Negative dispersion of birefringence in two-dimensionally self-organized smectic liquid crystal and monomer thin film

We suggest a method to obtain a negative dispersion (ND) of birefringence using a two-dimensional self-organization of smectic liquid crystal (LC) and monomer molecules. The averaged orientation of the smectic LC was the layer normal direction with the extraordinary refractive index n_e. Meanwhile, the orientation of the monomer molecules was templated by the host-smectic LC and parallel to the layer plane corresponding to the ordinary refractive index n_o. We selected the LC molecules absorbing a shorter wavelength of UV light rather than the polymerized monomers, hence n _e was more smoothly decreased than n_o in the visible-wavelength range. Consequently, the birefringence Δ_n ≡ n_e - n_o was increased with a longer wavelength, thus giving a ND of birefringence. Using the proposed method, the ND of birefringence could be obtained in a single layer, which is desirable for thin flexible applications.