Chiral Exceptional Lines in the Visible

Strong circular polarization response

First experimental observation of chiral exceptional lines in the visible regime, enabling polarization-selective devices and chiral light control.

Xinhao, Wang · Liu, Wenzhe · Yuyang, Xu · Wang, Jiajun · Shi, Lei · Chan, C. T. · Zi, Jian

Physical Review Letters 2026

Advantages

No complex structures

The scattering matrix of a simple two-dimensional photonic crystal provides the required parameter space through frequency and in-plane momenta, avoiding complex structural engineering.

Strong chiral response

The exceptional lines exhibit distinct responses to left- and right-handed circular polarizations, enabling polarization-selective devices and chiral light control.

Topologically robust

The exceptional lines extend continuously across the frequency-momentum space, demonstrating topological robustness.

Applications

• Polarization-selective devices：Exploit distinct responses to circular polarizations for devices that selectively transmit left or right circularly polarized light.
• Chiral light control：Control the propagation and polarization state of chiral light in the visible regime.
• Non-Hermitian photonics：Provide a robust platform for investigating non-Hermitian topological physics at visible frequencies.