Credit: eLight
(a) Scanning electron microscope (SEM) image of a channel waveguide (WG) with a lithographically defined symmetric meta-unit on SOI substrate. (b) Scanning electron microscope (SEM) image of a channel waveguide (WG) with a lithographically defined rectangular-shaped symmetric Mie-scatterer on SOI substrate (top). Design parameter space for such Mie scatterer (bottom). (c) Optical impedance matching of the complex reflection coefficient to obtain zero reflection at exceptional point (EP).