Electrically controlled transparency of salted liquid crystal

We propose a new composite system consisted of micro-crystals of alkali halides dispersed in nematic liquid crystal (LC). We studied NaCl-particles dispersed in pentyl-cyanobiphenyl (5CB). LC doping with NaCl-particles does not change the macroscopic properties of LC. Strong interaction between LC molecules and the surface of the microcrystals results in a strong light scattering by the suspension. Application of an electric field switches the material to a light transparent state due to director reorientation and matching of the refractive indexes of the LC domains and micro-crystals. The initial state recovers very quickly (< 1 ms) at field removing. We consider alkali halide suspensions very promising for IR applications since they are highly transparent in this spectral region.