Nanoscale Helical Optical Force for Determining Crystal Chirality

Abstract

AbstractThe deterministic control of material chirality has been a sought‐after goal. As light possesses intrinsic chirality, light‐matter interactions offer promising avenues for achieving non‐contact, enantioselective optical induction, assembly, or sorting of chiral entities. However, experimental validations are confined to the microscale due to the limited strength of asymmetrical interactions within sub‐diffraction limit ranges. In this study, a novel approach is presented to facilitate chirality modulation through chiral crystallization using a helical optical force field originating from localized nanogap surface plasmon resonance. The force field emerges near a gold trimer nanogap and is propelled by linear and angular momentum transfer from the incident light to the resonant nanogap plasmon. By employing Gaussian and Laguerre–Gaussian incident laser beams, notable enantioselectivity is achieved through low‐power plasmon‐induced chiral crystallization of an organic compound–ethylenediamine sulfate. The findings provide new insights into chirality transmission orchestrated by the exchange of linear and angular momentum between light and nanomaterials.