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Cylindrical invisibility cloak with simplified material parameters is inherently visible
Min Yan1, Zhichao Ruan, Min Qiu
1Department of Microelectronics and Applied Physics, Royal Institute of Technology, Electrum 229, 16440 Kista, Sweden.
Physical Review Letters
|February 1, 2008
Summary
Simplified invisibility cloaks allow the zeroth-order cylindrical wave to pass through, rendering objects visible. While higher-order waves are cloaked, finite scattering remains a challenge for these simplified designs.
Area of Science:
- Electromagnetism
- Metamaterials
- Optics
Background:
- The concept of perfect invisibility cloaks for electromagnetic illumination was proposed.
- Experimental and theoretical cylindrical cloaks have employed simplified material parameters for easier fabrication and to avoid infinite optical constants.
Purpose of the Study:
- To investigate the electromagnetic wave propagation through cylindrical invisibility cloaks with simplified material parameters.
- To determine the visibility of objects cloaked with simplified metamaterials.
Main Methods:
- Numerical simulations were employed to analyze wave propagation.
- The behavior of zeroth-order and high-order cylindrical waves was examined.
Main Results:
- Cylindrical cloaks with simplified material parameters allow the zeroth-order cylindrical wave to pass unimpeded, making the object visible.
- The simplified cloak exhibits some properties of ideal cloaks for high-order cylindrical waves, but finite scattering occurs.
Conclusions:
- Simplified material parameters in cylindrical cloaks lead to inherent visibility due to the passage of the zeroth-order wave.
- While partially effective for higher-order waves, simplified cloaks are not perfectly invisible due to residual scattering.
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