Terahertz wavefront engineering using a hard-coded metasurface


Noori A., Akyurek B., Demirhan Y., Ozyuzer L., Guven K., Altan H., ...More

Optical and Quantum Electronics, vol.55, no.8, 2023 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 55 Issue: 8
  • Publication Date: 2023
  • Doi Number: 10.1007/s11082-023-04955-x
  • Journal Name: Optical and Quantum Electronics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Keywords: Anomalous reflection, Coding metamaterials, Terahertz waves, Wavefront engineering
  • Middle East Technical University Affiliated: Yes

Abstract

During the past few years, coding metamaterials (MM) drew significant attention, where the far-field scattering/transmission pattern of the electromagnetic wave (particularly in the THz regime) can be encoded into a single or few-bit digitized phase-response of the metasurface, thereby enabling a full digital control. Single-bit MMs contain two types of unit cells where the phase becomes 0 and 1 (in units of Π), respectively. By arranging these unit cells into a 2D surface pattern, the THz wavefront can be shaped. In this work, a novel hard-coded metasurface was designed, fabricated, and experimentally investigated for multi-beam reflection of incident THz beam. The design employs stripe and checkerboard patterns of bilayer MM unit cells consisting of square gold patches with a polymer spacing layer from a gold backplane. Experimental and simulation results show that the incident wave in the 0.500–0.750 THz range can be reflected with > 95% efficiency in uniform amplitude and 1-bit coded phase. For the checkerboard metasurface pattern, the measured and analytically calculated reflection angle shows good agreement. The metasurface design is suitable for large-scale fabrication and can potentially be used as a template in the development of actively coded metasurfaces.