Continuous-Spectrum-Polarization Recombinant Optical Encryption with a Dielectric Metasurface

Area of Science:

• Optics and Photonics
• Metamaterials and Metasurfaces
• Information Security

Background:

• Metasurfaces offer multifunctional design via Jones matrices with eight degrees of freedom (DoFs).
• Extending DoFs into the spectral dimension theoretically enhances encryption capabilities.
• Current limitations include meta-atom topology and spectral responses hindering continuous polarization control over wavelength.

Purpose of the Study:

• To develop a forward evolution strategy for mapping dispersion Jones matrix solutions to meta-atom spectral responses.
• To enable arbitrary conjugate polarization channel reconstruction across a continuous spectrum.
• To demonstrate a silicon metadevice for secure optical information encryption and transmission.

Main Methods:

• Utilized a forward evolution strategy to establish mapping relationships between dispersion Jones matrix solutions and meta-atom spectral responses.
• Employed the eigenvector transformation method for reconstructing polarization channels.
• Fabricated and characterized a silicon metadevice for experimental validation.

Main Results:

• Successfully reconstructed arbitrary conjugate polarization channels over a continuous spectrum.
• Demonstrated a significant increase in information capacity (2^10) through combined polarization and wavelength control.
• Achieved high polarization contrasts (>94%) for conjugate polarization conversion across the 3-4 µm wavelength range.

Conclusions:

• The proposed approach enables precise control over polarization evolution across the spectrum, overcoming previous limitations.
• The developed silicon metadevice proves effective for high-capacity optical information encryption.
• This methodology is expected to advance secure optical and quantum information technologies.