Edge plasmon mediated tip enhanced spectroscopy

• Applicant: Dr. Ulrich Fischer
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2010 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 167438810

Tip enhanced spectroscopy (TES) combines the concepts of surface enhanced spectroscopy and near field optical microscopy. TES is often realised with a metal tip and an external illumination. We used a metal coated tetrahedral tip (T-tip) with an intemal illumination. We showed by numerical calculations, that a plasmon edge mode of the edges of the T-tip can serve as an efficient channel for the super focusing of an incident beam of light to a highly localized tip excitation as well as a detection channel for the emission of a dipole at the tip apex into a highly directional beam of light into the tip. A TES configuration will be realized which takes full advantage of these excitation and detection channels in order to increase the sensitivity of TES. Different applications of TES will be explored. As there is an urgent need for the analysis of the molecular composition of surfaces with a resolution below 100 nm, imaging of surfaces by TERS (Tip Enhanced Raman Scattering) will be expolored to analyze the molecular composition of surfaces. In addition, T-tips which are coated with Raman active molecules serve as a Near Field Raman Probe where the TERS signal of the probe is used as a tool for imaging of surface properties by their selective influence on the probe's TERS spectmm. Tip enhanced fluorescence spectroscopy will be applied to imaging of photosynthetic membrane, preparations.

• DFG Programme: Research Grants
• Participating Person: Professor Dr. Harald Fuchs