Near infrared luminescence properties and mechanism of high bismuth-doped SiO2-Al2O3-La2O3 glass

Abstract

This research investigated the wideband near-infrared spectroscopy characteristics of 60SiO2-25Al2O3-10La2O3 glass doped with high levels of bismuth up to 5 mol%. The near-infrared radiation range was explored under excitation wavelengths of 488 nm, 532 nm, 808 nm, and 980 nm, resulting in near-infrared radiation spanning from 1000 nm to 1800nm with Full Width at Half Maximum (FWHM) values of 313.0 nm, 336.3 nm, 296.2 nm, and 262.9 nm, respectively. Notably, the sample exhibited a lifetime of 1.473 ms when pumped at 808 nm, corresponding to a stimulated cross-section of σe=3.35 × 10−21 cm2. Through an in-depth investigation of the luminescence properties, the underlying physical mechanism behind the near-infrared luminescence was revealed. The emissions observed at approximately 1150 nm and 1300 nm were attributed to the aluminum-related bismuth active center (BAC-Al) and the silicon-related bismuth active center (BAC-Si), respectively. Furthermore, it is postulated that the emission at the 1150 nm band originates from the 3P1, 3P2 →3P0 transition of Bi+ and the 2D3/2 → 4S3/2 transition of Bi°, while the emission at the 1300 nm band may be linked to mixed valence states of Bi3+. This work will find potential applications in broadband near-infrared optical devices.