Characterisation of metallic particle distributions by scanning near-field optical microscopy (SNOM) in simultaneous reflection and transmission mode

Unlike conventional optics, scanning near-field optical microscopy (SNOM) overcomesthe Rayleigh criterion and can therefore achieve better resolutions than conventionaloptical microscopes. This feature is utilized to measure the optical propertiesof different silver particle distributions on a glass surface. This paper mainlylays focus on intensity correction of the optical data due to topographical artifacts,analysis of plasmonic behavior and a tentative representation of the optical data.The simple approach for optical artifact correction has been shown to yield qualitativesuccess, with necessity of improvement for quantitative results. Given theconditions of the experiment, it has also been observed that plasmonic couplingseems to have a greater impact on the small observed particles. The tentative representationof the optics suggests that the larger particles are able to emit light byabsorption of electromagnetic energy from their surrounding.