Fig. 6

Dispersion curves, cross-sectional shapes, and transmission spectra of NPM structures corresponding to different geometric parameters: (a) \(\:\alpha\:=10^\circ\:\); (b) \(\:\:\alpha\:=20^\circ\:\); (c) \(\:\alpha\:=30^\circ\:\); (d) \(\:\alpha\:=40^\circ\:\).