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Emission from a bismuth doped chalcogenide glass spanning from 1 μm to 2.7 μm

In this paper we report emission from Bi doped gallium lanthanum sulphide (Bi:GLS) glass with a full width at half maximum (FWHM) of 600 nm which is flattened and covers the entire telecommunications window. The excitation wavelength of this emission was 1020 nm, the quantum efficiency (QE) was 17%, the lifetime was 160 μs and product of the emission cross section and lifetime (σemτ) was 2×10-25 cm2s. The maximum room temperature QE was 32% at 900 nm excitation. At cryogenic temperatures the FWHM reached 850 nm with 974 nm excitation and we observed two new bismuth emission bands at 2000 and 2600 nm. The QE reached 40% for both 974 and 808 nm excitation at cryogenic temperatures. Emission spectra, normalized to the excitation power, taken with excitation wavelengths of 480-1300 nm, revealed 4 absorption bands at 680, 850, 1020 and 1180 nm. The 1180 nm absorption band was previously unobserved. Deconvolution of the emission spectra into Gaussians indicated 5 distinct emission bands over the entire excitation range. The maximum room and cryogenic temperature lifetimes were 175 and 280 μs, respectively. Their respective emission and excitation wavelengths were ~1500 and 974 nm; and ~1600 and 808 nm. By examining previously published models of Bi emission in glasses to see if they could account for the 2000 and 2600 nm emission bands, and reviewing other previously published evidence, we propose that the origin of the emission in Bi:GLS is Bi2 (2-) dimers.