Dynamical control on helicity of electromagnetic waves by tunable metasurfaces.
Dynamical control on helicity of electromagnetic waves by tunable metasurfaces.
复制标题
可调谐超表面对电磁波螺旋度的动态控制
DOI：
10.1038/srep27503
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发表时间：
2016-06-08
影响因子：
4.6
通讯作者：
Zhou L
中科院分区：
文献类型：
--
作者：
Xu HX;Sun S;Tang S;Ma S;He Q;Wang GM;Cai T;Li HP;Zhou L
控制电磁波的偏振态是光学领域的一个基本问题，近年来引起了人们的广泛关注。然而，到目前为止实现的大多数设备要么体积太大，要么只有特定的功能。本文将理论与实验相结合，证明了以二极管为有源元件的可调谐超表面可以动态控制电磁波的反射相位，从而显示出前所未有的操纵入射圆极化（CP）电磁波螺旋度的能力。通过控制嵌入二极管上的偏置电压，我们证明了该器件可以在两种不同的状态下工作。在“开”状态下，超表面在两个独立的频段内充当螺旋转换器和螺旋杂化器，而在“关”状态下，它在超宽频段内充当螺旋保持器。我们的发现为实现与相位控制相关的功能可切换器件铺平了道路，例如频率可调的亚波长腔，异常反射器甚至全息图。
Manipulating the polarization states of electromagnetic (EM) waves, a fundamental issue in optics, attracted intensive attention recently. However, most of the devices realized so far are either too bulky in size, and/or are passive with only specific functionalities. Here we combine theory and experiment to demonstrate that, a tunable metasurface incorporating diodes as active elements can dynamically control the reflection phase of EM waves, and thus exhibits unprecedented capabilities to manipulate the helicity of incident circular-polarized (CP) EM wave. By controlling the bias voltages imparted on the embedded diodes, we demonstrate that the device can work in two distinct states. Whereas in the “On” state, the metasurface functions as a helicity convertor and a helicity hybridizer within two separate frequency bands, it behaves as a helicity keeper within an ultra-wide frequency band in the “Off” state. Our findings pave the way to realize functionality-switchable devices related to phase control, such as frequency-tunable subwavelength cavities, anomalous reflectors and even holograms.