† School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA 5005, Australia
‡ École Polytechnique Fédérale de Lausanne, EPFL, 1015 Lausanne, Switzerland
¶ Foundation for Research on Information Technologies in Society, IT’IS, 8004 Zürich, Switzerland
§Functional Materials and Microsystems Research Group and ∥MicroNano Research Facility, RMIT University, Melbourne, Victoria 3000, Australia
⊥ Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
ACS Photonics, Article ASAP
DOI: 10.1021/acsphotonics.6b00102
Publication Date (Web): May 13, 2016
Copyright © 2016 American Chemical Society
*E-mail: daniel.headland@adelaide.edu.au.
Advances in terahertz technology rely on the combination of novel materials and designs. As new devices are demonstrated to address the terahertz gap, the ability to perform high-efficiency beam control will be integral to making terahertz radiation a practical technology. Here, we use a metasurface composed of nonuniform dielectric resonator antennas on a ground plane to achieve efficient beam focusing at 1 THz. The dielectric resonators are made of high-resistivity silicon, which is a low-loss, nondispersive material for terahertz waves. The resonators operate around the resonance of the displacement current in the silicon, which is crucial to attaining high efficiency. The reflectarray’s capacity to focus terahertz radiation is experimentally verified, and hence by the principle of antenna reciprocity, it can also be employed as a terahertz collimator. The demonstrated device can therefore be deployed for high-gain terahertz antennas. Further measurements show that the loss of the reflectarray is negligible, which confirms the high efficiency of the dielectric resonators. This finding will enable the design of efficient flat-profile terahertz reflectarrays and metasurfaces to serve arbitrary beam control requirements in the near and far fields.
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