Metamaterials: Nano-dispersed liquid crystal with tunable negative-zero-positive refractive indices

The nematic liquid crystals (LC) containing core-shell nano-spheres can form a new type of metamaterial whose index of refraction is tunable from negative through zero to positive values. The core-shell nano-spheres can be made of polaritronic or semiconductor materials, and the liquid crystal can be in any of the nematic, ferroelectric or cholesteric phases. The combination of permittivities of non-magnetic materials at the appropriate resonances, in conjunction with the field-induced permittivity change in the LC host, give rise to the effective refractive index. The real part of effective refractive index of the nano-spheres dispersed liquid crystal (NDLC) for core and shell parameters can be computed using the Maxwell Garnet mixing rule. These reconfigurable materials can be very useful for designing tunable flat lenses operating in the optical domain.