Nanoconfinement‐Induced Second‐Harmonic Circular Dichroism via Chirality–Ferroelectric Coupling

ABSTRACT Achieving robust circularly polarized nonlinear optical responses in purely organic systems is fundamentally limited by the weak contribution of magnetic‐dipole‐related optical transitions. Here, we report a strategy to introduce pronounced circularly polarized nonlinear optical functionality through nanoconfined chirality–ferroelectric coupling. By infiltrating a ferroelectric nematic liquid crystal into a three‐dimensional chiral nanoporous scaffold, we promote symmetry breaking that facilitates electric–magnetic dipole interference. This coupling gives rise to pronounced nanoconfinement‐induced second‐harmonic generation circular dichroism (SHG‐CD), with an asymmetry factor |gSHG‐CD| of approximately 1.1. Systematic polarization‐resolved analysis suggests the emergence of an additional magnetic‐dipole‐associated nonlinear contribution that is negligible in the pristine ferroelectric nematic phase. The observed SHG‐CD response is consistent with multipolar interference effects arising from nanoconfined chirality–ferroelectric coupling. Beyond the specific system studied here, our results demonstrate that nanoconfinement provides a useful platform for engineering nonlinear chiroptical responses in organic materials. These findings offer new insights into chirality–ferroelectric coupling and suggest potential opportunities for polarization‐sensitive nonlinear photonic functionalities, including chiral imaging, polarization sensing, and frequency‐conversion applications.