Regensburg 2019 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 14: Poster

DS 14.37: Poster

Dienstag, 2. April 2019, 17:00–20:00, Poster E

Understanding the Limits of Plasmonic Sensitivity and Tip-Enhanced Raman Spectroscopy — •Lu He, Mafuhjur Rahaman, Teresa Isabel Picoto Pena Madeira, and Dietrich R.T. Zahn — Reichenhainerstraße 70 P181 Chemnitz Germany

Tip-Enhanced Raman Spectroscopy has attracted growing interest over the last decades. Due to the confined electric field at the metallic tip apex, one can both enhance the Raman sensitivity, and reduce the probing area significantly. The enhancement factor can be large enough to enable this technique to be sensitive to detailed structures[1] and orientation of surface species[2] well beyond the diffraction limit of light reaching a spatial resolution of about 2 nm[1,2]. For a metal-metallic tip-sample system, the full width at half maximum (FWHM) of the local electric field is estimated by 2*sqrt(Rd), with R is the radius of the tip and d is the tip-sample distance[3]. However, the situation can be different if the substrate structure is smaller than the tip radius R. In this contribution we will address this issue by calculating the local electric field using finite element method simulations and varying the substrate dimensions. Our simulations will not only provide a deeper understanding of the TERS mechanism of such structures, but also help in realizing highly efficient TERS experiments using similar systems.