Enhanced 1.8 μm emission in Er3+/Tm3+ co-doped lead silicate glasses under different excitations for near infrared laser

A detailed study of the fluorescence emission properties and energy transfer mechanism in Er3+/Tm3+ co-doped lead silicate glasses was reported. Enhanced near infrared 1.8 mu m and visible up-conversion emissions were investigated under 808 and 980 nm excitations, respectively. The energy transfer mechanism between Er3+ and Tm3+ was analyzed according to the absorption spectra, the emission spectra and the level structures of Er3+ and Tm3+. The energy transfer efficiency between Er3+ and Tm3+ reached 68.1% in the Er3+/Tm3+ co-doped lead silicate glasses when pumped by 808 nm laser diode. Based on the absorption spectra, the Judd-Ofelt parameters, spontaneous emission probability, absorption and emission cross sections, gain coefficients were calculated and analyzed. It was found that the calculated emission cross section and the maximum gain coefficient around 1.8 mu m were 4.9x10(-21) cm(2) and 1.12 cm(-1), respectively. These results indicated that the Er3+/Tm3+ co-doped lead-silicate glasses had potential application in near infrared lasers.