Fig. 4

Calculated spatial field distributions of electric (a–d) and magnetic (e–h) fields for normal light incidence. The wavelength of incident light is 372 nm (a, e), 546 nm (b, f), 635 nm (c, g), and 1113 nm (d, h). The black dash lines denote the cross section of the structure. Here, the parameters of the structure are set as p = 200 nm, w = 60 nm, h₁ = 20 nm, h₂ = 250 nm, h₃ = 200 nm, and ε₂ = 3.1