INVESTIGATIONS ON DEFECT STRUCTURE AND LIGHT-INDUCED SCATTERING OF Mg:Ho:LiNbO3 WITH VARIOUS Mg2+ CONCENTRATION

Abstract

Congruent Ho 3+ (1 mol.%): LiNbO 3 crystals codoped with MgO (X mol.%, X = 1, 3, 5 and 7) were grown by the Czochralski technique. The ultraviolet-visible (UV-Vis) and infrared (IR) spectra were measured in order to analyze the defect structure of the crystals. The concentrations of Mg , Ho , Li and Nb in the crystals were carried out with an inductively coupled plasma atomic emission spectrometer. Experimental results indicates as Mg 2+ doping concentration increases in melt, the distribution coefficients of Mg and Ho ions decrease, the Li / Nb ratio in the crystals decreases first and then increases, and the absorption edge shifts to a shorter wavelength. The light-induced scattering of Mg : Ho : LiNbO 3 crystals was quantitatively scaled via the incident exposure energy. The results demonstrated that Mg (7 mol.%): Ho : LiNbO 3 crystal had the weakest light-induced scattering and the mechanism related to their defect structures was discussed.