Angle-selective chiral absorption induced by diffractive coupling in metasurfaces.

Area of Science:

• Plasmonics and Metamaterials
• Chiral Optics
• Nanophotonics

Background:

• Chiral metasurfaces are crucial for manipulating light polarization.
• Achieving tunable and efficient chiral absorption remains a challenge.
• Existing methods often lack broad spectral tunability or simplicity.

Purpose of the Study:

• To demonstrate a simple chiral metasurface for highly efficient and tunable chiral absorption.
• To explore the underlying mechanism of angle-selective chiral absorption.
• To highlight the potential of this metasurface for various chiral photonic applications.

Main Methods:

• Fabrication of a chiral metasurface using twisted metallic cut-wire arrays.
• Investigation of chiral absorption properties by varying the incidence angle.
• Excitation of surface plasmon resonance (SPR) through diffractive effects.

Main Results:

• The chiral metasurface achieved highly efficient and continuously tunable chiral absorption.
• Tunability was realized by simply scanning the incidence angle over a few degrees.
• Angle-selective chiral absorption was attributed to SPR excited by diffractive effects.

Conclusions:

• A simple chiral metasurface enables efficient, angle-tunable chiral absorption over a broad spectrum.
• This diffraction-assisted approach offers a straightforward strategy for dynamic chiral devices.
• Potential applications include on-chip chiral detectors, emitters, spectrometers, and lasers.