Liquid crystals Liquid crystals are a phase of matter whose order is intermediate between that of a liquid and that of a crystal. The molecules are typically rod shaped organic moieties about 25 Angstroms in length and their ordering is a function of temperature. The nematic phase for example is characterized by the orientational order of the constituent molecules. The molecular orientation (and hence the materials optical properties) can be controlled with applied electric fields. Liquid crystal science and applications permeate many segments of society from large industrial displays to individual homes and offices. Non display applications in nonlinear optics optical communication and data signal image are receiving increasing attention and are growing at a rapid pace