Zhou Chaobiao, Li Shiyu, Fan Menghui, Wang Xinfeng, Xu Yanli, Xu Weiwei, Xiao Shuyuan, Hu Mingzhe, Liu Jiangtao
Opt Express. 2020 Mar 30;28(7):9690-9701. doi: 10.1364/OE.389968.
Active optical metadevices have attracted growing interest for the use in nanophotonics owing to their flexible control of optics. In this work, by introducing the phase-changing material GeSbTe (GST), which exhibits remarkably different optical properties in different crystalline states, we investigate the active optical radiation manipulation of a resonant silicon metasurface. A designed double-nanodisk array supports a strong toroidal dipole excitation and an obvious electric dipole response. When GST is added, the toroidal response is suppressed, and the toroidal and electric dipoles exhibit pronounced destructive interference owing to the similarity of their far-field radiation patterns. When the crystallization ratio of GST is varied, the optical radiation strength and spectral position of the scattering minimum can be dynamically controlled. Our work provides a route to flexible optical radiation modulation using metasurfaces.
有源光学超构器件因其对光学的灵活控制而在纳米光子学中的应用引起了越来越多的关注。在这项工作中，通过引入在不同晶态下表现出显著不同光学性质的相变材料GeSbTe（GST），我们研究了谐振硅超表面的有源光辐射操控。设计的双纳米盘阵列支持强环形偶极子激发和明显的电偶极子响应。添加GST后，环形响应受到抑制，并且由于它们远场辐射模式的相似性，环形和电偶极子表现出明显的相消干涉。当GST的结晶率变化时，散射最小值的光辐射强度和光谱位置可以动态控制。我们的工作提供了一种利用超表面进行灵活光辐射调制的途径。
