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Cholesteric liquid crystals have received considerable attention for using in various optical devices during recent years.This presentation will demonstrates both optically and electrically switchable tristable optical switches.First is based on the light-matter interactions of dichroic dyes,azo-chiral and liquid crystal.The photo-induced isomerization of the azochiral dopant can alter the thickness/pitch ratio of liquid crystal film and enable the homeotropically aligned device to exhibit three stable fingerprint,focal conic,and homeotropic textures.Second is an electrically activated bistable light shutter that exploits polymer-stabilized cholesteric liquid crystal film.Under double-sided three-terminal electrode driving,the device can be bistable,switched between focal conic and homeotropic textures with a uniform in-plane and vertical electrical field.The dichroic dyes in various textures have different absorptive properties.Multistable attenuation,scattering,and transparent states can be achieved using the dye doped fingerprint,focal conic,and homeotropic textures,respectively.Such a multi-stable optical switch/light shutter exhibits easy switching,a desirable contrast ratio,and low power consumption.It therefore exhibits the potential to be utilized in practical portable information systems and preserve privacy,control illumination and the flow of energy.