Imaging of surface plasmon polariton propagation on a Au thin film by using tip-enhanced Rayleigh scattering

Surface plasmon polariton (SPP) propagation on a Au thin film has been observed by tip-enhanced Rayleigh scattering. The interference pattern has been observed around the edge of the film. The interference is due to the near-field scattering light at the tip and SPP radiation from the edge of the film. From the interference width, we evaluated the wave number of SPP on the Au film. By changing the wavelength of the incidence light, we have obtained the dispersion relation of the SPP. The experimentally obtained dispersion relation is well corresponding to the calculated one using bulk Au parameters.