scholarly journals Broadband absorption using all-graphene grating-coupled nanoparticles on a reflector

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shiva Hayati Raad ◽  
Zahra Atlasbaf ◽  
Carlos J. Zapata-Rodríguez
Keyword(s):  
Surface Plasmons ◽  
Transverse Magnetic ◽  
Spherical Particles ◽  
Localized Surface Plasmon ◽  
Surface Plasmon Resonances ◽  
Bandwidth Enhancement ◽  
Broadband Absorption ◽  
Localized Surface Plasmon Resonances ◽  
Hyperbolic Dispersion ◽  
Dynamic Bandwidth

Abstract In this paper, the hybridized localized surface plasmon resonances (LSPRs) of a periodic assembly of graphene-wrapped nanoparticles are used to design a nanoparticle assisted optical absorber. Bandwidth enhancement of this structure via providing multiple types of plasmonic resonances in the associated unit cell using two densely packed crossly stacked graphene strips is proposed. The designed graphene strips support fundamental propagating surface plasmons on the ribbons, and gap plasmons in the cavity constructed by the adjacent sections. Graphene strips exhibit a hyperbolic dispersion region in the operating spectrum and assist in the bandwidth enhancement. Moreover, since the nanoparticles are deposited on the top strips, real-time biasing of them can be easily conducted by exciting the surface plasmons of the strip without the necessity to electrically connect the adjacent nanoparticles. The overall dynamic bandwidth of the structure, using a two-state biasing scheme, covers the frequencies of 18.16–40.47 THz with 90% efficiency. Due to the symmetry of the structure, the device performs similarly for both transverse electric (TE) and transverse magnetic (TM) waves and it has a high broadband absorption rate regarding different incident angles up to 40°. Due to the presence of 2D graphene material and also using hollow spherical particles, our proposed absorber is also lightweight and it is suitable for novel compact optoelectronic devices due to its sub-wavelength dimensions.

scholarly journals Probing the symmetry of the potential of localized surface plasmon resonances with phase-shaped electron beams

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Giulio Guzzinati ◽  
Armand Béché ◽  
Hugo Lourenço-Martins ◽  
Jérôme Martin ◽  
Mathieu Kociak ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Electron Beams ◽  
Localized Surface Plasmon ◽  
Surface Plasmon Resonances ◽  
Localized Surface Plasmon Resonances ◽  
Plasmon Resonances

Tunable localized surface plasmon resonances of asymmetric Au/SiO2/Au cross-shape nanobars

2014 ◽  
Vol 28 (17) ◽  
pp. 1450143 ◽  
Author(s):  
M. L. Wan ◽  
H. J. Du ◽  
Y. L. Song ◽  
F. Q. Zhou ◽  
K. J. Dai
Keyword(s):  
Electric Fields ◽  
Surface Plasmon ◽  
Near Infrared ◽  
Dipole Approximation ◽  
Localized Surface Plasmon ◽  
Surface Plasmon Resonances ◽  
Localized Surface Plasmon Resonances ◽  
Plasmon Resonances ◽  
Surface Enhanced Raman ◽  
Infrared Spectral

The plasmonic properties of asymmetric Au / SiO 2/ Au sandwiched cross-shape nanobars are investigated theoretically using the discrete dipole approximation (DDA) method. Two localized surface plasmon resonances are observed in the extinction spectra, which perform extreme sensitivity to the length and width of the nanobar and can be tuned easily throughout visible and into near-infrared spectral regions. The local electric fields around the nanobar are calculated and a pure electromagnetic Raman enhancement factor of about 106 can be achieved. In addition, compared to a monolayer gold nanobar, it exhibits more "hot spots" and stronger localized electric field enhancements. This plasmonic substrate provides potential applications in surface enhanced Raman scattering (SERS) and nonlinear optical devices.

scholarly journals Unconventional Optical Response in Engineered Au-Ag Nanostructures

2019 ◽  
Author(s):  
Dev Kumar Thapa ◽  
Subham Kumar Saha ◽  
Guru Pratheep Rajasekar ◽  
Biswajit Bhattacharyya ◽  
Rekha Mahadevu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Surface Plasmon ◽  
Mie Theory ◽  
Localized Surface Plasmon ◽  
Silver Particles ◽  
Temperature Dependent ◽  
Surface Plasmon Resonances ◽  
Localized Surface Plasmon Resonances ◽  
Plasmon Resonances ◽  
Diamagnetic State

This article describes the optical properties of nanostructures composed of silver particles embedded into a gold matrix. In previous studies these materials were shown to exhibit temperature dependent transitions to a highly conductive and strongly diamagnetic state. Here we describe the anomalous optical properties of these nanostructures. Most notably, these materials fail to obey Mie theory and exhibit an unconventional resonance with a maximum at about 4 eV, while the usual gold and silver localized surface plasmon resonances are suppressed. This effect implies a significant deviation from the bulk dielectric functions of gold and silver. We further resolved this resonance into its absorbance and scattering sub-parts. It is observed that the resonance is largely comprised of scattering, with negligible losses even at ultraviolet frequencies.

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