Figure 19.

(a) 16 dielectric cuboids (purple) placed on the silver substrate (blue); (b) enhancement G as function of wavenumber for the dielectric cuboids placed on silver substrate, unit-cell dimensions of $D_x=650$nm, $D_y=550$nm, dielectric cuboid dimensions of $dx$ = 585 nm, $dy$ = 495 nm, and height $h=55$nm. The incident laser beam is normal to metasurface, electric field in the beam is directed along the diagonal of the dielectric blocks. The enhancement G is obtained at the surface of dielectric cuboid; (c) local electric field mapping on the top of dielectric cuboids of the first resonance shown in (b) (from [17]).