Annihilation of the OH absorption due to domain inversion in MgO-doped lithium niobate crystals

摘要

The influence of domain inversion on the infrared absorption of lithium niobate crystals with varying MgO doping is investigated. The authors observe a significant difference between crystals doped below and those doped above the so-called optical damage threshold. The shift of the OH absorption due to domain inversion for weakly doped or undoped samples, known from the literature, can be confirmed. However, for highly doped samples the peak vanishes completely after forward poling. It reemerges either by reverse poling or by annealing at 250℃. The mechanism is yet not fully understood but has to be correlated with the defect structure of the crystal.