High-Sensitivity Detection of Chiro-Optical Effects in Single Nanoparticles by Four-Wave Mixing Interferometry.

Area of Science:

• Nanotechnology
• Plasmonics
• Chirality

Background:

• Measuring chirality in single nano-objects is challenging.
• Chiral nanoparticles have expanding applications in various fields.
• Conventional methods struggle with sensitivity for single-particle chirality detection.

Purpose of the Study:

• To develop a sensitive technique for detecting chiro-optical effects in single plasmonic nanoparticles.
• To quantify chirality at the single-particle level with high precision.
• To explore the potential of a novel microscopy method for chiral nanomaterial characterization.

Main Methods:

• Phase-sensitive polarization-resolved four-wave mixing interferometric microscopy.
• Fabrication of single chiral nanohelices using focused ion beam induced deposition.
• Analysis of particle polarizability in amplitude and phase for chirality detection.

Main Results:

• The technique successfully detected chiro-optical effects in single chiral nanohelices.
• Dissymmetry factors (gα) approaching unity were achieved for nanohelices.
• High dissymmetry factors, an order of magnitude greater than conventional methods, were observed in small gold nanoparticles.

Conclusions:

• The developed microscopy technique provides a sensitive and powerful tool for quantifying single-particle chiro-optical effects.
• The method surpasses conventional techniques in sensitivity for chiral nanomaterial analysis.
• This advancement is crucial for applications of chiral plasmonic nanoparticles in catalysis, metamaterials, and beyond.