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Electromagnetic toroidal excitations in matter and free space
N Papasimakis1, V A Fedotov1, V Savinov1
1Optoelectronics Research Centre &Centre for Photonic Metamaterials, University of Southampton, Highfield SO17 1BJ, UK.
Nature Materials
|February 25, 2016
Summary
Toroidal dipoles, a unique electromagnetic excitation, significantly impact material properties and can form non-radiating anapoles. Their study in metamaterials opens new avenues in photonics and sensing.
Area of Science:
- Electromagnetism and Optics
- Metamaterials Science
Background:
- The toroidal dipole is a distinct electromagnetic excitation characterized by currents on a torus surface.
- Unlike electric and magnetic dipoles, toroidal dipoles offer unique contributions to material properties like absorption and optical activity.
- Toroidal excitations can manifest as localized electromagnetic pulses in free space.
Purpose of the Study:
- To review recent experimental observations of resonant toroidal dipole excitations in metamaterials.
- To highlight the discovery and significance of anapoles, which involve toroidal dipoles.
- To explore the potential implications of toroidal electrodynamics in various scientific fields.
Main Methods:
- Review of experimental observations in metamaterials.
- Analysis of anapole configurations involving toroidal dipoles.
- Theoretical considerations of toroidal electrodynamics.
Main Results:
- Experimental evidence of resonant toroidal dipole excitations in metamaterials has been observed.
- Anapoles, non-radiating configurations utilizing toroidal dipoles, have been discovered.
- Toroidal dipoles demonstrably influence fundamental material characteristics.
Conclusions:
- Toroidal excitations, particularly in metamaterials, show promise for advanced applications.
- The study of anapoles and toroidal dipoles is crucial for future developments in photonics, sensing, energy, and information.
- Further research into toroidal electrodynamics is expected to yield significant fundamental and practical advancements.
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