Optical spectra and luminescence dynamics of Pr³⁺ and Nd³⁺ in SrLaAlO₄ single crystals

Abstract

Single crystals of SrLaAlO₄: Pr³⁺ and SrLaAlO₄: Nd³⁺ have been grown by the Czochralski method and their optical properties have been studied for different activator concentrations. The absorption and emission spectra of the activators are inhomogeneously broadened because the Sr²⁺ and La³⁺ ions are distributed randomly on the sites ofC _4υ symmetry, however, the symmetry selection rules are still obeyed. Strong self-quenching of the praseodymium luminescence occurs by cross relaxation which is supposed to be assisted by phonon emission in the case of the³ P ₀ level. Self-quenching of Nd³⁺ luminescence disappears at low temperature indicating that the condition of resonance in the cross-relaxation process is fulfilled only for higher components of the ground state.