Meta-atoms Emulating Quantum Systems

Abstract

Electromagnetic property of a medium can be derived from electric and/or magnetic response of constituent atoms or molecules. If an artificial structure called meta-atom is designed to show the same response for the incidence of electromagnetic waves, the assembly of the meta-atoms, or metamaterial, is expected to exhibit the same functionality as that of the atomic medium. In this chapter, we focus on metamaterials mimicking electromagnetically induced transparency (EIT) effect, which has been extensively investigated in atomic systems composed of three-level atoms. We start with an analogy between a two-level atom and a meta-atom with a single resonant mode as a simplest example. Next, we provide rigorous analogy between an atomic medium with three-level atoms showing EIT effects and the metamaterial composed of coupled resonator-based meta-atoms, comparing the atomic response derived from Schrodinger equations of the quantum system and the response of the meta-atom derived from the circuit equations of its circuit model. Based on the coupled resonator model, several examples of metamaterials showing EIT-related effects such as sharp transparency and slow propagation are introduced. We also introduce a tunable metamaterial, which realizes storage of electromagnetic waves in the same way as the atomic EIT system.