Static Properties of Chiral Nematics

The helical axis z and 0 are arbitrary unless the director is aligned preferentially at 

In the preceding discussion chirality was used only to differentiate between right-handed and left-handed structures, that is, structures in which their mirror images can- 

As described earlier, the spectacular optical properties of chiral nematics are determined by the helicoidal pitch, the birefringence (and refractive index), the direction and polarization of the incident light, and the arrangement of the helix axis. For normally incident light the direction of the helix axis gives rise to the three classical textures depicted in Fig. 2, and typical photomicrographs taken with crossed polarizers are shown in Fig. 6 these are  

The different optical textures induced by the different surface alignment conditions lead us to three common methods of measuring the helical pitch  

Planar texture Using planar alignment and by measuring the reflection or transmission spectrum of a chiral nematic 

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