Multi-state Chiral Switching Through Adiabaticity Control in Encircling Exceptional Points

TL;DR

This paper demonstrates a novel method for achieving chiral switching among multiple eigenstates in multi-state systems by controlling adiabaticity during encircling of exceptional points, with experimental validation in optical modes.

Contribution

It introduces a new approach to multi-state chiral switching using adiabaticity control, enabling non-crosstalk eigenstate evolution in complex topologies.

Findings

Experimental demonstration of chiral switching in a four-state optical system.

Theoretical extension of the approach to higher-order multi-state systems.

Potential for developing multiplexed photonic devices based on chiral dynamics.

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 been explored, associated with more complex topologies supporting a larger number of exceptional points, but chiral switching among multiple eigenstates has remained elusive in experiments. Here, we overcome this challenge by dividing the eigenstate space into multiple subspaces by controlling the adiabaticity. The eigenstates in different subspaces can evolve without crosstalk, and chiral switching occurs as the eigenstates within each subspace are subject to a non-adiabatic transition while they encircle exceptional points. We experimentally demonstrate this phenomenon by reporting chiral switching for two groups of optical modes at telecom wavelengths in a four-state optical system, and theoretically demonstrate that our approach can be extended to higher-order systems. Our 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.