Regensburg 2007 – scientific programme
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O: Fachverband Oberflächenphysik
O 13: Symposium: Ultrafast Nanooptics II
O 13.1: Invited Talk
Monday, March 26, 2007, 14:15–14:45, H38
Nanoscale optical spectroscopy based on local field enhancement — •Achim Hartschuh1, Huihong Qian1, Tobias Gokus1, Neil Anderson2, and Lukas Novotny2 — 1Department Chemie und Biochemie and CeNS, LMU Muenchen, Germany — 2The Institute of Optics, University of Rochester, USA
Spectroscopic techniques with nanoscale spatial resolution are essential for the detection and analysis of individual nanoobjects and nanostructured materials. We study and apply a near-field optical technique that is based on local field enhancement at the apex of a laser-illuminated metal tip. In this scheme, locally enhanced excitation and radiation fields in close proximity to the near-field probe are used to amplify the optical response of the sample. At present, using monochromatic cw-excitation, we achieve a spatial resolution of about 10 nm for both photoluminescence and Raman scattering of carbon nanotubes [1, 2]. Different contributions to the signal enhancement of photoluminescence and Raman scattering are evaluated based on experimental data achieved simultaneously for the same nanotube. The high-resolution capability of the technique is accompanied by an enhanced detection sensitivity making it ideally suited for nanoscale surface and sub-surface imaging [3]. We discuss strategies for the advancement of the technique and its combination with ultrafast laser spectroscopy.
[1] A. Hartschuh et. al, Phys. Rev. Lett. 90, 095503 (2003). [2] A. Hartschuh et. al, Nano Lett. 5, 2310 (2005). [3] N. Anderson, Nano Lett. 6, 744 (2006).