We report the focusing of surface plasmon polaritons by circular and elliptical structures milled into optically thick metallic films or plasmonic lenses. Both theoretical and experimental data for the electromagnetic nearfield is presented. The nearfield is mapped experimentally using nearfield scanning optical microscopy and plasmonic lithography. We find that the intensity at the focal point...

Excitation and manipulation of surface plasmons (SPs) are essential in developing cutting-edge plasmonic devices for medical diagnostics, biochemical spectroscopy and communications. The most common approach involves designing an array of periodic slits or grating apertures that enables coupling of the incident light to the SP modes. In recent years, plasmonic resonances, including extraordinar...

Plasmons supported in the massless electron surface states of topological insulators (TIs), known as Dirac plasmons, have great potential next generation optoelectronics. However, their inherent confinement to makes investigation plasmons challenging. Near-field techniques provide ideal platform directly probe due sensitivity evanescent fields at surface. Here, we demonstrate use aperture near-...

Surface plasmons, the quanta of the collective oscillations of free electrons at metal surface, can be easily tuned by changing the surrounding dielectric materials, which is well known for metal nanoparticles and metal surfaces, but less is known for one-dimensional metal nanowires. Here, we find an extremely large tunability of surface plasmons on Ag nanowires with a beat period of the near-f...

This letter presents theory and finite-difference time-domain calculations in excellent agreement with experiments for the transmission of a single subwavelength cylindrical hole in Ag metallic films. The authors discuss the very large enhancement in transmission by single holes in terms of surface plasmons at the interface of the hole. These are similar to the surface plasmons in metallic cyli...

Low-energy electron emission induced by 1–4 keV Ne4þ ion impact on an Al surface was analyzed. Distinct lines observed near 22 eV are attributed to Auger electrons ejected from doubly excited Ne decaying well above the surface. Spectral structures near 11 eV are primarily associated with the decay of bulk plasmons. After instrumental effort of extending the capability of the spectrometer to mea...

At the Center for Fluorescence Spectroscopy, we have taken advantage of the favorable properties of surface plasmon-coupled emission (SPCE) to improve fluorescence-based immunoassays. SPCE occurs when excited fluorophores near conducting metallic structures efficiently couple to surface plasmons. These surface plasmons, appearing as free electron oscillations in the metallic layer, produce elec...

Understanding how surface plasmons can be launched by single subwavelength structures is crucial for the development of surface plasmonbased devices within highly integrated photonic circuits. In this paper, we study the coupling efficiency of light to surface plasmons for single slits milled in a thin metal film by analyzing the far-field optical images recorded in the Fourier plane of a leaka...

Monas Shahzad, Gautam Medhi, Robert E. Peale, Walter R. Buchwald, Justin W. Cleary, Richard Soref, Glenn D. Boreman, and Oliver Edwards Department of Physics, University of Central Florida, Orlando, Florida 32816, USA Solid State Scientific Corporation, 27-2 Wright Road, Hollis, New Hampshire 03049, USA Sensors Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45...

Optical excitation of surface plasmons polaritons (SPPs) on a 'zig-zag diffraction grating' is explored. The fabricated silver grating consists of sub-wavelength grooves 'zig-zagged' along their length, providing a diffractive periodicity to visible radiation. SPPs propagating in the diffraction plane and scattered by an odd number of grating vectors are only excited by TE polarized radiation, ...