Fig. 2

a Simulated NFE map for the grating with ff = 0.47 under 488 nm TM-polarized excitation. D₁ and D₂ present the detection lines over which the NFIE values were calculated. The geometrical parameters are h₁ = 1 μm, h₂ = 225 nm, h₃ = 275 nm and d = 300 nm; b Maximum and c average values of NFIE at 450 nm, 600 nm and 800 nm calculated for the same grating with ff = 0.47. In b and c, the blue (square) and red (triangle) discrete data points show the NFIE values at the corresponding wavelengths calculated over D₁ and D₂, respectively, while the blue and red vertical axes correspond to the blue and red data points