Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 15: Methods: Scanning Probe Techniques II
O 15.13: Vortrag
Montag, 26. März 2007, 17:15–17:30, H41
A 30-nm-wide slit as a waveguide for light to the aperture of a near-field optical probe — •Daniela Diessel1, Nicole Neuberth1, Fabián Pérez-Willard2, and Andreas Naber1 — 1Institut für Angewandte Physik, Universität Karlsruhe (TH) — 2CFN Service Laboratory, Universität Karlsruhe (TH)
Recently we have introduced a triangular aperture probe (TA probe) for scanning near-field optical microscopy (SNOM) that combines a high optical resolution capability with a high transmission of light [1]. The near-field pattern is highly confined to only one side of the triangular aperture so that the resolving power is almost doubled as compared to a circular aperture of equal size. We could demonstrate that the TA probe is particularly suited for imaging of single molecules at a resolution down to 30 nm [2]. So far, we created the aperture by controlled squeezing of the entirely aluminum-coated tip against a smooth surface. Now we applied focused ion beam (FIB) milling for aperture formation which allowed us to routinely fabricate triangular apertures with a side length even below 20 nm. To further increase the transmission of the TA probes we used a FIB to produce a 30-nm-wide slit into the metal surface as a waveguide for light to the aperture. As a result of the slit-waveguide we observed a considerable enhancement of the near-field optical intensity at the aperture.
[1] G. Colas des Francs et al., Phys Rev B 72, 165111 (2005).
[2] D. Molenda et al., Optics Expr. 13, 10688 (2005).