Within the work group Nanoscopy topics regarding fundamental aspects of plasmon-based near field spectroscopy and plasmon-based substrate-probe interaction in general are investigated. Independent experiments and also theoretical models for both departments are pursued.
Resolution of TERS probes
Physical models are developed to describe and determine the realistic nanoscale roughness of so-called TERS (tip-enhanced Raman Spectroscopy)-probes,consequently providing a physical base for the actual experiments. Thus, experiment and theory drive each other keeping a close proximity to potential applications.
Experiments show that the energy needed for chemical reaction, e.g. for plasmon-based azo-coupling, is considerably below that of a neat photo-reaction. Based on quantum-mechanic models the interaction of plasmonic probes and the actual sample is studied. The results give clear evidence for the involvement of so-called hot electrons and are the target of further analysis such as plasmon-stimulated structuring of substrate surfaces.
Special experimental conditions have to be provided to meet the requirement of the high spatial resolution. Ultra-flat gold and silver substrates, respectively, are of high importance and are developed in cooperation with the research department Nanooptics. To the same degree optimisation of plasmonic near-field probes is an important aspect of the group. A medium term aim is the establishment of a pulsed laser system for the investigation of dynamic processes on the nanometre scale in cooperation with the research department Functional Interfaces.