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Abstract: We report on the effect of various alkaline-earth metal oxides on the broadband infrared luminescence covering 1000–1600 nm wavelength region from bismuth-doped silicate glasses. The full width at half maximum (FWHM) of the infrared luminescence and the fluorescent lifetime is more than 200 nm and 400 μs, respectively. The fluorescent intensity decreases with increasing basicity of host glasses. Besides the broadband infrared luminescence, luminescence centered at 640 nm was also observed, which should be ascribed to Bi2+ rather than to the familiar Bi3+. We suggest that the infrared luminescence should be assigned to the transition of BiO molecules dispersed in the host glasses. [Copyright &y& Elsevier]

Abstract: Bi-doped and Yb–Bi-codoped SiO2–Al2O3–CaO glasses were prepared, and the effect of Al2O3 composition on the near-infrared (NIR) emission and energy transfer between Yb3+ and Bin+ (Bi NIR emission centers) were investigated. The introduction of Al2O3 into the glass hosts can vary the NIR luminescence centered at 1300nm and obtain the strongest emission when the concentration of Al2O3 is 15mol%. Efficient energy transfer from Yb3+ to Bin+ is achieved by co-doping of Al2O3. With the increased Al2O3 concentration, the energy transfer efficiency between Yb3+ and Bin+ increased at first and then decreased, maximizing (~79%) at 8mol%. It is suggested that the introduction of appropriate Al2O3 concentration in Yb–Bi-codoped silicate glasses may be an efficient way to realize effective optical amplification with commercially available 976nm LD pumping. [Copyright &y& Elsevier]