Abstract-Dielectric resonator reflectarray as high-efficiency non-uniform terahertz metasurface

Daniel Headland, Eduardo Carrasco, Shruti Nirantar, Withawat Withayachumnankul, Philipp Gutruf, James Schwarz, Derek Abbott, Madhu Bhaskaran, Sharath Sriram, Julien Perruisseau-Carrier, and Christophe Fumeaux

ACS Photonics, Just Accepted Manuscript

DOI: 10.1021/acsphotonics.6b00102

Publication Date (Web): May 13, 2016

Copyright © 2016 American Chemical Society

http://pubs.acs.org/doi/abs/10.1021/acsphotonics.6b00102

Abstract

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 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, non-dispersive material for terahertz waves. The resonators operate around the resonance of 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-field.