2021/12/19 by David E. Fernandes, Fernandes, David E., Ricardo Pereira +7 · 1 citation
Computer Science · Engineering · Physics and Astronomy · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Neural Networks and Reservoir Computing #Optics (physics.optics) #Photonic Crystals and Applications #Photonic and Optical Devices
paper · pdf · doi:10.48550/arxiv.2112.13658
openalex publication_date 2021/12/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this article, it is experimentally verified that nonreciprocal photonic systems with a continuous translation symmetry may have an ill-defined topology. The topological classification of such systems is only feasible when the material response is regularized with a spatial-frequency cutoff. Here, we experimentally demonstrate that inserting a small air gap in between two materials may effectively imitate an idealized spatial cutoff that suppresses the nonreciprocal response for short wavelengths and regularizes the topology. Furthermore, it is experimentally verified that nonreciprocal systems with an ill-defined topology may be used to abruptly halt the energy flow in a unidirectional waveguide due to the violation of the bulk-edge correspondence. In particular, we report the formation of an energy sink that absorbs the incoming electromagnetic waves with a large field enhancement at the singularity.