Interrelationship of Micro- and Macrostructure with Nonlinear Optical Properties of Simple and Binary Acentric Niobate Crystals

Abstract

On the plane of oxide bond lengths the rosette with three ellipses of acentricity have been displayed for noncentrosymmetric (NCS) niobate crystals distributed over 2 groups of paraelastic and ferroelastic crystals. Two small ellipses have perpendicular main axes and main axis of one large ellipse lie on bisector of other ellipses axis. Six characteristic regions and 12 sub-regions are found inside the ellipse rosette showing different crystal structure and χ⁽²⁾ levels: 1) total crossing part of three ellipses; (2) four parts of two small ellipses outside crossing part, 3) one part of large ellipse outside other ellipses. The dependence of nonlinear optical susceptibility χ⁽²⁾ on the shortest niobate bond length Nb‒O has been revealed.

Keywords:

• Structure
• property
• relationship
• niobate crystals