Abstract
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.