Observation of Chiral Symmetry Breaking in Toroidal Vortices of Light

In this Letter, we explore the intersection of chirality and recently discovered toroidal spatiotemporal optical vortices (STOVs). We introduce ``photonic conchs'' theoretically as a new type of toroidal-like state exhibiting geometrical chirality, and experimentally observe these wave packets with controllable topological charges. Unlike toroidal STOVs, photonic conchs exhibit unique chirality-related dynamical evolution in free space and possess an orbital angular momentum correlated with all the dimensions of space-time. This research deepens our understanding of toroidal light states and potentially advances various fields by unveiling similar wave phenomena in a broader scope of physics systems, including acoustics and electronics.