Berlin 2008 – scientific programme
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O: Fachverband Oberflächenphysik
O 88: Metallic Nanostructures II (on Semiconductors)
O 88.8: Talk
Friday, February 29, 2008, 11:15–11:30, MA 005
Two metal nano-particle enhanced Raman spectroscopy and microscopy — •Phillip Olk1, Jan Renger2, Marc Tobias Wenzel1, Thomas Härtling1, and Lukas M. Eng1 — 1Institut für angewandte Photophysik, TU Dresden — 2ICFO-Institut de Ciencies Fotoniques, Barcelona
The distance and polarization dependent near-field enhancement of two coupling metal nanoparticles (MNPs) is analyzed by means of the novel Scanning Particle-enhanced Raman Spectroscopy (SPRM) technique [1]. In contrast to single MNP Raman experiments, the near-field coupling between two dissimilar MNPs leads to a Raman hot spot yielding an extra enhancement factor, as proven here both in experiment and theory.
The Au80 MNP is attached to the apex of an optical fiber manipulator and exposed to the exctitation light. A monolayer of 1-octanethiol molecules covering the Au80 MNP serves as the electric field prober when scanning the substrate carrying the Au30 MNP through the optical focus.
This constellation allows recording the Raman signatures from a very low number of well confined molecules. Moreover, also the spectral and spatial dependence could be explored with a superb sensitivity and very low integration time.
[1] P. Olk, J. Renger, T. Härtling, M. T. Wenzel, and L. M. Eng. Nano Lett. 6(7), 1736–1740, 2007.