Author Affiliations
Abstract
1 School of Physics and Optoelectronics, South China University of Technology, Guangzhou 510640, China
2 School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, China
We have studied a switchable hyperbolic metamaterial composed of a graphene–dielectric periodic structure. By tuning the chemical potential of all graphene sheets simultaneously, the isofrequency curve can switch between an ellipse and a hyperbola conveniently. In particular, a special hyperbolic isofrequency curve with its asymptote perpendicular to the interface is obtained and used to realize the zero reflection effect. Furthermore, a zero-reflection-based optical switch working in the terahertz spectrum is demonstrated. Its bandwidth can be efficiently adjusted by geometric parameters such as permittivity and period. Such an optical switch possesses the merits of low loss, high transmittance contrast, high response speed, compact size, high tolerance of chemical potential, and having all incident angles (0°–90°) simultaneously. Such an optical switch holds great potential in many fields, such as data storage, beam steering, and integrated photonic circuits.
Photonics Research
2019, 7(3): 03000318
华南理工大学物理与光电学院, 广东 广州 510640
研究了具有二重旋转对称性的椭圆介质柱光子晶体的宽带全角准直色散特性及其在分束器方面的应用。利用平面波展开法计算其色散关系，发现该类结构的TE 偏振模式在较宽的带宽内存在跨越整个第一布里渊区的平直等频线，利用这些平直等频线实现了宽带全角超准直光传输。在此基础上设计了一种Y 型能量分束器，时域有限差分(FDTD)仿真结果表明，该分束器对内置二维点光源和高斯光源均具有很好的分束性能。以上研究在光子器件集成、定向耦合等领域具有潜在的应用价值。
材料 光子晶体 对称性 超准直效应 能量分束器 光学学报
2015, 35(11): 1116002
