Detuning Conditions for Negative Dielectric in Optical Metamaterials

摘要

The study of theoretical optical metamaterials provides no detail insight of the atomic and molecular level of bulk matter with respect to negative n. Instead, most theoretical research starts from a different point of departure; an elemental metallic artificial structure that exhibits R, L and C and thus resonance. Manipulating the size and the periodicity of such elements in a larger structure, the phase relationship of a propagating electromagnetic wave through it and for a specific range of frequencies causes the phase to move in opposite direction of the Pointing vector. This phenomenon, demonstrated for microwave but not for optical frequencies yet, has certain interesting properties among them negative permeability and negative dielectric constant. In this paper, in contrast to this approach, our point of departure is on the atomic level of matter based on which we express the negative dielectric constant ε(ω) in terms of frequency detuning and also in terms of atomic density and we derive the detuning conditions for ε(ω) ＜ 0. We believe that these conditions provide a useful guide towards the design of optical metamaterials.