Unidirectional reflectionlessness of a non-PT-symmetric large-sized nonperiodic multilayer structure consisting of lossy amorphous silicon and lossless silica layers.
(A) SEM pictures of the cross-section of the fabricated EP structure. The scale bar corresponds to 50 nm. (B and C) Numerically calculated and experimentally measured reflection spectra of the EP structure from 450 to 600 nm, respectively, for both forward (red) and backward (black) incidence. (D and E) Photographs of the wafer-scale EP structure in forward and backward directions, respectively, with a 10-nm band-pass filter centered at the wavelength of 520 nm .