Flexible control of transmitting terahertz beams based on multilayer encoding metasurfaces

Area of Science:

• Metamaterials and Metasurfaces
• Electromagnetic Wave Manipulation
• Digital Signal Processing

Background:

• Encoding metasurfaces bridge physical metamaterial properties with digital coding for novel signal processing.
• Metasurfaces offer control over electromagnetic wave properties, enabling phenomena like beam deflection.

Purpose of the Study:

• To demonstrate a method for manipulating terahertz (THz) beams using encoding metasurfaces.
• To achieve flexible and continuous control over the direction of transmitted THz beams with cross-polarization.

Main Methods:

• Designed multilayer metasurface structures to achieve a complete 2π transmission phase.
• Utilized different period sequence codes to determine deflection angles.
• Applied Fourier convolution principles for optimizing coding sequences and achieving pre-designed transmitted beams.

Main Results:

• Successfully manipulated a complete 2π transmission phase with high efficiency at the target frequency.
• Demonstrated the generation of anomalous single transmission beams with flexible and continuous control over arbitrary directions.
• Achieved cross-polarized transmission of normally incident terahertz beams to abnormal, arbitrary directions.

Conclusions:

• Fourier calculation offers an efficient method for optimizing metasurface coding to achieve desired beam characteristics.
• This digital approach provides a new perspective for metamaterial applications, combining electromagnetic wave operations with digital signal processing.
• The developed technique allows for precise, arbitrary steering of terahertz beams, advancing metasurface functionalities.