The role of Fe and Cu dopants in electron–hole trapping and relaxation process in congruent LiNbO3

Abstract The transient optical absorption and kinetics of absorption decay is studied in undoped, Fe doped, and Cu doped LiNbO 3 crystals irradiated by pulsed electron beam. The 1.6 eV band of electron polaron trapped at antisite niobium was observed in all crystal samples. The nature of centers responsible for transient absorption is discussed. Electron polarons are shown to be less stable in LiNbO 3 :Fe compared with LiNbO 3 :Cu and undoped LiNbO 3 . It is suggested that a major part of electrons and holes created by irradiation are trapped in the vicinity of dopants.