Upconversion and fluorescence spectral studies of Er 3+/Yb 3+-codoped Bi 2Q 3–GeO 2–Ga 2Q 3–Na 2O glasses

Abstract

The absorption spectra and upconversion fluorescence spectra of Er 3+/Yb 3+-codoped natrium–gallium–germanium–bismuth glasses are measured and investigated. The intense green (533 and 549 nm) and red (672 nm) emission bands were simultaneously observed at room temperature. The quadratic dependence of the green and red emission on excitation power indicates that the two-photon absorption processes occur. The influence of Ga 2C 3 on upconversion intensity is investigated. The intensity of green emissions increases slowly with increasing Ga 2O 3 content, while the intensity of red emission increases significantly. The possible upconversion mechanisms for these glasses have also been discussed. The maximum phonon energy of the glasses determined based on the infrared (IR) spectral analysis is as low as 740 cm −1. The studies indicate that Bi 2O 3–GeO 2–Ga 2O 3–Na 2O glasses may be potential materials for developing upconversion optical devices