Infrared broadband emission of bismuth–thulium co-doped lanthanum–aluminum–silica glasses

The Bi–Tm co-doped SiO2–Al2O3–La2O3 (SAL) glasses, which exhibited a broadband near-infrared (NIR) emission was investigated by the optical absorption and photoluminescence spectra. The super broadband near-infrared emission from 1000 to 2100nm, which covered the whole O, E, S, C and L bands, was observed in the Bi–Tm co-doped samples, as a result of the overlap of the Bi-related emission band (centered at 1270nm) and the emission from Tm3+3H4→3F4 transition (1440nm) as well as Tm3+3F4→3H6 transition (1800nm). Relative luminescence intensity at 1270, 1440 and 1800nm wavelength varied depending on the mixing ratio of Bi and Tm and the full-width at half-maximum (FWHM) extending from 1000 to 1600nm could be 400nm. These results indicated that Bi–Tm co-doped SiO2–Al2O3–La2O3 glasses could provide potential applications in tunable lasers as well as the broadband optical amplifiers in WDM system. ► The fluorescence of Bi–Tm co-doped SiO2–Al2O3–La2O3 glasses were investigated under 808nm excitation. ► A NIR broadband luminescence with a full-width at half-maximum (FWHM) of 400nm from 1000 to 1600nm was observed. ► The mechanism of energy transfer between Bi+ and Tm3+ was presented. ► This material provides potential applications in the broadband optical amplifiers in WDM system.