Temperature-dependence on the lifetime of Nd3+-doped phosphate glass

Abstract

The temperature dependence of the photoluminescence spectra and the lifetime of a phosphate glass (P2O5–Al2O3–Na2O–K2O) doped with different concentrations of Nd3+ ions was studied. The emission intensities of the (2S3/2, 4F7/2), (2H9/2,4F5/2),4F3/2 → 4I9/2 transitions were measured in a wide range of temperature from 80 up to 480 K. The changes in the emission band profiles were calibrated by means of the fluorescence intensity ratio method, and the results showed a small dependence on the Nd3+ ions concentration. Moreover, the 4F3/2 state lifetime shows a dependence on the Nd3+ ions concentration and temperature. The concentration quenching, Q, and the lifetime in the limit of zero concentration, τ0, were obtained as a function of temperature. In the limit of zero concentration, where the cross-relaxation process is negligible, the τ0 still showed a dependence on the temperature, where from 80 up to 200 K a thermal quenching occurs. For higher temperatures, its value keeps nearly constant at ~370 μs, in agreement with that previously found by Judd-Ofelt theory. This thermal quenching process is assigned to the population distribution between the two stark levels of the 4F3/2 state, presenting an energy difference of 77 cm−1, in accordance with the other Nd-doped materials.