Fig. 6

Influences of the symmetry of the structure on transmission responses of the PNS. Other parameters are the same as Fig. 1c with Δ =  − 28 nm. The insert figures indicate the schematic diagram of the superlattice of the PNS. a Transmission 2D map of the PNS as a function of the radius r′ of two nanoholes, where the structural symmetry of the superlattice along the x axis is maintained. b Transmission 2D map of the PNS as a function of the radius r′ of two nanoholes, where the structural symmetry of the superlattice along the x axis is broken