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We demonstrate a parabolic reflector nanoantenna as a structure for directivity-enhanced Raman scattering (DERS). This antenna consists of a nanoscale paraboloid shaped Au reflector and an Ag nanoprism feed element. We experimentally test this nanoantenna and obtain a 22× enhancement to the Raman signal from nanoantenna structures with planar reflectors, and estimate a 1100× enhancement to the surface-enhanced Raman scattering (SERS) from the Ag nanoprism alone. A comprehensive finite-difference time-domain simulation is used to model the field intensity in the parabolic reflector nanoantenna, confirming its better coupling between the near- and the far-field. Moreover, we describe a possible method to obtain an even higher SERS gain from our structure. [ABSTRACT FROM PUBLISHER]

Near-field scanning optical microscopes (NSOMs) enable one to perform subwavelength optical imaging by scanning a nanosized probe in the near field at the surface of a specimen. NSOMs generally use a subwavelength aperture, a scattering tip, or a fluorescent nanoobject as local probes of the near-field. We review the basic principles of the different types of NSOMs. Illustrative examples are given to show how these probes can be used to perform optical mapping and characterization of materials with nanoscopic resolution. [ABSTRACT FROM AUTHOR]

A nanodiamond (ND) hosting nitrogen-vacancy (NV) color centers is attached on the apex of an optical tip for near-field microscopy. Its fluorescence is used to launch surface plasmon-polaritons (SPPs) in a thin polycrystalline gold film. It is shown that the quantum nature of the initial source of light is preserved after conversion to SPPs. This opens the way to a deterministic quantum plasmonics, where single SPPs can be injected at well-defined positions in a plasmonic device produced by top-down approaches. [ABSTRACT FROM AUTHOR]