Search

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]

Abstract: In 1.30BaO·6Al2O3:Eu and 0.82BaO·6Al2O3:Eu with β′- or β-alumina structure respectively, prepared in air, the doped Eu3+ ions were partially reduced to Eu2+ ions. X-ray powder diffraction patterns and photoluminescent spectra were employed to characterize the compound structures and to detect the existence of Eu2+ ions, respectively. The reduction mechanism of Eu3+→Eu2+ was proposed to be due to the existence of negative defects (e.g. ) in these compounds. This is the first observation of the reduction of Eu3+→Eu2+ in non-stoichiometric compounds prepared in an oxidizing atmosphere. And the luminescent properties of Eu2+ in the compounds of xBaO·6Al2O3:Eu2+ (x=0.82, 1.00, 1.30) showed similar behavior due to their similarity in crystal structures. [Copyright &y& Elsevier]

Abstract: We have studied the effects of Si doping on the near infrared (NIR) luminescence observed in low Bi doped ( 0.1mol% ) glasses and the energy transfer from Yb3+ to Bi. The broadband near infrared can only be observed when Si is introduced in the Bi-doped glass. The origin of this fluorescence can be attributed to Bi ions at low valence. Efficient energy transfer from Yb3+ to Bi NIR active ions is achieved by co-doping of Si. There is an increment of about ~29 times of the emission intensity from Bi-related active center as the Yb3+ concentration varies from 0 to 2.0mol% and the amount of Si is 0.05mol% under 980nm excitation. The possible mechanism of energy transfer from Yb3+ to Bi is also discussed. [Copyright &y& Elsevier]

Abstract: Porous glass with high-SiO2 content was impregnated with Nd ions, and subsequently sintered at 1100°C into a compact non-porous glass in air or reducing atmosphere. Sintering in a reducing atmosphere produced an intense violet–blue fluorescence at 394nm. However, the sintering atmospheres almost did not affect the fluorescence properties in the infrared range. A good performance Nd3+-doped silica microchip laser operating at 1064nm was demonstrated. The Nd-doped sintering glasses with high-SiO2 content are potential host materials for high power solid-state lasers and new transparent fluorescence materials. [Copyright &y& Elsevier]