Influence of dopant concentration on the structural and optical characteristics in Ti doped (2 and 5 mol%) LiNbO 3 nonlinear optical single crystal

Abstract

Congruent lithium niobate single crystal with titanium ion dopant (2 and 5 mol%) has been successfully grown in an air by Czochralski technique with Automatic Diameter Control facility. The results of analysis of the influence of the Ti dopant concentration on X-ray diffraction, refractive index, optical absorption edge and FTIR in lithium niobate single crystals were presented. High Resolution X-ray Diffraction technique was used to study the crystalline quality through full width half maximum values with the presence of dopant incorporation. The increase of refractive index values observed for doped samples than pure sample by prism coupling technique with different laser sources. The position of the fundamental absorption edge in the near UV region was analyzed by UV–Vis spectra. FTIR spectra revealed that 5 mol% Ti doped lithium niobate crystals clearly suppresses the OH − defect sites than 2 mol% which indicates the limited influence of the humidity. The reason for OH − defect site suppression is discussed. Also the obtained results from all measurements are compared with pure congruent lithium niobate crystal.