability.