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Extraordinary surface voltage effect in the invisibility cloak with an active device inside.
Baile Zhang1, Hongsheng Chen, Bae-Ian Wu
1The Electromagnetics Academy at Zhejiang University, Zhejiang University, Hangzhou 310058, China.
Physical Review Letters
|March 21, 2008
Summary
This study establishes an electromagnetic field solution for a spherical invisibility cloak. It demonstrates how induced surface voltages prevent electromagnetic waves from escaping, preserving wave properties.
Area of Science:
- Electromagnetism
- Metamaterials
- Wave Optics
Background:
- Invisibility cloaking aims to control electromagnetic wave propagation.
- Active devices within cloaks can modify electromagnetic fields.
- Understanding boundary conditions is crucial for cloak functionality.
Purpose of the Study:
- To establish the electromagnetic field solution for a spherical invisibility cloak with an internal active device.
- To analyze the behavior of electromagnetic waves interacting with the cloak's boundaries.
- To investigate the physical interpretation of induced surface voltages.
Main Methods:
- Solving Maxwell's equations for a spherical geometry with specific boundary conditions.
- Analyzing the induction of extraordinary electric and magnetic surface voltages.
- Investigating the preservation of phase and polarization of incident waves.
Main Results:
- An electromagnetic field solution for the spherical cloak is established.
- Extraordinary surface voltages at the inner boundary prevent wave emission.
- Phase and handedness of polarized waves are preserved in reflections.
- Surface voltages are linked to auxiliary scalar potentials, gaining physical meaning.
Conclusions:
- The established solution validates the design principles for active spherical invisibility cloaks.
- The findings demonstrate a method for confining electromagnetic waves within a cloak.
- The physical interpretation of surface voltages provides insights into cloak operation.
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