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

Pearls of experience for safe and efficient hospital practices in otorhinolaryngology—head and neck surgery in Hong Kong during the 2019 novel coronavirus disease (COVID-19) pandemic

<jats:title>Abstract</jats:title><jats:p>The 2019 novel coronavirus disease (COVID-19) epidemic originated in Wuhan, China and spread rapidly worldwide, leading the World Health Organization to declare an official global COVID-19 pandemic in March 2020. In Hong Kong, clinicians and other healthcare personnel collaborated closely to combat the outbreak of COVID-19 and minimize the cross-transmission of disease among hospital staff members. In the field of otorhinolaryngology—head and neck surgery (OHNS) and its various subspecialties, contingency plans were required for patient bookings in outpatient clinics, surgeries in operating rooms, protocols in wards and other services. Infected patients may shed severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) particles into their environments via body secretions. Therefore, otolaryngologists and other healthcare personnel in this specialty face a high risk of contracting COVID-19 and must remain vigilant when performing examinations and procedures involving the nose and throat. In this article, we share our experiences of the planning and logistics undertaken to provide safe and efficient OHNS practices over the last 2 months, during the COVID-19 pandemic. We hope that our experiences will serve as pearls for otolaryngologists and other healthcare personnel working in institutes that serve large numbers of patients every day, particularly with regard to the sharing of clinical and administrative tasks during the COVID-19 pandemic.</jats:p&gt