Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 32: Plasmonics and Nanophotonics II (Joint Session O/DS/HL)
O 32.1: Vortrag
Dienstag, 23. März 2010, 15:00–15:15, H2
Nanolocalization of time-reversed optical fields propagating in random scattering media — •Dominik Differt1, F. Javier Garćia de Abajo2, and Walter Pfeiffer1 — 1Fakultät für Physik, Universität Bielefeld, Universitätstr. 25, 33516 Bielefeld, Germany — 2Instituto de Optica, CSIC, Serrano 121, 28006 Madrid, Spain
The far field emission pattern of a nanoscale light emitter positioned in a nanoscale random scattering environment contains information about the localized emission. Because of the reciprocity of electromagnetic wave propagation time-reversing the outgoing wave creates an excitation that propagates back to the emitter and localizes on a sub-diffraction length scale. The electromagnetic response of a random scattering environment is calculated based on a multiple scattering approach. The here investigated scattering environment is characterized by a geometrical hierarchy. On a subwavelength scale the emitter is surrounded by metal nanoparticles acting as a random antenna coupling radiation to the far field. On the scale of tens of microns, several wavelengths distance to the emitter, this structure is embedded in randomly distributed dielectric scatterers acting a permeable reverberation shell. The degree of nanolocalization of a time-reversed planar wave component of the outgoing scattered wave depends on this geometrical hierarchy and the density of scatterers, i.e. the wave mixing occurring in the reverberation shell.