Search results for "plasmon"
showing 10 items of 614 documents
Many-body origin of the plasmon resonance in small metal clusters
1994
The origin of the plasmon excitation in small metal clusters is studied within the jellium model through ab initio electronic-structure calculations based on the nuclear shell model. In the limit of infinite size, the plasmon classically represents pure harmonic motion of the center of mass of the valence electrons. It is shown that this limit is already well approximated by clusters of only eight electrons.
Soliplasmon excitations at metal/dielectric/Kerr structures
2009
We present novel optical phenomena based on the existence of a new type of quasi-particle excitation in metal/dielectric/Kerr structures. We discuss the possibility of excitation of surface plasmon polaritons via spatial solitons in these systems.
Plasmon excitations in chemically heterogeneous nanoarrays
2020
| openaire: EC/H2020/838996/EU//RealNanoPlasmon The capability of collective excitations, such as localized surface plasmon resonances, to produce a versatile spectrum of optical phenomena is governed by the interactions within the collective and single-particle responses in the finite system. In many practical instances, plasmonic metallic nanoparticles and arrays are either topologically or chemically heterogeneous, which affects both the constituent transitions and their interactions. Here, the formation of collective excitations in weakly Cu- and Pd-doped Au nanoarrays is described using time-dependent density functional theory. The additional impurity-induced modes in the optical respo…
Quasi-particle and plasmaron properties in the electron gas
1972
The self-energy function of the degenerate electron gas is studied in an approximation which uses the dielectric function proposed by Singwi, Tosi, Land and Sjolander, and neglects the corresponding vertex corrections. Two contributions to the self-energy are distinguished which arise from the plasmon pole and the particle-hole continuum respectively. Comparison of the results is made with the analogous approximation to the self-energy which uses the RPA dielectric function, and with a further, simplified approximation. Subsequently the properties of the usual quasi-particle and of the plasmaron are calculated. Nummerically, the most significant effect found is a 25% reduction of the plasma…
Detection of the optical magnetic field by circular symmetry plasmons
2000
We report on the influence of coating a sharpened optical fiber tip with Au when observing nanofabricated dielectric structures with a Photon Scanning Tunneling Microscope (PSTM) in constant-height mode. For well-defined incident wavelengths and coating thicknesses, we found that such tips detect the distribution of the magnetic field associated with the optical wave in the near-field zone. A simple tip model indicates that this phenomenon is related to the excitation of circular symmetry plasmons in Au coated tips.
A CMOS-compatible Franz-Keldysh effect plasmonic modulator
2014
We present a design of an optimized CMOS-compatible germanium-on-silicon Franz-Keldysh effect plasmonic modulator. Its length is below 30 μm and the modulator operates at −3V. It features a power consumption as low as 20 fJ/bit.
Tunable scattering cancellation of light using anisotropic cylindrical cavities
2016
Engineered core-shell cylinders are good candidates for applications in invisibility and cloaking.In particular, hyperbolic nanotubes demonstrate tunable ultra-low scattering cross section in the visible spectral range. In this work we investigate the limits of validity of the condition for invisibility, which was shown to rely on reaching an epsilon near zero in one of the components of the effective permittivity tensor of the anisotropic metamaterial cavity. For incident light polarized perpendicularly to the scatterer axis, critical deviations are found in low-birefringent arrangements and also with high-index cores. We demonstrate that the ability of anisotropic metallodielectric nanoca…
Robustness of plasmonic angular momentum confinement in cross resonant optical antennas
2015
Using a combination of photoemission electron microscopy and numerical simulations, we investigated the angular moment transfer in strongly enhanced optical near-fields of artificially fabricated optical antennas. The polarization dependence of the optical near-field enhancement has been measured in a maximum symmetric geometry, i.e., excitation by a normal incident planar wave. Finite-difference time-domain simulations for the realistic antenna geometries as determined by high-resolution electron microscopy reveal a very good agreement with experimental data. The agreement confirms that the geometrical asymmetries and inhomogeneities due to the nanoscale fabrication process preserve the ci…
Near-field optical response of a two-dimensional grating of gold nanoparticles
2001
Laboratoire de Physique, Optique Submicronique, Universite´de Bourgogne, Boite Postale 47870, F-21078 Dijon, France~Received 1 August 2000; published 4 April 2001!This article reports on the near-field optical response of a small square grating of gold nanoparticles tailoredby electron-beam lithography. The investigation of the grating is aimed at a deepened understanding ofelectromagnetic interaction among particles due to scattered light fields. Therefore, a photon scanning tunnel-ing microscope is applied to acquire near-field optical images. Two different incident wavelengths are used tocharacterize the intensity and the spatial localization of the electromagnetic near field both in and out…
Unguided plasmon-mode resonance in optically excited thin film: exact modal description of Kretschmann–Raether experiment
2013
With the aim of studying electromagnetic surface wave resonance, we rigorously solve the homogeneous and inhomogeneous problem associated with an optically excited thin metallic film. We then demonstrate unambiguously that the excited eigenmode engendering plasmonic resonance in the so-called Kretschmann–Raether configuration is an unguided mode (i.e., with an anti-evanescent structure). This result, challenging the classical interpretation of the outgoing wave condition applied to surface waves, permits a quantitative interpretation of the attenuated total reflection curves.