Magneto-optical photonic crystal slab

Magnetic field tunes exceptional points

Introducing an external magnetic field as an extra topological parameter enables continuous tuning and topological restructuring of non-Hermitian exceptional points in a photonic crystal slab.

Xingqi, Zhao · Wang, Jiajun · Liu, Wenzhe · Shi, Lei · Zi, Jian

Physical Review Letters 2025

Advantages

Closed exceptional point ring continuously evolved by external magnetic field

Paired exceptional points approach and annihilate as Fermi arc shrinks

Closed ring topology in Poincaré sphere

Topological charge transfers between Fermi arc and circularly polarized states