Birefringence in Liquid Crystals

Birefringence is an optical property of certain materials in which light rays of different polarizations are subject to different refractive indices 

In hquid crystal materials, birefringence originates from bulk anisotropy. When a nonpolarized monochromatic light ray passes into a liquid crystal medium, it can be resolved into two components with orthogonal polarization directions. As each of these rays will experience a different refractive index, one will travel faster than the other, creating a phase difference between the two. 

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