Investigation of mid-infrared emission characteristics and energy transfer dynamics in Er3+ doped oxyfluoride tellurite glass

Er3+ doped oxyfluoride tellurite glasses have been prepared. Three Judd-Ofelt parameters Omega(t) (t = 2, 4, 6) and radiative properties are calculated for prepared glasses. Emission characteristics are analyzed and it is found that prepared glasses possess larger calculated predicted spontaneous transition probability (39.97 s(-1)), emission cross section sigma(em) (10.18 x 10(-21) cm(2)) and sigma(em) x Delta lambda(eff) (945.32 x 10(-28) cm(3)), corresponding to the 2.7 mu m emission of Er3+: I-4(11/2) -> I-4(13/2) transition. The results suggest that the prepared glasses might be appropriate optical material for mid-infrared laser application. Moreover, rate equation analysis which is rarely used in bulk glass has been carried out to explain the relationship between emission intensity and Er3+ concentration. The calculation results show that with the increment of Er3+ concentration, the energy transfer up-conversion rate of I-4(13/2) state increases while the rate of I-4(11/2) state reduces, resulting in the change of 2.7 mu m emission.