The effect of nanoscale surface roughness on the gap plasmon resonance of gold nanoparticles on thermally evaporated gold films is investigated experimentally and numerically. Single-particle scattering spectra obtained from 80 nm diameter gold particles on a gold film show significant particle-to-particle variation of the peak scattering wavelength of ±28 nm. The experimental results are compa...

We present a numerical study of the tunability properties of a plasmonic subwavelength particle deposited on a metallic slab. The particle is composed of a metallic part, supporting a localized plasmon mode, separated from the slab by a dielectric spacer. It is shown that the position of the resonance wavelength can be modified over a large spectral range by changing either the spacer thickness...

Hyperbolic metamaterials (HMM) are of great interest due to their ability to break the diffraction limit for imaging and enhance near-field radiative heat transfer. Here we demonstrate that an annular, transparent HMM enables selective heating of a sub-wavelength plasmonic nanowire by controlling the angular mode number of a plasmonic resonance. A nanowire emitter, surrounded by an HMM, appears...

We report the label-free, real-time optical detection of Influenza A virus particles. Binding of single virions is observed from discrete changes in the resonance frequency/wavelength of a whispering-gallery mode excited in a microspherical cavity. We find that the magnitude of the discrete wavelength-shift signal can be sufficiently enhanced by reducing the microsphere size. A reactive sensing...

We report the demonstration of electro-optical tunable time delay and advance using a silicon feedback-microring resonator integrated with p-i-n diodes. By controlling the feedback and round-trip phase shifts through the carrier-injection-based free-carrier dispersion effect, we obtain a large dynamic time tuning range (-88 ps to 110 ps) upon dc bias voltage change in the range of few tens of m...

We propose a biosensor by exploiting localized plasmons in graphene and biomolecule adsorption on it. Numerical simulations demonstrate that the sensitivity of such a device can achieve a high value of up to 1697 nm/RIU (refractive index unit) when the wavelength shift at the plasmon resonance is detected. The transparent substrate supporting graphene can be chosen potentially from a wide range...

A defect grating in a silicon on insulator waveguide is simulated. We consider spectral changes in the optical transmission when a thin silicon nitride or silicon tip is scanned across the defect. The tip perturbs the resonance field, moving its peak wavelength and possibly changing its shape and quality factor. For the nitride tip, the influence is mostly a spectral shift; for silicon, the cha...

We design a photonic sphere-array nanoantenna (NA) exhibiting both strong directionality and wavelength selectivity. Although the geometric configuration of the photonic NA resembles a plasmonic Yagi-Uda NA, it has different working principles and, most importantly, reduces the inherent metallic loss from plasmonic elements. For any selected optical wavelength, a sharp Fano resonance by the ref...

Our experiment shows that the thermal emission of phonon can be controlled by magnetic resonance (MR) mode in a metasurface (MTS). Through changing the structural parameter of metasurface, the MR wavelength can be tuned to the phonon resonance wavelength. This introduces a strong coupling between phonon and MR, which results in an anticrossing phonon-plasmons mode. In the process, we can manipu...

Specular resonance by periodic bilayer cylinders is electromagnetically analyzed for the first time to our knowledge. The phenomenon occurs when the radius is roughly 0.8 times the wavelength. It is also discovered that the structure behaves as a good guided-mode resonant grating filter when the radius is around 0.4 times the wavelength.