Nematic liquid crystal film with a nonlinear index coefficient of over 10 cm/sup 2//watt and ms response speed

We have previously reported the observation of an extremely nonlinear optical effect in aligned methyl-red doped nematic liquid crystal [NLC] film, associated with optically induced liquid crystal director axis reorientation. Unlike the so-called photorefractive effect in other dye or C 60 doped film, no dc bias voltage is required. The response times are on the order of milliseconds, depending on the optical intensity and film geometry. The effect has been demonstrated in both planar and homeotropic aligned films. The effect can be enhanced by an ac field of appropriate frequency applied along the director axis in a homeotropically aligned NLC film.