the first introduction of polymer dispersed liquid crystals using phase separation and the encapsulation methods , now there are many techniques for preparing such composite liquid crystallinematerials, including for example, optical holographic interference methods. These latest PDLC structures possess excellent optical qualities that enable high diffraction efficiency as well as laser emission capabilities.
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3.1
crossThe high scattering cross-sections
Firstly, I will introduce The high scattering cross-sections Light scatterings by dielectric constant changes associated with director axis fluctuations in nematic liquid crystals are many orders of magnitude stronger than all other mechanisms.
the energy provided by the light beam is of the form:
liquid crystal droplets and therefore assume a random distribution .This causes large scattering. however ,when there is an external field, the droplets will be aligned (Fig. 2.10(b)), and the system will become clear, the refractive index of the liquid crystal droplets will be like the isotropic liquid.