Poincaré sphere trajectory encoding metasurfaces based on generalized Malus' law

Area of Science:

• Optics and Photonics
• Metasurfaces
• Information Encoding

Background:

• Light polarization is crucial for optical applications like displays and encryption.
• Current methods using Malus' law have limited encoding flexibility due to 1D projections.
• Metasurfaces offer potential for advanced optical functionalities.

Purpose of the Study:

• To propose a novel Poincaré sphere (PS) trajectory encoding approach using metasurfaces.
• To overcome the limitations of conventional 1D polarization encoding schemes.
• To enable versatile polarization image transformations and enhance encoding dimensionality.

Main Methods:

• Leveraging a generalized Malus' law for 2D projections between elliptical polarization states on the PS.
• Engineering PS trajectories using analytic functions or modulation grids.
• Utilizing metasurfaces to realize arbitrary polarization encodings.

Main Results:

• Demonstrated arbitrary polarization encodings by engineering PS trajectories.
• Achieved versatile polarization image transformations (histogram stretching, thresholding, encryption).
• Enabled these transformations within non-orthogonal PS loci.

Conclusions:

• The proposed PS trajectory encoding significantly expands polarization information dimensionality.
• Metasurfaces unlock new possibilities for polarization optics in classical and quantum regimes.
• This work paves the way for advanced optical information processing and security.