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Updated: Dec 12, 2025
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Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures
Published on: November 21, 2019
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Active Plasmonics and Active Chiral Plasmonics through Orientation-Dependent Multipolar Interactions
Peter R Stevenson1, Matthew Du2, Charles Cherqui3
1Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States.
ACS Nano
|August 14, 2020
Summary
Orientation control of passive plasmonic materials offers a simple method to achieve active plasmonic and chiral plasmonic responses. This technique tunes optical extinction and switches chiroptical handedness by manipulating substrate orientation relative to incident light.
Area of Science:
- Plasmonics
- Nanophotonics
- Materials Science
Background:
- Active plasmonic metamaterials typically rely on complex responsive designs.
- Passive plasmonic materials, while simpler to fabricate, lack post-fabrication tunability.
- Controlling light-matter interactions is key to advanced optical functionalities.
Purpose of the Study:
- To demonstrate a simple method for achieving active plasmonic and chiral plasmonic responses from passive plasmonic materials.
- To explore the use of substrate orientation control for tuning optical properties.
- To investigate the role of multipolar effects in orientation-dependent plasmonic behavior.
Main Methods:
- Utilizing gold nanocrescents as a model system for passive plasmonic structures.
- Implementing substrate orientation control relative to incident light polarization and angle.
- Characterizing optical extinction and chiroptical responses (Δg) as a function of orientation.
- Correlating observed responses with multipolar polarizabilities (magnetoelectric, dipole-quadrupole).
Main Results:
- Achieved tunable optical extinction ranging from -21% to +36% by varying substrate orientation.
- Demonstrated controllable switching of chiroptical handedness (Δg = ± 0.55).
- Linked active plasmonic and chiral responses to the multipolar character of resonant modes.
- Observed sensitivity of optical characterization to subtle structural variations (tip asymmetry).
Conclusions:
- Substrate orientation control provides a facile route to active plasmonics and chiral plasmonics using passive materials.
- Multipolar effects, including magnetoelectric and dipole-quadrupole polarizabilities, govern orientation-dependent light-matter interactions.
- Orientation-dependent optical characterization is highly sensitive to electromagnetic field gradients and nanoscale structural details.
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