Robust terahertz polarization analysis based on a unit-scale polarization-multiplexed metasurface.

Area of Science:

• Optics and Photonics
• Materials Science
• Spectroscopy

Background:

• Terahertz (THz) band polarization analysis is vital for material sensing and imaging due to its rich information content.
• Existing THz polarization analysis methods face challenges like component complexity, non-uniformity sensitivity, and intricate data processing.

Purpose of the Study:

• To develop a simplified and robust method for THz polarization analysis.
• To overcome the limitations of current polarization analysis techniques in the THz frequency range.

Main Methods:

• A single polarization-multiplexed metasurface was designed to independently focus four distinct polarization states (x, y, 45°, and left-handed circular) into separate spots.
• A calibrated measurement matrix was established to create a linear mapping between the intensities of these focused spots and Stokes parameters.
• Precise Jones matrix engineering and meta-atom polarization multiplexing were employed for accurate polarization state reconstruction.

Main Results:

• The proposed method establishes a linear relationship between spot intensities and Stokes parameters.
• Arbitrary polarization states in the terahertz band are accurately reconstructed.
• The technique demonstrates resilience to illumination non-uniformity, a common issue in optical systems.

Conclusions:

• The single metasurface approach offers a significant advancement for terahertz polarization analysis.
• This method provides a promising platform for developing advanced THz sensing and imaging applications.
• The technique enhances accuracy and robustness compared to conventional methods.