Fig. 3
From: Antenna surface plasmon emission by inelastic tunneling
Plasmon emission. a Image of the source plane showing the electrical excitation of SPP (under a biased voltage of 1.6 V). The white rectangle indicates the area of the array of antennas (the scale bar is 25 μm). b Cross-section profile along the x-axis in a semi-log plot is averaged over the y-axis in the yellow dashed line rectangle (red dots are experiment data, the blue smoothed curve is a guide to the eye to see the SPP profile, the propagation length of the SPP is 4.9 ± 0. 3 μm. c Experimental back focal plane image, showing the plasmon emission between k/k0 = 1.0 (light cone in air) and k/k0 = 1.3 (immersion objective numerical aperture), where k0 = ω/c and k2 = kx2 + ky2, kx = n k0 sinθ cosϕ, where n = 1.5 is the refractive index of the substrate. d Simulated back focal plane image (at wavelength of 850 nm and the width of patch is 132 nm)
