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Radiative Toroidal Dipole and Anapole Excitations in Collectively Responding Arrays of Atoms
K E Ballantine1, J Ruostekoski1
1Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom.
Physical Review Letters
|August 27, 2020
Summary
Researchers demonstrate synthesizing toroidal dipoles using coupled atoms, creating novel electromagnetic excitations. This work also explores dynamic anapoles, which cancel toroidal dipole radiation for advanced applications.
Area of Science:
- Electromagnetism and Atomic Physics
- Quantum Optics and Photonics
Background:
- Toroidal dipoles are distinct electromagnetic excitations, often overlooked in multipole expansions.
- Understanding toroidal dipoles is crucial for developing novel optical and electromagnetic phenomena.
Purpose of the Study:
- To demonstrate a method for synthesizing toroidal dipoles using radiatively coupled atoms.
- To explore the creation of collective excitation modes and dynamic anapoles.
Main Methods:
- Utilizing strongly radiatively coupled atoms to form an effective poloidal electric current.
- Developing protocols for preparing delocalized collective excitation modes.
- Investigating the cancellation of toroidal dipole radiation by electric dipoles.
Main Results:
- Successfully synthesized toroidal dipoles through radiative transitions in coupled atoms.
- Developed methods for creating synthetic lattices of toroidal dipoles.
- Identified dynamic anapole configurations where toroidal dipole radiation is canceled by electric dipoles.
Conclusions:
- Coupled atoms provide a viable platform for synthesizing toroidal dipoles.
- The presented methods enable the creation of novel electromagnetic states and functionalities.
- This research opens avenues for advanced metamaterials and quantum optical devices.
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