Photonic Approach to Making a Left-Handed Material

A new approach to producing a composite material with negative refraction index is demonstrated. It is shown that a photonic structure which consists of two dielectric materials, with positive and negative dielectric permittivities, can support electromagnetic waves which exhibit the unusual electromagnetic property of left-handedness (or negative refraction index). These electromagnetic waves are the surface waves localized at the dielectric interfaces. Depending on the geometry of the photonic structure, the composite left-handed material can be either isotropic, or anisotropic. Left-handed materials (LHMs) [1] with negative magnetic permeability μ and dielectric permittivity ǫ have recently attracted a great deal of attention because of their promise for developing novel lenses and low reflectance surfaces [2,3]. LHMs have a negative refractive index, which implies that the phase and group velocities of the propagating electromagnetic wave oppose each other. This property of LHMs is responsible for their anomalous physical behavior: reversed sign of the Doppler effect and counter-intuitive refraction at the interface with the ”normal” (right-handed) media [1]. Since materials with μ < 0 do not naturally occur, LHM has to be artificially constructed. An LHM in the microwave frequency band was recently constructed as an array consisting of metal rods (which provided ǫ < 0 [4]) and split-ring resonators (which provided μ < 0 [5]). Photonic structures have also been known to exhibit negative group velocity due to the band folding effect [6]. In this Letter I introduce a new concept of making an LHM by creating