Intense 1.54 μm fluorescence of Er~(3+)/Yb~(3+) codoped phosphate glass and the three-photon phenomenon of near infrared upconversion luminescence

摘要

Transparent P_2O_5-CaO-Na_2O glasses codoped with Er~(3+) and Yb~(3+) 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 μm band, the calculated peak emission cross sections is 1.04×10~(-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 ~4S_(3/2)→~4I_(13/2), which enhances the population of the upper level for 1.54 μm laser emission and reduces the energy loss due to upconversion. Efficient near infrared fluorescence indicates Er~(3+)/Yb~(3+) codoped phosphate glass is a promising laser and amplifier material.