Nematic liquid crystal nanocomposite with scattering-free, microsecond electro-optic response

We report a microsecond electro-optic response in an anisotropic-polymer/liquid-crystal composite, which forms a homogeneously mixed structure in the nanoscale range owing to the high miscibility between them. The nanocomposite was fabricated by photopolymerizing a nematic liquid crystal (NLC) mixture doped with a cross-linkable mesogenic monomer at a concentration of 30 wt%. Our system is inherently different from polymer-dispersed liquid crystals in that the LC molecules are almost miscible in the anisotropic polymer matrix and do not form observable domains. When an electric field is applied to such a nanocomposite, the molecular alignment of the polymer matrix is retained, while the non-polymerizable NLC reorients along the electric field, leading to a shift in the birefringence. Furthermore, the reorientation of the NLC molecules in a space sufficiently smaller than the wavelength of visible light results in scattering-free characteristics over the entire visible wavelength range and a short decay response time of 15 mu s. (C) 2014 Optical Society of America