Photoluminescence and Features of the Defective Structure of Nominally Pure Lithium Niobate Crystals

Abstract

The photoluminescence intensity in lithium niobate crystals close to the stoichiometric composition is lower than in a congruent crystal was established. An increase in the Li / Nb ratio leads to a shift in the photoluminescence bands to the short-wavelength region of the spectrum and a change in the fundamental absorption edge of the crystals under study. It was shown that, in addition to point defects in the cationic sublattice, complex defects due to the presence of OH groups in the structure can also contribute to photoluminescence.