Ultra-thin 2-bit anisotropic Huygens coding metasurface for terahertz wave manipulation

Area of Science:

• Electromagnetics and Optics
• Materials Science

Background:

• Metasurfaces offer advanced control over electromagnetic waves.
• Terahertz (THz) technology requires efficient wavefront manipulation tools.

Purpose of the Study:

• To design and demonstrate an ultrathin 2-bit anisotropic Huygens coding metasurface (AHCM).
• To achieve flexible manipulation of terahertz waves with low reflection and full phase coverage.
• To explore multifunctional applications, including use as a quarter-wave plate.

Main Methods:

• Designing bilayer metallic square-ring structures for meta-atoms.
• Analyzing polarized-dependent electric surface admittance and magnetic surface impedance.
• Exciting electric and magnetic resonances for broadband operation.
• Encoding meta-atoms with distinct binary sequences for wavefront control.

Main Results:

• The designed AHCM exhibits full phase coverage and significantly low reflection.
• Anomalous refraction of x- and y-polarized terahertz waves in opposite directions was achieved.
• The metasurface demonstrated functionality as a transmission-type quarter-wave plate.

Conclusions:

• The proposed ultrathin AHCM provides a novel platform for multifunctional terahertz wavefront manipulation.
• This work opens new avenues for advanced terahertz devices and applications.