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

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 the⁵F₄,⁵S₂→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 (T_g) and crystallisation (T_c) 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.