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 Karl Franzens University Graz

Graz University of Technology 

From STED Microscopy to STED Lithography
Prof. Dr. Thomas A. Klar
Institut für Angewandte Physik, Johannes Kepler Universität Linz, Österreich
17:15 - 18:15 Tuesday 17 November 2015 TUG P2

In 1873, Ernst Abbe has found that resolution in microscopy should be limited to a third of the wavelength.[1] This so called diffraction limit kept its dogmatic character for about 130 years, which is surprising because modern quantum chemistry and quantum optics, which were fully developed at the end of the twenties of the last century, provide basically all necessary ingredients to break this limit. Nevertheless, this fact was ignored for about 65 years until Stefan Hell dared to tackle this dogma and to postulate that taking quantum physics and –optics serious could possibly break the Abbe diffraction limit.[2]

This talk will briefly sketch the experimental realisation of a STED microscope [3] and related techniques. On top of imaging, STED can also be used to improve the resolution and decrease the structure size in lithography, which was postulated in the early days of STED [3] but realized only recently [4, 5]. This enables writing three dimensional structures comprising sizes of some tens of nanometers only. The structures show good biocompatibility and allow for bio-functionalization with proteins, down to the single protein level [6, 7].

[1] Abbe E.: Beiträge zur Theorie des Mikroskops und der mikroskopischen Wahrnehmung. Archiv für Mikroskopische Anatomie 1873; 9: 413-68.
[2] Hell S. W., Wichmann J.: Breaking the diffraction resolution limit by stimulated emission: stimulated-emission-depletion fluorescence microscopy. Optics Letters 1994; 19(11): 780-2.
[3] Klar T. A., Hell S. W.: Subdiffraction resolution in far-field fluorescence microscopy. Optics Letters 1999; 24(14): 954-6.
[4] Fischer J., Wegener M.: Three-dimensional direct laser writing inspired by stimulated-emission-depletion microscopy. Optical Materials Express 2011; 1(4): 614-24.
[5] Wollhofen R., Katzmann J., Hrelescu C., Jacak J., Klar T. A.: 120 nm resolution and 55 nm structure size in STED-lithography. Optics Express 2013; 21(9): 10831-40.
[6] Wiesbauer M., Wollhofen R., Vasic B., Schilcher K., Jacak J., Klar T. A.: Nano-Anchors with Single Protein Capacity Produced with STED Lithography. Nano Letters 2013; 13(11): 5672-8.
[7] Wolfesberger C., Wollhofen R., Buchegger B., Jacak J., Klar T. A.: Streptavidin functionalized polymer nanodots fabricated by visible light lithography. Journal of Nanobiotechnology 2015; 13: 27.