Host dependent frequency upconversion of Er3+/Yb3+-codoped bismuth–germanate glasses

The absorption and upconversion fluorescence spectra of a series of Er3+/Yb3+-codoped xBi2O3–(90 − x)GeO2–10Na2O (BGN x, x = 31, 36, 41, 46 and 51 mol%) glasses have been studied. Intense green and red emission bands at around 533, 548 and 659 nm, corresponding to the 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3+, respectively, were simultaneously observed at room temperature. The dependence of intensities of upconversion emission on excitation power and possible upconversion mechanisms were evaluated and analyzed. The important role of Bi2O3 in upconversion intensity is observed and its influence on the green (533 and 548 nm) and red (659 nm) emissions is compared and dicussed. The influence of Bi2O3 on the upconversion emissions has been investigated based on the IR spectra.