scholarly journals Abnormal Fano Profile in Graphene-Wrapped Dielectric Particle Dimer

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 124
Author(s):  
Yang Huang ◽  
Pujuan Ma ◽  
Ya Min Wu
Keyword(s):  
Energy Level ◽  
Theoretical Study ◽  
Dipole Moments ◽  
Near Field ◽  
Field Enhancement ◽  
Plasmon Hybridization ◽  
Far Field ◽  
Wave Polarization ◽  
Fermi Energy Level ◽  
Field Spectrum

We give a theoretical study on the near field enhancement and far field spectrum of an adjacent graphene-wrapped sphere dimer with different radii. The Fano profile is found in the near field enhancement spectrum of such a symmetry-broken dimer system, which is, however, hidden in the far field spectrum. We demonstrate that this kind of Fano profile is rising from the coupling of dimer’s plasmon hybridization modes by analyzing the dipole moments of each sphere. Moreover, different orientation of incident wave polarization will lead to the different plasmon hybridization coupling, thus giving rise to a different Fano profile. By changing the Fermi energy level, we could achieve tunable Fano profile in near field enhancement.

scholarly journals Dye-doped spheres with plasmonic semi-shells: Lasing modes and scattering at realistic gain levels

2013 ◽  
Vol 4 ◽  
pp. 974-987 ◽  
Author(s):  
Nikita Arnold ◽  
Boyang Ding ◽  
Calin Hrelescu ◽  
Thomas A Klar
Keyword(s):  
Cross Section ◽  
Near Field ◽  
Field Enhancement ◽  
Higher Order ◽  
Silver Layer ◽  
Far Field ◽  
Spectral Features ◽  
Polystyrene Spheres ◽  
Higher Order Modes ◽  
Lasing Modes

We numerically simulate the compensation of absorption, the near-field enhancement as well as the differential far-field scattering cross section for dye-doped polystyrene spheres (radius 195 nm), which are half-covered by a silver layer of 10–40 nm thickness. Such silver capped spheres are interesting candidates for nanoplasmonic lasers, so-called spasers. We find that spasing requires gain levels less than 3.7 times higher than those in commercially available dye-doped spheres. However, commercially available concentrations are already apt to achieve negative absorption, and to narrow and enhance scattering by higher order modes. Narrowing of the plasmonic modes by gain also makes visible higher order modes, which are normally obscured by the broad spectral features of the lower order modes. We further show that the angular distribution of the far-field scattering of the spasing modes is by no means dipole-like and is very sensitive to the geometry of the structure.

Active Far-Field Control of the Thermal Near-Field via Plasmon Hybridization

ACS Nano ◽  
2019 ◽  
Vol 13 (8) ◽  
pp. 9655-9663 ◽  
Author(s):  
Ujjal Bhattacharjee ◽  
Claire A. West ◽  
Seyyed Ali Hosseini Jebeli ◽  
Harrison J. Goldwyn ◽  
Xiang-Tian Kong ◽  
...  
Keyword(s):  
Near Field ◽  
Plasmon Hybridization ◽  
Far Field ◽  
Field Control

scholarly journals Effect of Film Thickness on the Far- and Near-Field Optical Response of Nanoparticle-on-Film Systems

2019 ◽  
Author(s):  
Rachel Armstrong ◽  
Willeke van Liempt ◽  
Peter Zijlstra
Keyword(s):  
Film Thickness ◽  
Near Field ◽  
Field Enhancement ◽  
Optical Response ◽  
Resonance Wavelength ◽  
Skin Depth ◽  
Far Field ◽  
Vertical Antenna ◽  
Antenna Mode ◽  
Good Agreement

<p>We study the near-field and far-field optical response of nanoparticle-on-film systems using single-nanoparticle spectroscopy and numerical simulations. We find that the optical spectra contain three dominant modes - a transverse dipole and quadrupole mode, and a dominant vertical antenna mode. We vary the thickness of the metal film from 10 – 45 nm, and find that the vertical antenna mode wavelength is nearly independent of the film thickness. In contrast, we find that the associated near-field enhancement in the gap between the particle and the film strongly depends on the film thickness. This trend is also observed in the far-field where the vertical antenna mode strongly increases in amplitude for increasing film-thicknesses up to the skin depth of gold. These findings are in good agreement with a numerical model and pave the way to study field-mediated processes such as fluorescence, SERS, and localized chemistry at the same resonance wavelength but at varying degrees of field enhancement.</p>

scholarly journals Light-induced symmetry breaking for enhancing second-harmonic generation from an ultrathin plasmonic nanocavity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guang-Can Li ◽  
Dangyuan Lei ◽  
Meng Qiu ◽  
Wei Jin ◽  
Sheng Lan ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Noble Metals ◽  
Second Harmonic ◽  
Near Field ◽  
Field Enhancement ◽  
Plasmonic Nanostructures ◽  
Far Field ◽  
Field Amplification ◽  
Gold Nanosphere

AbstractEfficient frequency up-conversion of coherent light at the nanoscale is highly demanded for a variety of modern photonic applications, but it remains challenging in nanophotonics. Surface second-order nonlinearity of noble metals can be significantly boosted up by plasmon-induced field enhancement, however the related far-field second-harmonic generation (SHG) may also be quenched in highly symmetric plasmonic nanostructures despite huge near-field amplification. Here, we demonstrate that the SHG from a single gold nanosphere is significantly enhanced when tightly coupled to a metal film, even in the absence of a plasmon resonance at the SH frequency. The light-induced electromagnetic asymmetry in the nanogap junction efficiently suppresses the cancelling of locally generated SHG fields and the SH emission is further amplified through preferential coupling to the bright, bonding dipolar resonance mode of the nanocavity. The far-field SHG conversion efficiency of up to $$3.56\times 10^{-7}$$ 3.56 × 1 0 − 7 W−1 is demonstrated from a single gold nanosphere of 100 nm diameter, two orders of magnitude higher than for complex double-resonant plasmonic nanostructures. Such highly efficient SHG from a metal nanocavity also constitutes an ultrasensitive nonlinear nanoprobe to map the distribution of longitudinal vectorial light fields in nanophotonic systems.

Sign in / Sign up

Export Citation Format

Share Document