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

Bachelor Thesis from the year 2014 in the subject Physics - Optics, grade: 1,3, Free University of Berlin, language: English, abstract: Unlike conventional optics, scanning near-field optical microscopy (SNOM) overcomes the Rayleigh criterion and can therefore achieve better resolutions than conventional optical microscopes. This feature is utilized to measure the optical properties of different silver particle distributions on a glass surface. This paper mainly lays 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 qualitative success, with necessity of improvement for quantitative results. Given the conditions of the experiment, it has also been observed that plasmonic coupling seems to have a greater impact on the small observed particles. The tentative representation of the optics suggests that the larger particles are able to emit light by absorption of electromagnetic energy from their surrounding.