title: Quantitative imaging of the optical near field.
abstract: When exposing small particles on a substrate to a light plane wave, the scattered optical near field is spatially modulated and highly complex. We show, for the particular case of dielectric microspheres, that it is possible to image these optical near-field distributions in a quantitative way. By placing a single microsphere on a thin film of the photosensitive phase change material Ge(2)Sb(5)Te(5) and exposing it to a single short laser pulse, the spatial intensity modulation of the near field is imprinted into the film as a pattern of different material phases. The resulting patterns are investigated by using optical as well as high-resolution scanning electron microscopy. Quantitative information on the local optical near field at each location is obtained by calibrating the material response to pulsed laser irradiation. We discuss the influence of polarization and angle of incidence of the laser beam as well as particle size on the field distribution. The experimental results are in good quantitative agreement with a model based on a rigorous solution of Maxwell's equations. Our results have potential application to near-field optical lithography and experimental determination of near fields in complex nanostructures.
authors.affiliation: Faculty of Physics, Universität Konstanz, Universittsstraße 10, 78457 Konstanz, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Kühler
authors.forename: F Javier
authors.initials: FJ
authors.lastname: García de Abajo
authors.forename: Philipp
authors.initials: P
authors.lastname: Leiprecht
authors.forename: Andreas
authors.initials: A
authors.lastname: Kolloch
authors.forename: Javier
authors.initials: J
authors.lastname: Solis
authors.forename: Paul
authors.initials: P
authors.lastname: Leiderer
authors.forename: Jan
authors.initials: J
authors.lastname: Siegel
mesh_terms: D003198:Computer Simulation; D008027:Light; D008962:Models, Theoretical; D057054:Molecular Imaging / Q000379:methods*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D012542:Scattering, Radiation