Memory chiral nematics

On removal of the low frequency field, in thick cells, the texture relaxes back to focal conic with residual light-scattering properties. This has been described as the storage mode or memory effect in chiral nematic systems [162]. If a high frequency ac field is now applied (o)> co ), the dielectric torque restores the nonscattering planar texture and, just as in smectic A materials, this effect can be used in electrooptic storage mode devices [165], since we have a low frequency write and high frequency erase mechanism. 

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