Properties of Up-conversion Emission of Er~(3+)-doped Silicate Glasses

Absorption spectra and up-conversion emission spectra of Er3+-doped silicate glasses were investigated. The intensity parametersΩλ(λ=2,4,6), the oscillator strength, the spontaneous transition probabilities and the fluorescence branching ratios were calculated by the theory of Judd-Ofelt. The up-conversion emission spectra show there are stronger green light and red light centered about 522nm, 545nm and 658nm, corresponding to the transition of 2H11/2→4I15/2,4S3/2→4I15/2,4F9/2→4I15/2, and the slope of fitted lines is 1.76, 1.94, 1.67, respectively, which indicates a two-photon process for the green and red light. The up-conversion mechanisms are determined to be excited state absorption and energy transfer.