Mauguin condition

When the Mauguin condition is violated, it is much nore difficult to describe the lightwave-cholesteric interac-ion because the natural models of the LC are elliptically po-arized waves whose properties depend in a complicated way >n the angle of incidence of the wave and on the ratio of the wavelength divided by the pitch of the helices. However, this >roblem can be solved without difficulty by using the results n Ref 11. 

The use of a single polarizer or analyser is sufficient to vary the defect contrast considerably. As the local ellipsoid of indices is positively uniaxial and the twist is weak, the electric vector of any penetrating wave rotates as the director orientation (Mauguin s condition the wavelength being very small compared to the cholesteric pitch) [66, 67]. 

---