Structured Optical Fields Reveal Nanoscale Chiral Light-Matter Interactions Governed by Optical Chirality
arXiv:2607.12435
The authors create an optical field with spatially varying optical chirality and demonstrate that a single chiral nanoparticle’s response follows this modulation, confirming that optical chirality governs nanoscale chiral light‑matter interactions.
Abstract
Optical chirality has been proposed as the local electromagnetic quantity governing chiral light-matter interactions, yet in conventional circularly polarized fields its magnitude is locked to the electric energy density, obscuring its independent role. Here we create a structured optical field in which optical chirality arises spatially in magnitude and sign while the electric energy density remains nearly uniform. A single chiral nanoparticle exhibits a differential response that follows this spatial variation, whereas no modulation is observed for an achiral nanoparticle, providing direct experimental evidence that optical chirality governs nanoscale chiral light-matter interactions. Measurements of wavelength-dependent optical rotation further provide an experimental estimate of the chiral polarizability, predicting a chiral gradient force of approximately 100 fN and a one-dimensional trapping potential exceeding the thermal energy at room temperature under optimized aqueous trapping conditions.
19 pages, 3 figures