All-optically tunable electromagnetic chirality transfer

Detecting and controlling the chirality of matter play an essential role in exploring nature, providing previously unexplored avenues for matter discrimination and quantum manipulation. In such tasks, chiral probes are essential in defining or enhancing the chiral dichroism response. However, overlooking their influence on the symmetry of the medium hampers the ability to deterministically induce electromagnetic chirality. Here, we propose a simple yet versatile all-optical chirality transfer method to generate and manipulate the electromagnetic chirality of a neutral atomic medium. By inducing chirality-dependent dispersion in the atomic system, our method enables deterministic and tunable control of chirality transfer via a helical field. We theoretically analyze the mechanism of this optically induced symmetry breaking and experimentally demonstrate the helicity-dependent response of the medium. Our results show that the induced chirality can be effectively suppressed or enhanced, enabling deterministic electromagnetic enantioselection. This approach opens an efficient pathway for manipulating chiral symmetry breaking in light-matter interactions.