Enhancing Volumetric Optical Chirality through 2D-3D Structural Design Evolution.

Circular dichroism (CD) sensing plays a pivotal role in probing molecular chirality in biomedical sciences. However, engineering superchiral electromagnetic fields that can reliably amplify the faint signatures of chiral analytes remains profoundly challenging. Central to this difficulty is the need to balance two competing demands: maximizing the enhancement of chiral fields while maintaining a sufficient interaction volume for effective molecular interrogation. Here, we introduce a figure of merit (FOM) that captures the enhancement and spatial coverage of the superchiral fields. We examine the effects of helix-geometry evolution on the FOM. The optimized triple-strand helix markedly enhanced the analyte CD signal, yielding a FOM of 2.43 × 1010 nm3, which surpassed prior configurations by over an order of magnitude. Our findings provide a systematic design framework for 3D chiral structures for assessing their chiroptical sensing performance, particularly in scenarios involving clusters of randomly oriented small molecules or a large chiral molecule.