Graphene-enabled electrically controlled terahertz meta-lens
Metasurfaces have become a new photonic structure for providing potential applications to develop integrated devices with small thickness, because they can introduce an abrupt phase change by arrays of scatterers. To be applied more widely, active metasurface devices are highly desired. Here, a tunable terahertz meta-lens whose focal length is able to be electrically tuned by ～4.45λ is demonstrated experimentally. The lens consists of a metallic metasurface and a monolayer graphene. Due to the dependence of the abrupt phase change of the metasurface on the graphene chemical potential, which can be modulated using an applied gate voltage, the focal length is changed from 10.46 to 12.24 mm when the gate voltage increases from 0 to 2.0 V. Experimental results are in good agreement with the theoretical hypothesis. This type of electrically controlled meta-lens could widen the application of terahertz technology.
基金项目：National Key R&D Program of China (2017YFB1002900); 973 Program of China (2013CBA01702); National Natural Science Foundation of China (NSFC)10.13039/501100001809 (11404224, 1174243, 11774246, 61405012, 61420106014); Excellent Young Scholars Research Fund of Beijing Institute of Technology (BIT).
Bin Hu：Beijing Engineering Research Center for Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
Zongduo Huang：Beijing Engineering Research Center for Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
Hongyu Guan：Beijing Engineering Research Center for Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
Heting Li：Beijing Key Laboratory for Metamaterials and Devices, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, and Beijing Advanced Innovation Center for Imaging Technology, Department of Physics, Capital Normal University, Beijing 100048, China
Xinke Wang：Beijing Key Laboratory for Metamaterials and Devices, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, and Beijing Advanced Innovation Center for Imaging Technology, Department of Physics, Capital Normal University, Beijing 100048, China
Yan Zhang：Beijing Key Laboratory for Metamaterials and Devices, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, and Beijing Advanced Innovation Center for Imaging Technology, Department of Physics, Capital Normal University, Beijing 100048, Chinae-mail: email@example.com
Hongxing Yin：Micro and Nanotechnology Research Center, School of Physics, Beijing Institute of Technology, Beijing 100081, China
Xiaolu Xiong：Micro and Nanotechnology Research Center, School of Physics, Beijing Institute of Technology, Beijing 100081, China
Juan Liu：Beijing Engineering Research Center for Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
Yongtian Wang：Beijing Engineering Research Center for Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
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Weiguang Liu, Bin Hu, Zongduo Huang, Hongyu Guan, Heting Li, Xinke Wang, Yan Zhang, Hongxing Yin, Xiaolu Xiong, Juan Liu, and Yongtian Wang, "Graphene-enabled electrically controlled terahertz meta-lens," Photonics Research 6(7), 703-708 (2018)