Liquid crystal clad near-infrared metamaterials with tunable negative-zero-positive refractive indices

Near-infrared metamaterials that possess a reconfigurable index of refraction from negative through zero to positive values are presented. Reconfigurability is achieved by cladding thin layers of liquid crystal both as a superstrate and a substrate on an established negative-index metamaterial, and adjusting the permittivity of the liquid crystal. Numerical results show that the index of refraction for the proposed structure can be changed over the range from -1 to +1.8 by tuning the liquid crystal permittivity from 2 to 6 at a wavelength of 1.4 mu m. (c) 2007 Optical Society of America.