Multifunctional polarization selectivity in a Sb₂S₃-based dichroism metasurface.

Area of Science:

• Metasurfaces
• Nanophotonics
• Optical Engineering

Background:

• Multifunctional polarization selectivity is crucial for optical communications, sensing, and holography.
• Metasurfaces offer a powerful platform for manipulating light polarization.
• Quasi-bound states in the continuum (q-BICs) enable strong light-matter interactions.

Purpose of the Study:

• To realize multifunctional linear and circular polarization selectivity using q-BICs.
• To investigate a Sb2S3-based Z-shaped metasurface for polarization control.
• To demonstrate dynamic tunability of polarization properties.

Main Methods:

• Fabrication of a Sb2S3-based Z-shaped metasurface.
• Utilizing quasi-bound states in the continuum (q-BICs) for polarization control.
• Employing quantitative multipole decomposition and electromagnetic field analysis.

Main Results:

• Achieved near-unity and reversible circular dichroism (CD) and linear dichroism (LD).
• Demonstrated selective CD and LD by controlling azimuth angles (e.g., CD0° = -0.94, LD45° = 0.87, CD90° = 0.99).
• Confirmed polarization-selective excitation of magnetic dipole resonance.
• Showcased dynamic tuning of CD and LD by altering Sb2S3 phase.

Conclusions:

• The Sb2S3-based Z-shaped metasurface effectively achieves multifunctional polarization selectivity.
• The q-BIC-enabled mechanism provides strong polarization control and dynamic tunability.
• This work paves the way for advanced optical devices with tailored polarization responses.