High-efficiency and tunable circular dichroism in chiral graphene metasurface

2021 ◽  
Author(s):  
Ying Cui ◽  
Xiaosai Wang ◽  
Huan Jiang ◽  
Yongyuan Jiang
Keyword(s):  
Circular Dichroism ◽  
High Efficiency ◽  
Localized Surface Plasmon ◽  
Selective Absorption ◽  
Metal Composite ◽  
Surface Plasmon Resonances ◽  
Localized Surface Plasmon Resonances ◽  
Polarization Control ◽  
Composite Microstructure ◽  
Circular Dichroïsm

Abstract Circular dichroism (CD) response is extremely important for dynamic polarization control, chiral molecular sensing and imaging, etc. Here, we numerically demonstrated high-efficiency and tunable CD using a symmetry broken graphene-dielectric-metal composite microstructure. By introducing slot patterns in graphene ribbons, the metasurface exhibits giant spin-selective absorption for circularly polarized (CP) wave excitations. The maximum CD reaches 0.87 at 2.78 THz, which originates from the localized surface plasmon resonances (LSPRs) in patterned graphene. Besides, the operating frequency and magnitude of CD are dynamically manipulated by gating graphene's Fermi energies. The proposed chiral graphene metasurface with high- efficiency and tunable capability paves a way to the design of active CD metasurfaces.

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

The chiral coating on an achiral nanostructure by the secondary effect in focused ion beam induced deposition

2021 ◽  
Author(s):  
Chen Fang ◽  
Qing Chai ◽  
Ye Chen ◽  
Yan Xing ◽  
Zai-fa Zhou
Keyword(s):  
Circular Dichroism ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Polarized Light ◽  
Localized Surface Plasmon ◽  
Light Illumination ◽  
Secondary Effect ◽  
Circularly Polarized Light ◽  
Optical Metamaterials ◽  
Circular Dichroïsm

Abstract Optical metamaterials are widely used in electromagnetic wave modulation due to their sub-wavelength feature sizes. In this paper, a method to plate an achiral nanopillar array with chiral coating by the secondary effect in focused ion beam induced deposition is proposed. Guided by the pattern defined in a bitmap with variable residence time, the beam scan strategy suppresses the interaction between adjacent nanostructures. A uniform chiral coating is formed on the target nanostructure without affecting the adjacent nanostructure, under carefully selected beam parameters and the rotation angle of the sample stage. Energy Dispersive X-Ray Spectroscopy results show that the chiral film has high purity metal, which enables the generation of localized surface plasmon resonances and causes the circular dichroism under circularly polarized light illumination. Finally, the tailorable circular dichroism spectrum of the coated array is verified by the Finite Difference Time Domain method.

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.

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