Multi‐State Chiral Switching Through Adiabaticity Control in Encircling Exceptional Points

Abstract Dynamic encircling of exceptional points has attracted significant interest in recent years, as it can facilitate chiral transmission selectivity due to a nontrivial eigenstate evolution. Recently, multi‐state systems have garnered considerable attention due to their complex topologies, which support a larger number of exceptional points. However, the realization of chiral switching among arbitrary multiple eigenstates has remained restricted and incomplete. Here, this challenge is overcome by dividing the eigenstate space into multiple subspaces by controlling the adiabaticity. The eigenstates in different subspaces can evolve into each other, and chiral switching occurs as the eigenstates within each subspace are subject to a non‐adiabatic transition while they encircle exceptional points. This phenomenon is experimentally demonstrated by reporting chiral switching for two groups of optical modes at telecom wavelengths in a four‐state optical system, and theoretically demonstrates that this approach can be extended to arbitrary grouping of states in higher‐order systems. These findings pave new avenues for studying chiral dynamics based on exceptional‐point physics in multi‐state systems, and offer opportunities to develop multiplexed photonic devices.