Liquid crystals tunable optical metamaterials

A critical discussion with detailed calculations for the complex refractive indexes of metamaterials of various nanoconstituent makeups, sizes, shapes and concentrations, and periodic nanostructured patterns/geometry are presented. These metamaterials possess tunable subunity, zero, or negative refractive indexes, on account of the large birefringence of their nematic liquid crystal constituent. We also studied the special case involving laser dye-doped nematic liquid crystals that could provide optical gain. It is shown that the resulting metamaterials loss can be minimized, while achieving the desired tunable birefringence. Some preliminary experimental studies have demonstrated fast optically induced modulation of the nematic liquid crystals and indicated the possibility of ultimately realizing fast tunable or nonlinear optical metamaterials.