Fig. 3

The dependences of the SPR position, θ _min, on the refractive index of the environment, n, for Au standard sensors with a flat surface (curve 1 in a–c) and Au gratings with period of 296.6 ± 0.5 nm and depth of relief of 13.5 ± 2 nm (curve 2 in a) and 21.0 ± 2 nm (curve 2 in b). Curve 2 in c gives the dependence of θ _min on n for the Au grating with period of 302.0 ± 0.5 nm and average depth of relief of 17.5 ± 2 nm