Figure 3: SPP radiation patterns of a hole-antenna system containing 5 holes, having a linear phase slope.

(a–c) Zero phase slope, (d–f) consecutive holes have a phase difference of 0.22π and (g–i) consecutive holes have a phase difference of π. (a,d,g) Show the real part of L_y. (b,e,h) Show the absolute value of the 2D Fourier transform of L_y. (c,f,i) Are polar plots of the SPP intensity on a logarithmic scale. The experimental data is plotted in green while the black lines represent the modeled radiation patterns of the SPPs. The hole spacing is 950 nm as can be seen in the SEM micrograph in Fig. 1.