研究了室温下的飞秒激光诱导过渡金属Mn2+ 掺杂锗酸盐玻璃的上转换发光现象。样品的激发光谱与发射光谱表明, 激发过程是能级6A(6S)→4E(4G)/4A1(4G)的跃迁, 该过程源于Mn2+离子的4T1(4G) → 6A1(6S)跃迁。由409 nm单色光激发样品得到的发射光谱与800 nm飞秒激光激发的光谱相一致。通过分析飞秒激光泵浦功率密度与荧光强度的依赖关系以及飞秒激光辐照样品前后的吸收谱, 认为该上转换过程为双光子同时吸收过程。随着Mn2+浓度的提高, 上转换发光的中心波长发生红移。

The upconversion luminescence of Mn2+ doped transparent germanate glass induced by 800 nm femtosecond laser at room temperature was investigated. The excitation and emission spectra show that the excitation process stems from the 6A(6S)→4E(4G) / 4A1(4G) transition while the emission originates from the 4T1(4G)→6A1(6S) transition of Mn2+ . The emission spectrum excited by 409 nm monochromatic light is similar to that irradiated by 800 nm femtosecond laser. Moreover, by measuring the dependence of the fluorescence intensity on the pump power together with the absorption spectra of both the undoped and doped glass, the conversion of infrared radiation to the visible emission dominated by a two-photon absorption process is confirmed. As Mn2+ is the only emission center, a significant red-shift with the increasing of Mn2+ concentration is also observed.