Anomalous decays in Nd3+ doped LaAlO3 single crystal

Luminescence decays of metastable Nd3+:4F3/2 level were measured and studied in wide of 10-300 K temperature range and compared with the radiative lifetimes derived from standard Judd-Ofelt theory. Nearly resonant cross-relaxation was found to non-radiatively depopulate the metastable level already in 10 K, whereas above 50 K increased reabsorption of radiation and thermalization of higher Stark component of the 4F3/2 level occur, which resulted in the Boltzmann population of this metastable Nd3+ level and anomalous increase of luminescence decays with temperature increment.