Circular Intensity Differential Scattering Measurements of Planar and Focal Conic Orientations of Cholesteric Liquid Crystals
We have applied the recently developed technique of circular intensity differential scattering (CIDS) to the study of oriented liquid crystals. The chirality of the liquid crystals and the ease of manipulation of their helical parameters make them an ideal system for investigating the dependence of the CIDS pattern on handedness and pitch. We have studied both right- and left-handed liquid crystals of pitch from 460 nm to 4 microns, with the helix axis oriented either parallel (planar orientation) or perpendicular (focal conic orientation) to the incident beam. The results showed that CIDS is sensitive to the handedness of the helix, for when two liquid crystals of the same pitch but opposite handedness were compared, the signs of their respective CIDS patterns were reversed.
Difficulties encountered in performing these experiments are discussed. The comparison of the results with a theoretical model that uses the second Born approximation shows good agreement.
KeywordsLiquid Crystal Born Approximation Planar Orientation Quartz Plate Stray Light
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