Light Diffraction and Light Scattering in Nematic Liquid Crystals with a Positive Dielectric Anisotropy

A light diffraction pattern is observed in nematic liquid crystals with a positive dielectric anisotropy and is found to agree with that of a grating consisting of periodic slits spaced at nearly equal intervals. The sequence of diffraction spots extends along a direction perpendicular to the rubbing direction of the glass electrode surfaces. At a higher electric field, the characteristic light scattering pattern is observed, the shape of which is the well-known four-leaf-clover with a weak scattered light intensity indicating the existence of domains with a shape similar to that of polymer spherulites.