We present a straightforward method to double the refractive index sensitivity of surface-supported nanoplasmonic optical sensors by lifting the metal nanoparticles above the substrate by a dielectric nanopillar. The role of the pillar is to substantially decrease the spatial overlap between the substrate and the enhanced fields generated at plasmon resonance. Data presented for nanodisks and nanoellipsoids supported by pillars of varying heights are found to be in excellent agreement with electrodynamics simulations. The described concepts apply to multitude of plasmonic nanostructures, fabricated by top-down or bottom-up techniques, and are likely to further facilitate the development of novel nanooptical sensors for biomedicine and diagnostics.

We introduce a new perspective on magnetoplasmonics in nickel nanoferromagnets by exploiting the phase tunability of the optical polarizability due to localized surface plasmons and simultaneous magneto-optical activity. We demonstrate how the concerted action of nanoplasmonics and magnetization can manipulate the sign of rotation of the reflected light’s polarization (i.e., to produce Kerr rotation reversal) in ferromagnetic nanomaterials and, further, how this effect can be dynamically controlled and employed to devise conceptually new schemes for biochemosensing.

We report on a dramatic directionality effect in a simple and ultracompact optical nanoantenna consisting of a pair of interacting plasmonic nanoparticles. We found that the emission from a dipole source positioned close to one of the particles in the pair exhibits an essentially unidirectional radiation pattern for emission wavelengths close to the antiphase hybridized plasmon. We analyze this unique effect in terms of radiation, reception, and reciprocity concepts using electrodynamics simulations and dipole analysis. A forward-backward directionality of approximately 18 dB at 665 nm is obtained for a nanoantenna that consists of two 90 nm wide and 20 nm thick gold nanodisks separated by a 10 nm gap.

The optical properties of single nanoholes in optically thin (t=20 nm) gold films on glass have been studied experimentally and theoretically. The measured elastic scattering spectra from the nanoholes exhibit a broad resonance in the red part of the visible spectrum, which is qualitatively similar to localized surface

A metal–dielectric sandwich nanostructure, fabricated by a self‐assembly technique, has a bimodal resonant response at optical frequencies due to dipolar plasmon hybridization (see picture). The degree of electromagnetic coupling in the system can be controlled by either varying the aspect ratio of one of the disks in the layered structure, or by altering the thickness of the dielectric spacer between the plasmonic components.