Tunable Chiral Plasmonic Activities Enabled via Stimuli Responsive Micro-Origami.

Area of Science:

• Plasmonics
• Chiral Metamaterials
• Nanotechnology

Background:

• Chiral plasmonic nanomaterials offer unique optical responses for photonic and biomedical uses.
• Fabricating 3D chiral micro-constructs with tunable chiroptical properties remains a challenge, especially in the visible-near-infrared (vis-NIR) range.

Purpose of the Study:

• To construct 3D plasmonic chiral structures using a micro-origami approach.
• To achieve readily modulated chiroptical properties, including ellipticity, mode frequency, and switchable handedness.

Main Methods:

• Utilized self-rolling of gold nanosphere (AuNS)-decorated polymeric micro-sheets to create 3D structures.
• Employed polydimethylsiloxane-wrinkle assisted assembly for ordered linear AuNS chain formation on 2D sheets.
• Transformed 2D AuNS chains into 3D helices by rolling sheets into micro-tubules.

Main Results:

• Constructed 3D plasmonic chiral structures exhibiting strong chiroptical responses in the vis-NIR range.
• Achieved high circular dichroism (CD) values up to hundreds of millidegrees.
• Demonstrated active modulation of CD peak position and sign by controlling AuNS chain orientation.

Conclusions:

• The micro-origami strategy successfully integrates 2D assembly with 3D chiral structure fabrication.
• This method provides an effective route for constructing chiral plasmonic structures with tunable chiroptical effects using responsive polymers.