Geometry-invariant resonant cavities.
Geometry-invariant resonant cavities.
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DOI：
10.1038/ncomms10989
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发表时间：
2016-03-24
影响因子：
16.6
通讯作者：
Engheta N
中科院分区：
文献类型：
--
作者：
Liberal I;Mahmoud AM;Engheta N
谐振腔是科学和技术各个学科的基本组成部分之一，从抽象的理论建模到日常生活设备都有许多应用。常规腔的本征频率是其几何形状的函数，因此，选择谐振腔的尺寸和形状以在特定频率下操作。在这里，我们从理论上证明了存在的几何不变的谐振腔，也就是说，谐振器的本征频率是不变的相对于其外部边界的几何变形。这种效应是通过利用零折射率超材料的不寻常特性来获得的，例如ε近零介质，其能够在无损极限中解耦时间和空间场变化。这类新的谐振器可能会激发替代的设计概念，它可能会导致第一代可变形谐振设备。 谐振腔是科学技术中无处不在的基石。在这里，Liberal等人通过利用零折射率超材料的不寻常特性，从理论上证明了谐振器的存在，其本征频率相对于其外部边界的几何变形是不变的。
Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modelling to everyday life devices. The eigenfrequencies of conventional cavities are a function of their geometry, and, thus, the size and shape of a resonant cavity is selected to operate at a specific frequency. Here we demonstrate theoretically the existence of geometry-invariant resonant cavities, that is, resonators whose eigenfrequencies are invariant with respect to geometrical deformations of their external boundaries. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, such as epsilon-near-zero media, which enable decoupling of the temporal and spatial field variations in the lossless limit. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices. Resonant cavities are a ubiquitous building block in science and technology. Here, Liberal et al. demonstrate theoretically the existence of resonators whose eigenfrequencies are invariant with respect to geometrical deformations of their external boundaries, by exploiting the unusual properties of zero-index metamaterials.