Optical thermometry and broad infrared luminescence in highly sensitized TBO glass

Abstract

This work mainly reports the optical thermometry based on frequency upconversion and the infrared luminescence of Er3+-Yb3+ codoped TeO2-B2O3 (TBO) glasses prepared via melt-quenching technique. The amorphous nature of the prepared glass samples has been confirmed from the XRD analysis. FTIR analysis of the prepared glasses shows the existence of possible bands along with the phonon energy ∼670 cm−1. Judd-Ofelt analysis has been performed on the basis of absorption spectra and various radiative parameters calculated. The order of the intensity parameters (Ω6 > Ω2 > Ω4) indicates ionic nature of the Er-O bond which is further confirmed by the naphelauxetic ratio, covalency and bonding parameter. The enhancement of about 155 times and 327 times in the green and red UC emission intensity of the codoped glass as compared to the Er3+ doped TBO glass has been reported. The absorption cross-section around 980 nm in the codoped glass is found to be ∼43 times larger as compared to the 4I15/2 → 4I11/2 absorption transition in the Er3+ doped glass. The temperature sensing study of the codoped glass with high ‘Ω6’ value has been performed and low value of the absolute sensitivity has been explained on the basis of Judd-Ofelt parameters. The figure of merit for gain bandwidth (9216.81 × 10−27 cm3) & maximum gain coefficient (2.27 cm−1) corresponding to the infrared luminescence peaking at ∼1.5 μm and spectroscopic quality factor (0.28) have been evaluated.