The effect of lyotropic liquid crystalline material, below Krafft temperature, in changing the polarization of the optical beam has been demonstrated. It is found that the lamella structures formed in the material below Krafft temperature are birefringent and this birefringence can be controlled by flowing it in rectangular channel under a suitable flow rate.

This paper illustrates the conoscopic observation of a molecular reconstruction occurring across a nematic liquid crystal (NLC) medium in the presence of an external electric field. Conoscopy is an optical interferometric method, employed to determine the orientation of an optic axis in uniaxial crystals. Here a planar aligned NLC medium is used, and the topological changes with respect to various applied voltages are monitored simultaneously. Homogenous planar alignment is obtained by providing suitable surface treatments to the ITO coated cell walls. The variation in the conoscopic interferometric patterns clearly demonstrates the transition from planar to homeotropic state through various intermediate states.

The propagation of laser beam in a flow aligned nematic liquid crystal (NLC) and its interaction with liquid are illustrated in this letter. The effect of polarization and scattering on the transmitted power through the NLC under external perturbation flow is demonstrated here. It is found that the flow rate has a significant role in the modulation of refractive index of the medium leading to scattering and change in polarization. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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