Mu and epsilon near zero metamaterials for perfect coherence and new antenna designs.
Mu and epsilon near zero metamaterials for perfect coherence and new antenna designs.
复制标题
DOI：
10.1364/oe.22.009107
复制
发表时间：
2014-04
期刊：
影响因子：
3.8
通讯作者：
J. Yang;Y. Francescato;S. Maier;F. Mao;Ming Huang
中科院分区：
文献类型：
--
作者：
J. Yang;Y. Francescato;S. Maier;F. Mao;Ming Huang
波干涉是一种基本的物理现象。传统上，两个相同点源的相干效应仅在光路为整数个波长时才会发生。在本文中，我们证明 mu 和 epsilon 近零 (MENZ) 超材料可用于实现完美的相长和各向同性干涉。无论 MENZ 区域嵌入多少个点源，波前都会完美重叠。这转化为 MENZ 超材料内场的表观无限波长所实现的传统相干条件的完全放松。此外，我们还研究了 MENZ 区域的形状和大小等关键参数。我们证明，平面几何形状会产生相长干涉光束，作为一种强大的设计手段。我们还揭示了依赖深亚波长 MENZ 体积的重要性，因为较大的尺寸会增加阻抗，从而降低器件的输出功率。所提出的概念对于受电磁超材料最新发展启发的当前天线设计趋势具有重要意义。此外，完美的相干效应对功率组合器很有吸引力，特别是在光源昏暗的太赫兹区域，因为辐照强度与嵌入式光源数量的平方成正比。
Wave interference is a fundamental physical phenomenon. Traditionally, the coherent effect of two identical point sources only takes place when the optical path is an integer number of wavelengths. In this paper, we show that mu and epsilon near zero (MENZ) metamaterials can be used to realize a perfectly constructive and isotropic interference. No matter how many point sources are embedded in the MENZ region, the wavefronts overlap perfectly. This translates into a total relaxation of the conventional condition for coherence enabled by the apparent infinite wavelength of the fields within MENZ metamaterials. Furthermore, we investigate crucial parameters such as the shape and size of the MENZ region. We demonstrate that flat sided geometries give rise to constructive interference beams serving as a powerful design mean. We also reveal the importance of relying on deeply sub-wavelength MENZ volumes as larger sizes increase the impedance and therefore reduce the output power of the device. The proposed concepts bear significance for current trends in antenna design which are inspired by the recent developments of electromagnetic metamaterials. Moreover, the perfect coherence effect can be appealing for power combiners, especially in the terahertz where sources are dim, as the irradiation intensity scales with the square of the number of embedded sources.