Active metasurface terahertz deflector with phase discontinuities

Area of Science:

• Optics and Photonics
• Metasurface Technology
• Terahertz (THz) Science

Background:

• Metasurfaces offer significant control over light beams, enabling novel functional components.
• Dynamic control techniques for metasurface properties are currently underdeveloped.
• Controlling anomalous diffraction in the terahertz regime remains a challenge.

Purpose of the Study:

• To present the first active wave deflector utilizing a metasurface with phase discontinuities.
• To demonstrate real-time control and amplitude manipulation of broadband anomalous diffraction in the terahertz regime.
• To introduce a novel approach for developing tunable metasurfaces.

Main Methods:

• Fabrication of an active metasurface using complementary C-shape split-ring resonator elements on a doped semiconductor substrate.
• Exploitation of the Schottky diode effect at the metal-semiconductor interface.
• Application of an external voltage bias to modify the semiconductor's conductivity and control terahertz wave intensity.

Main Results:

• Achieved efficient real-time amplitude manipulation of broadband anomalous diffraction in the terahertz regime.
• Demonstrated a modulation depth of up to 46% while maintaining broadband frequency responses and constant deflected angles.
• Observed modulation speeds of diffraction amplitude reaching several kilohertz.

Conclusions:

• The developed active metasurface provides efficient real-time control over terahertz wave amplitude and anomalous diffraction.
• The proposed voltage-controlled Schottky diode effect offers a viable method for dynamic metasurface tuning.
• This work opens new avenues for creating tunable metasurfaces for advanced terahertz applications.