Electromagnetic wave beam manipulator based on an all-dielectric THz coding metasurface

Area of Science:

• Metamaterials and Nanophotonics
• Terahertz (THz) Technology
• Electromagnetic Wave Manipulation

Background:

• Traditional metal-based metasurfaces suffer from significant internal electromagnetic loss in the THz band.
• Effective manipulation of terahertz waves is crucial for advanced applications in sensing, imaging, and communication.

Purpose of the Study:

• To propose and demonstrate an all-dielectric THz coding metasurface for electromagnetic wave control.
• To investigate the feasibility of using dielectric materials for low-loss THz wave manipulation.

Main Methods:

• Design of sub-wavelength coding units composed of a rectangular base and a cross dielectric column.
• Encoding achieved by altering the thickness of the dielectric column's X arm to control reflection phases.
• Theoretical calculations and full-wave numerical simulations to validate performance at 0.85 THz.

Main Results:

• Demonstrated 1- and 2-bit coding metasurfaces capable of modulating the number and direction of far-field reflection beams.
• Achieved agreement between theoretical predictions and simulation results for perpendicular incident electromagnetic waves.
• All-dielectric design exhibited low internal electromagnetic loss, outperforming metal-based counterparts.

Conclusions:

• The proposed all-dielectric THz coding metasurface effectively manipulates electromagnetic waves with low loss.
• The design offers flexibility in regulating reflected beams for applications like abnormal refraction and beam splitting in the THz band.
• All-dielectric materials provide a cost-effective and robust alternative for THz metasurface development.