Optical absorption and OH- transmission spectra in Mg : Er : LiNbO3 crystals

摘要

Mg:Er:LiNbO3 crystals were grown by the Czochralski method. Their UV-Vis absorption edges and OH- transmission spectra were measured in terms of the defect structure. The absorption edges shift towards a shorter wavelength with increasing Mg concentration. The dependence of the shift mechanism of the absorption edge on the defect structure was discussed in detail. The OH- absorption bands shift from 3486 cm(-1) to 3535 cm(-1) when the Mg concentration exceeds a threshold value. It is considered that the 3535 cm(-1) absorption band corresponds to the (MgNb)(3-)-OH- complexes.