All-silicon terahertz metasurfaces for multi-focus multiplexed polarization generation

Area of Science:

• Optics and Photonics
• Metamaterials
• Terahertz Technology

Background:

• Polarization multiplexing boosts communication capacity but is hindered by material limitations and complex device setups.
• Existing methods struggle to generate and control diverse polarization states simultaneously.

Purpose of the Study:

• To propose and demonstrate a new strategy for generating multiple polarization states using combined geometric and propagation phases in metasurfaces.
• To enable simultaneous generation of scalar and vector beams with precise wavefront control.

Main Methods:

• Design of two all-silicon terahertz metasurfaces utilizing spatially interleaved meta-atoms.
• Independent manipulation of phase and amplitude for different polarization states in transmission.
• Utilizing left-handed circularly polarized (LCP) illumination for beam generation.

Main Results:

• Demonstrated simultaneous generation of scalar (linearly and circularly polarized) and vector beams (VBs).
• Achieved independent phase and amplitude control for distinct polarization states.
• Successfully realized multi-polarization state focusing and longitudinal focusing of vortex beams with unique topological charges.

Conclusions:

• The proposed metasurface strategy overcomes material limitations for polarization multiplexing.
• This approach offers advanced terahertz polarization manipulation capabilities.
• Significant potential for next-generation communication systems and secure information transmission.