Advanced Technology Research and Development Center, Mitsubishi Electric Corporation, Amagasaki, Hyogo 661-8661, Japan.
Department of Electronic Systems Engineering, The University of Shiga Prefecture, Hikone, Shiga 522-8533, Japan.
Phys Rev E. 2019 Jan;99(1-1):013204. doi: 10.1103/PhysRevE.99.013204.
Cloaking and scattering cancellation of electromagnetic waves have attracted much attention since they allow control of rf and light waves and are of scientific interest. The analytical results demonstrated in this paper reveal that plasmonic cloaking, which is one of the schemes for scattering cancellation, occurs in the vicinity of Tonks-Dattner resonances in the frequency domain, where resonances enhance wave scattering. This antiresonance-resonance pair for cloaking and scattering is cross-correlated by the symmetrical locations above and below the electron plasma frequency, respectively. However, the cloaking effect is almost independent of electron collisions with neutral particles, whereas scattering at resonance is fairly sensitive to them, leading to unclear resonance. An experimental verification of this analytical prediction is performed for the cloaking effect on working points passing through the cloaking condition and approaching resonance, which is dynamically controlled by changing the electron density. Numerical calculations based on a model configuration similar to the experimental setup confirm scattering cancellation and an increase in scattering as the points get close to the resonance condition. These results are direct evidence of scattering cancellation with a uniform epsilon-near-zero material and demonstrate the effectiveness of plasma as a cloaking material.
电磁波的隐身和散射消除自提出以来就引起了广泛关注，因为它们可以控制射频和光波，具有重要的科学意义。本文的分析结果表明，等离子体隐身是散射消除的一种方案，它发生在频域中的 Tonks-Dattner 共振附近，在该区域共振会增强波的散射。这种对隐身和散射的反共振-共振对通过电子等离子体频率上下的对称位置相互关联。然而，隐身效应几乎与电子与中性粒子的碰撞无关，而在共振处的散射对其非常敏感，导致共振不清晰。通过改变电子密度动态控制工作点穿过隐身条件并接近共振的实验验证了这种分析预测的隐身效应，数值计算基于与实验装置相似的模型配置，证实了散射消除和散射随着工作点接近共振条件而增加。这些结果直接证明了具有均匀的近零介电常数材料的散射消除，并展示了等离子体作为隐身材料的有效性。
