Metallic metamaterials and plasmonics.

Our ability to control and harness light is undergoing a revolution, one that exploits the special properties of metals and our ability to structure them on a subwavelength scale. The materials that enable such control involve plasmonic and metallic metamaterials, materials that provide challenges for physicists and engineers that demand a multi-disciplinary approach. In June 2010, Alastair Hibbins, Roy Sambles and I brought together scientists from different subdisciplines to exchange knowledge and forge new ideas at the first Theo Murphy Royal Society Discussion Meeting held at the Royal Society’s new meeting venue, the Kavli Centre at Chicheley Hall. The papers in this issue are drawn from that meeting and provide a fascinating cross section in the development of this new interdisciplinary area. The same conduction electrons in metals that are responsible for their highly reflective character are being exploited to yield many new and fascinating possibilities ranging from invisibility cloaks to perfect lensing. These new possibilities rely on our ability to structure metals at the subwavelength scale, thereby creating novel materials with properties that allow one to transcend the boundaries of traditional optics. The two realms of metamaterials and plasmonics both depend critically on sub-wavelength structure, in plasmonics it is primarily single or a small number of structures that are of interest, while in metamaterials it is usually arrays of structures that are important. There is an increasing overlap between these two fields, one we sought to pursue in this Discussion Meeting. Metamaterials have attracted great interest beyond just the research community, primarily because of a plethora of recent theoretical and experimental results that have sparked the public’s imagination. For example, suitably structured metallic metamaterials have been found to give negative refractive index, sub-wavelength confinement and control of light and to provide very strong optical field enhancements. However, it is perhaps the demonstration of electromagnetic cloaking, rendering objects invisible, which has generated the most excitement. In plasmonics also new developments continue, which include exciton–plasmon coupling, coherent control of sub-wavelength optical manipulation and plasmon-assisted high harmonic generation. Taken together, these and other developments have led to an explosion of interest worldwide in metallic metamaterials. These new materials pose fascinating challenges for experimentalists and theorists, challenges that are driving forward new techniques and new conceptual approaches. Experimentalists are developing procedures to fabricate and characterize new metallic structures, while theorists are grappling with the