2025/01/14 by Dongyang Yan, Yan, Dongyang, Alexander S. Shalin +15 · 2 citations
Mathematics · Physics and Astronomy · #Applied Physics (physics.app-ph) #Applied mathematics #Computer science #Economics #FOS: Physical sciences #First order #Hermitian matrix #Index (typography) #Mathematical physics #Mathematics #Nonlinear Waves and Solitons #Optics (physics.optics) #Order (exchange) #Philosophy #Physics #Pure mathematics #Quantum Mechanics and Non-Hermitian Physics #Quantum mechanics #Statistical physics #Zero (linguistics) #Zero order #Zero-point energy
paper · pdf · doi:10.48550/arxiv.2501.07974
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2025/01/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Higher-order exceptional points (EPs) in optical structures enable ultra-sensitive responses to perturbations. However, previous investigations on higher-order EPs have predominantly focused on coupled systems, leaving their fundamental physics in open scattering systems largely unexplored. Here, we harness wave interference to realize higher-order EPs in non-Hermitian zero-index materials connected to multiple open channels. Specifically, we show that a three-channel model can give rise to three interesting types of third-order EPs: lasing EP, reflecting EP, and absorbing EP. Notably, near the third-order absorbing EP, we show ultrasensitivity -- a drastic change in output power in response to perturbations at the operating frequency -- in a purely lossy system. These findings pave the way for achieving higher-order and even arbitrary-order EPs in open scattering systems, offering significant potential for advanced sensing applications.