Broadband photoluminescence of Bi2O3–GeO2binary systems: glass, glass-ceramics and crystals

Ultra-broadband emission covering 1000?1800 and 1800?3020?nm of Bi2O3?GeO2 binary system materials, from glass to glass-ceramics to crystals, is presented in this paper. This is the first time, to our best knowledge, that broadband photoluminescence of BGO crystals (including Bi4Ge3O12 and Bi12GeO20) in the range of 1800?3020?nm has been realized. HRTEM, XPS and XANES have been used to investigate the effects of the valence states and the structure environment of bismuth on the emission properties of Bi2O3?GeO2 binary system materials. Bi2+ and Bi+ are proposed as the emission centers of the photoluminescence peaks at 1060 and 1300?nm, respectively. The broadband emission from 1800 to 3020?nm originates from bismuth clusters. Bi2O3?GeO2 binary system materials could be promising laser materials in the field of full-band optical fiber communication amplifiers, ultra-fast lasers and diode pumped solid state lasers, due to their broadband emission spectra and their feasibility of synthesis and drawing into fibers.