Awan Z A, Seetharamdoo Divitha
Appl Opt. 2020 Jul 1;59(19):5670-5679. doi: 10.1364/AO.392709.
An analysis of the scattering characteristics of a chiral sphere covered with a metasurface is presented. The electromagnetic fields inside and outside of a metasurface covered chiral sphere are expanded in terms of spherical vector wave functions. The influences of chirality and surface impedance of a metasurface upon the scattering cross section are investigated. It is seen that a specific type of metasurface can be used to significantly enhance and diminish the back scattering cross section from a chiral sphere having a fixed value of chirality but different radii. It is also observed that a chiral sphere having chirality close to unity apparently cannot be cloaked using a lossless metasurface as compared to a dielectric sphere, both having the same electromagnetic and geometrical parameters. A comparative study of the scattering characteristics of metasurface covered realistic chiral and low-loss Teflon dielectric spheres is developed. It is found that a metasurface covered realistic chiral sphere can be used to significantly reduce the scattering as compared to scattering from a metasurface covered Teflon sphere at a specific angle, provided that both spheres have the same radii and surface reactance.
本文对覆盖有超表面的手性球体的散射特性进行了分析。覆盖有超表面的手性球体内外的电磁场用球矢量波函数展开。研究了超表面的手性和表面阻抗对散射截面的影响。可以看出，对于具有固定手性值但半径不同的手性球体，特定类型的超表面可用于显著增强和减小其背向散射截面。还观察到，与具有相同电磁和几何参数的介质球体相比，手性接近1的手性球体显然不能用无损超表面实现隐身。对覆盖有超表面的实际手性球体和低损耗聚四氟乙烯介质球体的散射特性进行了对比研究。结果发现，在特定角度下，与覆盖有超表面的聚四氟乙烯球体的散射相比，覆盖有超表面的实际手性球体可用于显著降低散射，前提是两个球体具有相同的半径和表面电抗。
