On-demand multiplexed vortex beams for terahertz polarization detection based on metasurfaces.

Area of Science:

• Optics and Photonics
• Materials Science
• Electromagnetism

Background:

• Precise polarization measurement is vital for light-matter interactions and scientific applications.
• Conventional terahertz (THz) polarization detection methods are complex and limited.
• Metasurfaces combined with inhomogeneous vector vortex beams (VVBs) offer a promising integrated solution.

Purpose of the Study:

• To present a general design strategy for spin-multiplexing all-silicon metasurfaces for THz polarization detection.
• To demonstrate the capability of these metasurfaces in visualizing and reconstructing THz polarization states.
• To establish a visualized parametric model for analyzing polarization evolution.

Main Methods:

• Designing all-silicon metasurfaces using high aspect ratio building blocks for VVB generation.
• Utilizing a THz near-field scanning system to evaluate polarization reconstruction.
• Employing dynamically varying polarization as an illumination method for snapshot analysis.

Main Results:

• Demonstrated a metasurface capable of generating VVBs with tight focusing.
• Successfully reconstructed incident THz polarization states from the longitudinal component.
• Established a visualized parametric model for analyzing polarization evolution in a single snapshot.

Conclusions:

• The developed metasurface strategy enables efficient and visualized THz polarization detection.
• This approach facilitates the creation of ultra-compact THz polarization detection devices.
• Potential applications include remote sensing, high-resolution imaging, and communications.