Energy transfer based efficient infrared emission at 1.57 μm from Yb3+–Er3+ codoped Zinc-borobismuthate glasses

Abstract

An intense NIR emission at 1.57μm is reported in a newly synthesized Yb3+–Er3+ codoped Zinc-borobismuthate glasses. The energy transfer efficiency is found to be 78% for 1mol% Yb2O3 and 0.5mol% Er2O3 concentrations. The transfer process follows a static energy transfer mechanism at a low donor concentration (0.1mol%); whereas, it gets accelerated by donor energy migration at 1mol% Yb2O3. In this glass system, the energy back-transfer has found to be negligible from estimated critical interaction distances for direct (Yb3+→Er3+) and back (Yb3+←Er3+) energy transfer phenomena. The observed efficient NIR emission at 1.57μm has been explained based on the effective energy transfer from Yb3+ ions accompanied by rapid depopulation of 4I11/2 excited level of Er3+ ions through non-radiative multi-phonon relaxation processes, which has also restricted the excited state absorption (ESA) from this level leading to no upconversion suggesting the potentiality of present glass host for proficient NIR luminescence.