On the near-infrared luminescence from TeO2 containing borate glasses

The effects of melting temperature and glass composition on the Near-infrared (NIR) luminescent characteristics of Te-containing borate glasses are investigated and compared with previous works. Three absorption bands are detected at around ~370 nm, ~430 nm and ~530 nm, however, the absorption band at around ~600 nm could not be detected in all borate glasses. And no NIR luminescence was observed under the excitation of a 974 nm laser diode. The NIR luminescence was observed in Te-green and Te-purple glasses, which showed the absorption band at around ~600 nm. This absorption band was ascribed to 2Πg → 2Πu transition of Te2-. Consequently, it is suggested that the origin of NIR luminescence of Te-containing green and purple glass is likely to be caused by Te2- center. (Not to sure of the meaning of this sentence...)