11 research outputs found
Measuring the mode volume of plasmonic nanocavities using coupled optical emitters
Metallic optical systems can confine light to deep sub-wavelength dimensions,
but verifying the level of confinement at these length scales typically
requires specialized techniques and equipment for probing the near-field of the
structure. We experimentally measured the confinement of a metal-based optical
cavity by using the cavity modes themselves as a sensitive probe of the cavity
characteristics. By perturbing the cavity modes with conformal dielectric
layers of sub-nm thickness using atomic layer deposition, we find the
exponential decay length of the modes to be less than 5% of the free-space
wavelength (\lambda) and the mode volume to be of order \lambda^3/1000. These
results provide experimental confirmation of the deep sub-wavelength
confinement capabilities of metal-based optical cavities.Comment: 11 pages, 4 figure
Far-Infrared Graphene Plasmonic Crystals for Plasmonic Band Engineering
We introduce far-infrared graphene plasmonic crystals. Periodic structural perturbation—in a proof-of-concept form of hexagonal lattice of apertures—of a continuous graphene medium alters delocalized plasmonic dynamics, creating plasmonic bands in a manner akin to photonic crystals. Fourier transform infrared spectroscopy demonstrates band formation, where far-infrared irradiation excites a unique set of plasmonic bands selected by phase matching and symmetry-based selection rules. This band engineering may lead to a new class of graphene plasmonic devices
Plasmonics with two-dimensional conductors
A wealth of effort in photonics has been dedicated to the study and engineering of surface plasmonic waves in the skin of three-dimensional bulk metals, owing largely to their trait of subwavelength confinement. Plasmonic waves in two-dimensional conductors, such as semiconductor heterojunction and graphene, contrast the surface plasmonic waves on bulk metals, as the former emerge at gigahertz to terahertz and infrared frequencies well below the photonics regime and can exhibit far stronger subwavelength confinement. This review elucidates the machinery behind the unique behaviours of the two-dimensional plasmonic waves and discusses how they can be engineered to create ultra-subwavelength plasmonic circuits and metamaterials for infrared and gigahertz to terahertz integrated electronics
Symmetry Engineering of Graphene Plasmonic Crystals
The
dispersion relation of plasmons in graphene with a periodic lattice
of apertures takes a band structure. Light incident on this plasmonic
crystal excites only particular plasmonic modes in select bands. The
selection rule is not only frequency/wavevector matching but also
symmetry matching, where the symmetry of plasmonic modes originates
from the point group symmetry of the lattice. We demonstrate versatile
manipulation of light-plasmon coupling behaviors by engineering the
symmetry of the graphene plasmonic crystal
Ultra-Subwavelength Two-Dimensional Plasmonic Circuits
We report electronics regime (GHz) two-dimensional (2D)
plasmonic
circuits, which locally and nonresonantly interface with electronics,
and thus offer to electronics the benefits of their ultrasubwavelength
confinement, with up to 440,000-fold mode-area reduction. By shaping
the geometry of 2D plasmonic media 80 nm beneath an unpatterned metallic
gate, plasmons are routed freely into various types of reflections
and interferences, leading to a range of plasmonic circuits, e.g.,
plasmonic crystals and plasmonic-electromagnetic interferometers,
offering new avenues for electronics