Active circular dichroism coding meta-mirror for flexible beam-forming and dynamic amplitude control

Area of Science:

• Optics and Photonics
• Metamaterials Science
• Nanotechnology

Background:

• Chiral metasurfaces offer enhanced chiroptical responses beyond natural materials.
• Passive metasurfaces lack dynamic control, limiting engineering applications.
• Active elements are needed for real-time manipulation of metasurface properties.

Purpose of the Study:

• To propose a dynamic meta-mirror for controlled scattering modulation.
• To achieve tunable chiroptical responses using active elements.
• To demonstrate wave manipulation in a coded manner.

Main Methods:

• Design of a circular dichroism meta-mirror using Archimedean spiral meta-atoms.
• Integration of active elements for bias voltage control.
• Application of the Pancharatnam-Berry phase principle for wave tailoring.

Main Results:

• Smooth control over scattered reflection amplitude for a specific spin state.
• Minimal influence on the orthogonal spin state.
• Experimental verification using a 1-bit checkerboard meta-mirror producing a four-beam scattering pattern.

Conclusions:

• The proposed active chiral metasurface enables dynamic scattering modulation.
• This technology facilitates tunable wave manipulation for specific spin states.
• Potential applications include spin-sensitive systems and adaptive camouflage.