Fig. 1: Correspondence between bulk band topology and far-field radiation.
From: Observation of Berry curvature in non-Hermitian system from far-field radiation
A The schematic of radiation process from the PhC slab to the far field in real space. The wavefunction of the Bloch mode \(| {u}_{n}\left.\right\rangle\) in the PhC slab is diffracted by the periodic lattice into several diffraction directions, acting as the radiation channels C1−3. Each channel (i.e. C3) depends on a 3D wavevector (i.e., k3), and can be described by the polarization vector (i.e., \(| {\Psi }_{n,3}\left.\right\rangle\)) marked as the spiral arrows. The 3D wavevector for each channel (i.e., k1 for channel C1) can be decomposed to the vertical component (i.e., kz,1) and in-plane component (i.e., β1), both determined by the Bloch wavevector k∥. B The “bulk-radiation correspondence" of Berry curvature in momentum space. The radiation polarization field (middle panel) can bridge the bulk Berry curvature Bn defined in wavefunction \(| {u}_{n}\left.\right\rangle\) (bottom panel) with the radiation Berry curvature \({B}_{n}^{r}\) defined in far-field radiation vector \(| {\Psi }_{n}\left.\right\rangle\) (top panel). cx,y are complex amplitudes of the radiative waves in the x−y plane.
