Using4×4Matrix Optics Method For Defective Layer Of Thin Layer Of Cholesteric

Periodic helical structure of cholesteric liquid crystal makes its produce selectivityreflection to specific wavelengths of light, forms energy gap on the frequency spectrum andhas the characteristics of photonic crystals. When introducing defects in the cholestericliquid crystal there will be a defect mode on the reflection spectrum, that has considerableapplication on many areas now.This paper introduces defects on the basis of cholesteric liquid crystal. The types ofdefects include: doped defect, twist defect, gradient jump defect, pitch jump defect.Especially, an in-depth and detail study of adding two layers of isotropic medium or theanisotropic medium to the cholesteric liquid crystal. In view of the different variables,including: the thickness of liquid crystal box, the thickness of doping medium, the numberof dielectric layer, the location of the dielectric layer, the refractive index of the medium,the refractive index change rate of the medium, the size of the distortion angle, the changerate of pitch gradient of pitch gradient structure and so on, study the change of the defectmodes. Using Berreman4×4matrix deriveds the specific expression of doping medium, andcalculates the transmittance and reflectance. At the same time using matlab simulatleft-hand and right-handed circularly polarized light’s reflection spectrum.Introduced the defects in the cholesteric liquid crystal, making the reflection spectrumof defect on film, and reflection bandwidth will change too. The introduction of thedifferent defects makes the number of defect modes, the location, the defects correspondingreflectivity, reflection bandwidth will be different. The change of the different variablesmakes the reflection spectrum and the defects produced is not the same. So we canaccording to the different of equipment required, choosing a different defect type, orintroducing one or more defects at the same time.