Intense 1.54 Mu M Fluorescence Of Er3+/Yb3+ Codoped Phosphate Glass And The Three-Photon Phenomenon Of Near Infrared Upconversion Luminescence

Transparent P2O5-CaO-Na2O glasses codoped with Er3+ and Yb3+ ions were fabricated by high-temperature melting technique. Strong near infrared and visible upconversion luminescence were observed under 975 nm laser diode excitation, and the luminescence processes were explained in details. For 1.54 mu m band, the calculated peak emission cross sections is 1.04x10(-20) cm(2), and it is better than that in germinate, tellurite, silicate, and other phosphate glasses. The near infrared upconversion emission around 828 nm contains two-photon and three-photon processes, and it is attributed to the transition S-4(3/2)-> I-4(13/2), which enhances the population of the upper level for 1.54 mu m laser emission and reduces the energy loss due to upconversion. Efficient near infrared fluorescence indicates Er3+/Yb3+ codoped phosphate glass is a promising laser and amplifier material.