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Extinction symmetry for reciprocal objects and its implications on cloaking and scattering manipulation
Optics Letters
|July 1, 2014
Summary
Scattering cross sections are identical for opposite illumination directions for passive objects. Introducing absorption breaks this symmetry, enabling novel cloaking and scattering suppression designs.
Area of Science:
- Electromagnetics and Optics
- Wave Scattering Theory
Background:
- Understanding wave-matter interactions is crucial for designing advanced optical devices.
- Scattering properties of objects dictate their visibility and interaction with electromagnetic fields.
Purpose of the Study:
- To investigate the relationship between scattering cross sections under reversed illumination.
- To explore the implications of scattering symmetry for optical device design, including cloaking and scattering suppression.
Main Methods:
- Application of fundamental principles of Lorentz reciprocity.
- Utilizing the law of power conservation in electromagnetic theory.
- Analysis of extinction and scattering cross sections for arbitrarily shaped scatterers.
Main Results:
- Proved that extinction cross section is invariant under reversed illumination with identical polarization.
- Demonstrated that scattering cross sections are identical for lossless, passive objects under opposite excitations.
- Showed that absorption breaks scattering symmetry, leading to potential for large scattering asymmetries.
Conclusions:
- The inherent scattering symmetry of passive objects has significant implications for cloaking and scattering suppression.
- Introducing absorption provides a tunable mechanism to break scattering symmetry.
- Combining absorption with Fano interference offers a pathway to achieve large scattering asymmetries.
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