Mode structure of planar optical antennas on dielectric substrates.

TL;DR: The spectral responses of the two hybridized modes on the dolmen structures as the pitch size changed evolved in a manner similar to that of the bright dipole mode on the nanoblocks, whereas the dark mode onThe heptamer structures is less sensitive to the pitchsize.

TL;DR: This paper presents three cases of surface near-fields imaged in PEEM: an indium tin oxide photonic waveguide, a large gold plasmonic patch antenna, and a small gold plAsmonic slot antenna and compares and contrast the use of normal and oblique incidence for each case.

Abstract: The plasmonics dark mode of metal nanorings has potential in the field of e.g. sensing and surface-enhanced Raman spectroscopy (SERS). Most of the investigations on the plasmonics dark mode in a nanoring have been on far-field spectroscopy or near field simulations so far. In this paper, the near-field distribution of the femtosecond dark mode plasmon on an individual gold nanoring is mapped non-invasively using photoemission electron microscopy (PEEM). The experimental results show that strong electron emission distributions in the PEEM images under different polarization directions and wavelengths of femtosecond light are in qualitative agreement with the pattern of quadruple plasmon mode calculated using finite-difference time-domain simulation. In the meantime, it is found that there is a discrepancy in hot spot distribution between the observed PEEM image and the simulated photoelectron emission pattern, which is attributed to some possible factors, such as band structure near the Fermi level of the nanoring material and the temporal profile of femtosecond laser pulse. Real-space near-field imaging of the plasmonics dark mode provides a fundamental understanding of the near field and paves the way for further advancing the applications of dark mode in the field of e.g. sensing and SERS.

TL;DR: An operation mode in which the spatiotemporal dynamics following a highly local excitation of the sample is globally probed with a laser pulse illuminating the sample from the front side is demonstrated.

TL;DR: Optical antennas are devices that convert freely propagating optical radiation into localized energy, and vice versa as mentioned in this paper, and hold promise for enhancing the performance and efficiency of photodetection, light emission and sensing.

TL;DR: The role of plasmonic resonances on the performance of nanoantennas and the influence of geometrical parameters imposed by nanofabrication are discussed.

TL;DR: Long-range surface plasmon polaritons (LRSPPs) are optical surface waves that propagate along a thin symmetric metal slab or stripe over an appreciable length as discussed by the authors.

TL;DR: In this paper, the authors provide details of fabrication and characterization of these new materials and discuss their suitability for a number of metamaterial and plasmonic applications, as well as their properties.