Regensburg 2002 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 6: Poster: Neue Methoden

CPP 6.11: Poster

Montag, 11. März 2002, 13:30–15:00, B

Near-field optical microscopy — •Peter Reineker und Elisabeth Paule — Abteilung Theoretische Physik, Universität Ulm, 89069 Ulm, Germany

Optical microscopy plays an important role in the investigation of condensed matter and of biological systems. A considerable disadvantage of conventional optical microscopy is the limited resolution of about half an optical wavelength. To overcome this limit, in 1928 Synge suggested to use the optical near field of a tip and not the far field. The resolution of the microscpe in this case is determined by the diameter of the tip. Decreasing the diameter increases the resolution, but simultaneously decreases the intensity of the evanescent light wave. In 1990 Lieberman et al. suggested to use a socalled supertip in which not electromagnetic but excitonic energy transfer is decisive. In this contribution we theoretically investigate the properties of such a microscope. To that end we describe the substrate, the sample and the tip by a microscopic model taking into account excitation energies and transfer integrals between all molecular units as well as the coupling to the light field. The coupled system of Schrödinger and Maxwell’s equations is solve numerically. Using this solution we discuss the resolution and the contrast and the resolution of the microscope.