Figure 4

Structural tunability of the broadband ZBS.
Contour plots of the BS efficiency as a function of the incident wavelength and the core radius for different shell thicknesses. From the bottom panel to the top panel, the shell thickness increases from t = 160 nm to t = 220 nm. The solid horizontal arrow and dashed vertical line in each panel indicates the broadband ZBS in the horizontal (wavelength) and vertical (core radius) dimensions, respectively.