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Updated: Jun 4, 2025
08:54
Performing Spectroscopy on Plasmonic Nanoparticles with Transmission-Based Nomarski-Type Differential Interference Contrast Microscopy
Published on: June 5, 2019
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Fano Resonance-Associated Plasmonic Circular Dichroism in a Multiple-Dipole Interaction Born-Kuhn Model
Wanlu Bian1,2, Guodong Zhu1, Fengcai Ma3
1School of Physics, Dalian University of Technology, Dalian 116024, China.
Sensors (Basel, Switzerland)
|December 17, 2024
Summary
Chiral plasmonic nanodisk dimers exhibit strong circular dichroism (CD) through coupled dipole and hexapole modes. This phenomenon shows promise for highly sensitive refractive index sensing applications.
Area of Science:
- Plasmonics
- Nanophotonics
- Chiral Optics
Background:
- Plasmon chirality is crucial for sensing due to localized fields and tunable optical properties.
- Understanding mode coupling in chiral structures is key to enhancing chiral optical activity.
Purpose of the Study:
- To numerically investigate circular dichroism (CD) in elliptical nanodisk dimers.
- To explore the impact of dipole and electric hexapole mode coupling on CD.
- To assess the potential for refractive index sensing.
Main Methods:
- Numerical simulation of elliptical nanodisk dimers in an up-and-down configuration.
- Adjustment of inter-particle distance and geometric parameters.
- Analysis of circular dichroism (CD) and Fano resonance.
Main Results:
- Coupling between dipole and electric hexapole modes creates an extended Born-Kuhn model, yielding strong CD.
- Observed obvious Fano resonance and strong CD effects due to mode coupling.
- The highest CD correlated with the largest Fano asymmetry factor.
Conclusions:
- Elliptical nanodisk dimers effectively generate strong circular dichroism via mode coupling.
- The observed Fano resonance and CD are sensitive to refractive index changes.
- This plasmonic system demonstrates potential for high-sensitivity refractive index sensing.
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