Asadchy V S, Ra'di Y, Vehmas J, Tretyakov S A
Department of Radio Science and Engineering, Aalto University, P.O. Box 13000, FI-00076 Aalto, Finland.
Department of General Physics, Francisk Skorina Gomel State University, 246019 Gomel, Belarus.
Phys Rev Lett. 2015 Mar 6;114(9):095503. doi: 10.1103/PhysRevLett.114.095503.
Conventional mirrors obey the simple reflection law that a plane wave is reflected as a plane wave, at the same angle. To engineer spatial distributions of fields reflected from a mirror, one can either shape the reflector or position some phase-correcting elements on top of a mirror surface. Here we show, both theoretically and experimentally, that full-power reflection with general control over the reflected wave phase is possible with a single-layer array of deeply subwavelength inclusions. These proposed artificial surfaces, metamirrors, provide various functions of shaped or nonuniform reflectors without utilizing any mirror. This can be achieved only if the forward and backward scattering of the inclusions in the array can be engineered independently, and we prove that it is possible using electrically and magnetically polarizable inclusions. The proposed subwavelength inclusions possess desired reflecting properties at the operational frequency band, while at other frequencies the array is practically transparent. The metamirror concept leads to a variety of applications over the entire electromagnetic spectrum, such as optically transparent focusing antennas for satellites, multifrequency reflector antennas for radio astronomy, low-profile conformal antennas for telecommunications, and nanoreflectarray antennas for integrated optics.
传统镜子遵循简单的反射定律，即平面波以相同角度被反射为平面波。为了设计从镜子反射的场的空间分布，人们可以塑造反射器的形状，或者在镜面上放置一些相位校正元件。在这里，我们通过理论和实验表明，使用单层深亚波长内含物阵列可以实现对反射波相位进行一般控制的全功率反射。这些提出的人工表面，即超表面镜子，无需使用任何镜子就能提供各种形状或非均匀反射器的功能。只有当阵列中内含物的前向和后向散射能够独立设计时才能实现这一点，并且我们证明使用电和磁可极化内含物是可行的。所提出的亚波长内含物在工作频段具有所需的反射特性，而在其他频率下，该阵列实际上是透明的。超表面镜子的概念在整个电磁频谱上有多种应用，例如用于卫星的光学透明聚焦天线、用于射电天文学的多频反射器天线、用于电信的低剖面共形天线以及用于集成光学的纳米反射阵列天线。
