Coherence-independent non-Hermitian topological filters
Phys. Rev. A 112, 063519 – Published 9 December, 2025
DOI: https://doi.org/10.1103/ylwg-dh7t
Abstract
We introduce a non-Hermitian photonic filter that harnesses dissipation to selectively isolate a desired topological state. In science and engineering, dissipation is often used to filter incoherent waves, producing a pure coherent output. Here, we apply this principle to topological states, creating a linear filter that effectively isolates a specific topological state regardless of the initial input's coherence properties. This approach creates a dissipation-free topological subspace, where the desired states are preserved and their topological protection is enhanced. Our work provides a versatile and simple method for topological state selection, opening the door to new applications in integrated topological photonics.
