Uniform Loss Enables Unidirectional Edge Transport in Photonic Crystals via Non-Hermitian Skin Effects
Researchers have demonstrated theoretically and experimentally that uniform loss in photonic crystals can convert bidirectional edge states into unidirectional-like wave transport through non-Hermitian skin effects. The work uses a core-cladding geometry where domains share identical Chern numbers but differ in bulk polarization, allowing loss alone to reshape the spectral topology of edge bands. The finding offers a structurally simple, universal route to one-way wave propagation without requiring engineered nonreciprocity or spatially patterned loss.
A study posted to arXiv on June 9, 2026 reports that uniform loss — previously overlooked as a control mechanism — can activate non-Hermitian skin effects (NHSEs) in photonic crystals that break time-reversal symmetry. By designing a core-cladding geometry in which adjacent domains share identical Chern numbers but have distinct bulk polarizations, the authors show that adding uniform loss induces point gap windings in the spectral topology of edge bands, enforcing one-way propagation. Near-field measurements confirmed that what were intrinsically bidirectional interface states became unidirectional-like circulation around the entire domain wall, with experimental results in excellent agreement with theoretical predictions. Prior experimental realizations of NHSEs typically required either engineered nonreciprocity or spatially patterned loss, making this uniform-loss approach considerably simpler to implement. The authors argue their results establish a general principle applicable beyond the specific photonic crystal platform demonstrated.
What's missing
The study is a preprint and has not yet undergone peer review. The authors do not discuss the scalability of the approach to other frequency regimes (e.g., microwave or acoustic systems) or the practical insertion losses that uniform dissipation would impose in device applications. Long-term stability and fabrication tolerances of the core-cladding geometry are not addressed.
What different sources said
- arXiv physicsCenter
Unidirectional-like Edge Transport Induced by Non-Hermitian Skin Effects
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