Coupling Effects in Optical Metamaterials

• Published in: Angewandte Chemie International Edition 2010-12, Vol.49 (51), p.9838-9852
• Main Authors: Liu, Na, Giessen, Harald
• Format: Article
• Language: English
• Subjects: interactions; metamaterials; nanostructures; photonics
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.200906211

Metamaterials have become one of the hottest fields of photonics since the pioneering work of John Pendry on negative refractive index, invisibility cloaking, and perfect lensing. Three‐dimensional metamaterials are required for practical applications. In these materials, coupling effects between individual constituents play a dominant role for the optical and electronic properties. Metamaterials can show both electric and magnetic responses at optical frequencies. Thus, electric as well as magnetic dipolar and higher‐order multipolar coupling is the essential mechanism. Depending on the structural composition, both longitudinal and transverse coupling occur. The intricate interplay between different coupling effects in a plasmon hybridization picture provides a useful tool to intuitively understand the evolution from molecule‐like states to solid‐state‐like bands. A negative refractive index is an example of the fascinating properties that are unattainable in naturally occurring materials but can be engineered into artificially structured metamaterials. This Review gives an overview of the coupling principles and highlights the coupling effects in simple to complex optical metamaterials. The picture shows a four‐layer stacked split‐ring resonator metamaterial prepared by a layer‐by‐layer nanotechnique.