From Scattering Parameters to Snell's Law: A Subwavelength Near-Infrared Negative-Index Metamaterial

A general relation is derived between the band structure of an arbitrary low-loss unit cell and its effective index of refraction. In addition, we determine the maximum unit cell size that defines the metamaterial regime [D. R. Smith , Phys. Rev. E 71, 036617 (2005)]. Furthermore, these general rules allow for the design of a subwavelength near-infrared negative-index material, where the negative refractive index is verified by band calculations to be a bulk property. Full-wavelength simulations of prisms consisting of these unit cells suggest behavior consistent with Snell's law in the negative-index regime.