Time-resolved fluorescence line narrowing spectroscopy and fluorescence quenching in Nd3+-doped fluoroarsenate glasses

Abstract The spectral migration of energy among the Nd 3+ ions in fluoroarsenate glasses of the Na 4 As 2 O 7 , BaF 2 , YF 3 system with different Nd 3+ concentrations (0.5, 2, 3, 4, and 5 mol%) has been investigated by using time-resolved fluorescence line narrowing (TRFLN) spectroscopy. The features of the time-resolved fluorescence line narrowing 4 F 3/2  →  4 I 9/2 emission spectra obtained under resonant excitation at different wavelengths along the 4 I 9/2  →  4 F 3/2 transition as a function of Nd 3+ concentration reveal the existence of energy migration between discrete regions of the inhomogeneously broadened spectral profile. The analysis of the time evolution of the 4 F 3/2  →  4 I 9/2 narrowed emission shows that the electronic mechanism responsible for the ion–ion interaction can be identified as a dipole–dipole energy transfer process. From the thermal behavior of lifetimes of the 4 F 3/2 state a T 3 dependence for the non-radiative Nd–Nd relaxation processes has been found in the 10–80 K temperature range for Nd 3+ concentrations higher than 0.5 mol% which is in agreement with a two-site non-resonant process.