2 μm fluorescence radiative dynamics and energy transfer between Er3+ and Tm3+ ions in silicate glass

A Er3+/Tm3+ co-doped silicate glass with good thermal stability is prepared by melt-quenching method. An efficient emission of ∼2 μm is observed under different selective laser excitations. The optical absorption and transmission spectra, Raman spectra, and emission spectra are tested to characterize ∼2 μm emission properties of Er3+/Tm3+ co-doped silicate glasses and a reasonable energy transfer mechanism of ∼2 μm emission between Er3+ and Tm3+ ions is proposed. Based on the optical absorption spectra, the Judd–Ofelt parameters and radiative properties were calculated. Intense ∼2 μm emission is obtained from Er3+/Tm3+ co-doped silicate glasses due to the efficient energy transfer from Er3+ to Tm3+ ions. The energy transfer coefficient from Er3+ to Tm3+ ions can reach as high as 13.39 × 10−40 cm6/s. In addition, the population of the OH groups is decreased and the ∼2 μm emission is effectively enhanced with fluoride introduction. The emission property, together with good thermal property, indicates that Er3+/Tm3+ co-doped silicate glass is a potential kind of laser glass for efficient ∼2 μm laser.