Topological and non-Hermitian photonics controlled by hybrid photonic crystals

We propose and demonstrate novel hybrid photonic crystals, which consist of host photonic crystals loaded by patterned functional materials. A key point is that host and loaded layers have different symmetry, which enables effective control of symmetry-related properties in topological photonics and non-Hermitian photonics. We show two examples: phase-change material, GST-loaded photonic crystal for topological phase transition induced by the material phase transition, and graphene-loaded photonic crystals for manipulating exceptional points and non-Hermitian chiral properties.