Huang Yijia, Xiao Tianxiao, Xie Zhengwei, Zheng Jie, Su Yarong, Chen Weidong, Liu Ke, Tang Mingjun, Zhu Jianqi, Müller-Buschbaum Peter, Li Ling
Laboratory of Micro-Nano Optics, College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610101, P. R. China.
Physik-Department, Lehrstuhl Für Funktionelle Materialien, Technische Universität München, James-Franck-Straße 1, Garching 85748, Germany.
ACS Appl Mater Interfaces. 2021 Sep 29;13(38):45890-45897. doi: 10.1021/acsami.1c14204. Epub 2021 Sep 14.
Compared with conventional mirrors that behave as isotropic electromagnetic (EM) reflectors, metamirrors composed of periodically aligned artificial meta-atoms exhibit increased degrees of freedom for EM manipulations. However, the functionality of most metamirrors is fixed by design, and how to achieve active EM control is still elusive. Here, we propose a multistate metamirror based on the nonvolatile phase change material GeSbTe (GST) with four distinct functionalities that can be realized in the infrared region by exploiting the temperature-activated phase transition. When varying the crystallinity of GST, the metamirror has the capability to perform as a right-handed circular polarization chiral mirror, a narrowband achiral mirror, a left-handed circular polarization chiral mirror, or a broadband achiral mirror, respectively. The inner physics is further explained by the construction or cancellation of extrinsic two-dimensional chirality. As a proof of concept, experimental verification is carried out and the measured results agree well with their simulated counterparts. Such a multifunctional tunable metamirror could address a wide range of applications from sensing and spectroscopy to analytical chemistry and imaging.
与作为各向同性电磁（EM）反射器的传统镜子相比，由周期性排列的人工元原子组成的超表面镜子在电磁操纵方面展现出了更高的自由度。然而，大多数超表面镜子的功能在设计时就已固定，如何实现主动电磁控制仍然难以捉摸。在此，我们提出了一种基于非易失性相变材料锗锑碲（GST）的多态超表面镜子，它具有四种不同的功能，通过利用温度激活的相变，可在红外区域实现这些功能。当改变GST的结晶度时，该超表面镜子能够分别表现为右旋圆偏振手性镜、窄带非手性镜、左旋圆偏振手性镜或宽带非手性镜。内在物理机制可通过外在二维手性的构建或消除进一步解释。作为概念验证，我们进行了实验验证，测量结果与模拟结果吻合良好。这种多功能可调谐超表面镜子可应用于从传感、光谱学到分析化学和成像等广泛领域。
