飞秒激光诱导的Mn 2+ 掺杂锗酸盐玻璃上转换发光

The upconversion luminescence of Mn2 +doped transparent germanate glass induced by800 nm femtosecond laser at room temperature was investigated. The excitation and emission spectra show that the excitation process stems from the6A(6S) →4E(4G) /4A1(4G) transition while the emission originates from the4T1(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.