Thermal and optical properties of Bi ions doped GeO2-Al2O3-Na2O glasses

The 96GeO-(3-χ)Al2O3-χNa2O-1NaBiO3 (molar fraction χ is 0,0.5,1.5, designated as A1, A2 and A3, respectively) and 96GeO-(3.5-ψ)Al2O3-ψNa2O-0.5Bi2O3(molar fraction ψ is 0.5,1,2, designated as B1, B2 and B3, respectively) glasses were prepared by conventional melting method. The near infrared superbroadband emission characteristics of the glasses were observed (peak at 1 220 nm) when pumped by an 800nm laser diode. The result indicated that doping of Bi5+ of NaBiO3 could increase the emission intensity of the glass in the infrared band by 4.6 times than that of Bi3+ of Bi2O3. The emission lifetime and the full width at half maximum(FWHM) at 1 220 nm increased from 280 μs, 195 nm to 434 μs, 275 nm, respectively. Meanwhile, the absorption edges of A3, A2, A1 were red-shifted. Thus, it