The Importance of Being Inhomogeneous: Simulation Approaches for Liquid Crystal Optical Metasurfaces in the Visible

Optical metasurfaces—planar nanostructured devices which can arbitrarily tailor the wavefront of light—may be reconfigured by changing their dielectric environment. The application of external fields to liquid crystals is a particularly promising means by which to tune the optical properties of otherwise static metasurfaces. However, despite recent advances, there is still much progress to be made towards this goal. An outstanding issue is the behavior of liquid crystals adjacent to the nanoparticle “meta-atoms”. The optics of the device depend sensitively on this behavior, especially as the wavelength of operation approaches the visible and, therefore, the length scale of distortions in the liquid crystal director field. Here, we will demonstrate—through combined simulations and experiments—that it is not only the anisotropy of the liquid crystal which is important, but also its spatial inhomogeneity, if one wishes to accurately describe, and therefore predict, the optical properties of liquid crystal metasurfaces.