Techniques of observation and characterization of the domain structure in periodically poled lithium niobate

The domain structure of bulk periodically poled lithium niobate crystals we re analyzed by different techniques. Images of topography, electrostatic fo rce, and piezoelectric response were studied by scanning force microscopy. All these images showed the domain structure of the samples, The electrosta tic force was always attractive pointing to a dielectric origin. The diffra ction of a laser beam by the periodic structures was also observed, denotin g a periodic change of refractive index. From the angle of diffraction the domain spatial frequency was directly obtained. The topographic profile of etched samples was studied by both scanning force and scanning electron mic roscopy.