Mechano-tunable chiral metasurfaces via colloidal assembly

Area of Science:

• Photonics and Materials Science
• Nanotechnology and Optics

Background:

• Chiral metasurfaces offer dynamic control of circular polarization for photonic applications.
• Limited fabrication methods exist for chiral materials with tunable chiroptical responses in visible and near-infrared wavelengths.

Purpose of the Study:

• To develop a scalable bottom-up approach for fabricating chiral nanoparticle arrays.
• To achieve tunable chiroptical responses and enhance chiral sensing capabilities.

Main Methods:

• Constructing cross-stacked nanoparticle chain arrays using a scalable bottom-up approach.
• Utilizing in situ restacking and local mechanical compression for tuning circular dichroism.
• Investigating strain-induced reconfiguration for active polarization control.

Main Results:

• Achieved circular dichroism up to 11° in the fabricated nanoparticle arrays.
• Demonstrated tenfold enhanced sensitivity in chiral sensing due to accessible superchiral fields.
• Showcased full control over circular dichroism characteristics (sign, magnitude, spectral position).

Conclusions:

• The developed method provides a scalable route to chiral materials with tunable chiroptical properties.
• The layered design enhances chiral sensing sensitivity, making it suitable for detecting chiral analytes.
• Strain-induced reconfiguration offers potential for actively controlled pixel arrays and advanced polarization engineering.