A Study on the Coupling Effects between Constituent Elements of Metamaterials

Abstract

The emerging field of artificially engineered materials, the so-called metamaterials (MMs), has opened a new gateway to unprecedented electromagnetic properties and functionalities, which are unattainable in naturally occurring materials. Recently, a new and promising direction has been revealed in the MM research - the study on MMs using the coupling effects. This advancement has greatly expanded the playground of MMs because of many unique properties, which do not appear in the conventional MMs, are achieved in the coupled ones. This thesis is, therefore, devoted to study the physics of electromagnetic couplings between constituents in MMs, and consider how these effects can be utilized in tailoring the properties of MMs in specific cases. By considering the basic propagation properties of light in the effective medium of MM and its interactions with the MM building blocks, the electromagnetic coupling between resonant elements are generally considered in terms of the Lagrangian formalism.

Next, I go into detail to investigate the in-plane coupling between neighboring cut-wire pairs (CWPs) in planar structures. Interestingly, this interaction can provide an additional degree of freedom to the resonance engineering of the CWP-based MMs. Furthermore, by considering in detail the coupling between two electric elements of very different resonant quality factors, I was successful to elucidate the underlying basic physics of a very fascinating phenomena - the so-called electromagnetically-induced transparency (EIT)-like effect. The potential applications employing those MMs, such as multiple resonance engineering and slow-light effects, are also discussed.