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

In the terahertz band corresponding to molecular vibration-rotation transitions, polarization encodes rich material information, rendering polarization analysis crucial for sensing and imaging. To overcome limitations of existing methods, including reliance on multiple components, susceptibility to non-uniformity, and complex polarization information extraction processes, we propose a new method, to the best of our knowledge, for polarization analysis through a single polarization-multiplexed metasurface. By independently focusing x-, y-, 45-, and left-handed circular polarization into four spots, a linear mapping between the spot intensities and Stokes parameters is established via a calibrated measurement matrix. Leveraging precise Jones matrix engineering and wavelength-scale meta-atom polarization multiplexing, arbitrary polarization states are accurately reconstructed with resilience to illumination non-uniformity. This method holds significant promise for terahertz polarization analysis and imaging applications.