Hamiltonian Hopping for Efficient Chiral Mode Switching in Encircling Exceptional Points
Aodong Li, Jianji Dong, Jian Wang, Ziwei Cheng, John S. Ho, Dawei Zhang, Jing Wen, Xulin Zhang, C. T. Chan, Andrea Alù, Cheng‐Wei Qiu, Lin Chen
Abstract
Dynamically encircling exceptional points (EPs) can lead to chiral mode switching as the system parameters are varied along a path that encircles EP. However, conventional encircling protocols result in low transmittance due to path-dependent losses. Here, we present a paradigm to encircle EPs that includes fast Hamiltonian variations on the parameter boundaries, termed Hamiltonian hopping, enabling ultrahigh-efficiency chiral mode switching. This protocol avoids path-dependent loss and allows us to experimentally demonstrate nearly 90% efficiency at 1550 nm in the clockwise direction, overcoming a long-standing challenge of non-Hermitian optical systems and powering up new opportunities for EP physics.