Simultaneous Circular Dichroism and Wavefront Manipulation with Generalized Pancharatnam-Berry Phase Metasurfaces

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Simultaneous circular dichroism and wavefront manipulation are crucial for advanced optical applications, driving miniaturization and integration.
• Existing structures with n-fold rotational symmetry (n ≥ 3) enhance circular dichroism but struggle with wavefront control due to isotropy.
• A need exists for novel nanostructures that enable both strong chiroptical responses and precise wavefront shaping.

Purpose of the Study:

• To propose and experimentally demonstrate a plasmonic metasurface capable of simultaneous circular dichroism and wavefront manipulation.
• To investigate the use of C3 Archimedes spiral nanostructures for achieving these dual optical functionalities.
• To explore potential applications in chiroptical spectroscopy, chiral imaging, and advanced optical device design.

Main Methods:

• Design and fabrication of a plasmonic metasurface composed of C3 Archimedes spiral nanostructures.
• Experimental characterization of the fabricated metadevices in the near-infrared regime.
• Analysis of circular dichroism arising from magnetic dipole-dipole resonance and meta-atom interactions.

Main Results:

• Achieved simultaneous circular dichroism (maximum value of ~0.62) and wavefront manipulation.
• Demonstrated the effectiveness of C3 Archimedes spiral nanostructures in inducing strong chiroptical effects.
• Successfully fabricated and characterized two proof-of-concept metadevices.

Conclusions:

• The proposed C3 Archimedes spiral plasmonic metasurface effectively enables simultaneous circular dichroism and wavefront control.
• This approach overcomes limitations of traditional isotropic structures for combined optical functionalities.
• The developed metadevices hold significant potential for applications in photodetection, chiroptical spectroscopy, and customized optical responses.