Department of Electrical and Computer Engineering, Duke University, Box 90291, Durham, NC, 27708, USA.
Department of Physics, The University of California at San Diego, La Jolla, CA, 92093, USA.
Adv Mater. 2018 May;30(22):e1800278. doi: 10.1002/adma.201800278. Epub 2018 Apr 9.
Conventional dielectric metasurfaces achieve their properties through geometrical tuning and consequently are static. Although some unique properties are demonstrated, the usefulness for realistic applications is thus inherently limited. Here, control of the resonant eigenmodes supported by Huygens' metasurface (HMS) absorbers through optical excitation is proposed and demonstrated. An intensity transmission modulation depth of 99.93% is demonstrated at 1.03 THz, with an associated phase change of greater than π/2 rad. Coupled mode theory and S-parameter simulations are used to elucidate the mechanism underlying the dynamics of the metasurface and it is found that the tuning is primarily governed by modification of the magnetic dipole-like odd eigenmode, which both lifts the degeneracy, and eliminates critical coupling. The dynamic HMS demonstrates wide tunability and versatility which is not limited to the spectral range demonstrated, offering a new path for reconfigurable metasurface applications.
传统的介电质超表面通过几何调整来实现其特性，因此是静态的。尽管已经展示了一些独特的性质，但对于实际应用的实用性因此受到固有限制。在这里，通过光激发来控制由惠更斯超表面（HMS）吸收器支持的共振本征模式的方案被提出并得到了验证。在 1.03THz 处实现了 99.93%的强度透射调制深度，相关的相位变化大于π/2rad。采用耦合模理论和 S 参数模拟来阐明超表面动力学的机制，结果发现，调谐主要由类似磁偶极子的奇数本征模式的修改来控制，这既消除了简并，又消除了临界耦合。动态 HMS 具有广泛的可调谐性和多功能性，不仅限于所展示的光谱范围，为可重构超表面应用提供了新的途径。
