Dual-state six-channel polarization multiplexing in reconfigurable metasurfaces

Area of Science:

• Photonics and Metamaterials
• Materials Science
• Optical Engineering

Background:

• Metasurfaces offer reconfigurable optical systems but struggle with multiple independent functions, especially under polarization multiplexing.
• Limited design flexibility in current metasurfaces hinders the integration of diverse functionalities within a single device.

Purpose of the Study:

• To present a metasurface design framework enabling the theoretical maximum of six independent phase modulation functions.
• To achieve simultaneous control over polarization states and phase-change material (PCM) crystallinity for enhanced functionality.

Main Methods:

• A pixel-extension strategy was employed, allowing individual nanofins in an amorphous state and reorganization into superpixels with distinct responses in a crystalline state.
• A forward filtering algorithm was developed to efficiently determine structural configurations under dual-state constraints.
• A progressive encoding strategy was introduced to embed optical information across material states by utilizing inter-state crosstalk.

Main Results:

• The proposed metasurface design framework successfully achieved six independent phase modulation functions.
• Demonstrated dynamically switchable multifocal metalenses and multichannel holography, confirming the approach's effectiveness.
• The platform offers high functional density and flexible control through simultaneous manipulation of polarization and PCM crystallinity.

Conclusions:

• The developed metasurface platform provides a compact and reconfigurable solution for advanced optical systems.
• This approach holds significant potential for applications in optical communication, information encryption, and adaptive display technologies.
• The framework overcomes previous limitations in design flexibility for multifunctional metasurfaces.