Recent Advances in Graphene Based Plasmonics

Plasmonics is an emerging and fast-growing branch of science and technology that focuses on the coupling of light to the free electron density in metals, resulting in strong electromagnetic field enhancement due to confinement of light into sub-wavelength dimensions beyond the diffraction limit. The development of novel photonic and optoelectronic devices based on metal-based plasmonics is however plagued by the high loss at optical frequencies, originating partly from inter-band electronic transitions and lack of electrical tunability, practically limiting their potential applications in the terahertz (THz) and mid-IR spectrum range. The recent successful exfoliation of graphene from graphite has rendered a breakthrough in the realm of plasmonics due to its phenomenal properties such as exceptionally tight light confinement, extremely long plasmon lifetime, high carrier mobility leading to a relatively low level of losses, strong optical nonlinearity and electrostatically as well as chemically tunable response. These versatile features of graphene can effectively address the challenges faced by metals, and hence the physics and potential applications of graphene-based plasmonics have triggered increasing attention of industry, academic and research fraternity in recent years. This chapter provides a comprehensive description of the theoretical approaches adopted to investigate the dispersion relation of graphene surface plasmons, types of graphene surface plasmons and their interactions with photons, phonons and electrons, experimental techniques to detect surface plasmons, the behaviour of surface plasmons in graphene nanostructures and the recent applications of graphene-based plasmonics.

Keywords: Graphene, Graphene Nanostructures, Mid-infrared Photonics, Plasmonics, Quasi-Particles, Tunability, Terahertz Photonics.