Effect of SiO2 on optical properties of bismuth-doped B2O3–GeO2–SiO2 glasses

Abstract

Bi-doped (60-x)GeO2–xSiO2–15B2O3–20MgO–5Al2O3–0.5Bi2O3 (x = 0, 5, 10, 15,20, 25 mol%)glasses were prepared by a conventional melt-quenching process. A broad near-infrared (NIR) photoluminescence (PL) band from Bi centers centered around 1100 nm with a large full-width-at-half-maximum value (~ 195 nm) was observed under excitation at 700 nm. Along with the increase of SiO2 concentration, the NIR PL intensity and the quantum yield (44.1–51.2%) increase first and then decrease, and the PL lifetime increases from 409 to 464 µs. The spectroscopic properties can be interpreted in terms of Bi centers with different valence states, which were confirmed by two-dimension photoluminescence excitation map spectra. The dependence of optical properties on SiO2 concentration is mainly attributed to the change of the optical basicity among different samples. This Bi-doped B2O3–GeO2–SiO2 glass could find potential application in fiber amplifier and laser due to the efficient and tunable broad NIR luminescence.