Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 4: Plasmonics and Nanooptics I: Light-Matter Interactions
O 4.3: Talk
Monday, March 20, 2017, 11:00–11:15, TRE Ma
Pump-probe nanoscopy with NIR to deep THz radiation — •F. Kuschewski1, S.C. Kehr1, J. Döring1, N. Awari2, B. Green2, S. Kovalev2, M. Gensch2, and L.M. Eng1 — 1Institut für Angewandte Physik, TU Dresden — 2Helmholtz-Zentrum Dresden-Rossendorf
Recently, scattering-type scanning near-field infrared microscopy (s-SNIM) was successfully combined with pump-probe experiments pushing the temporal resolution of s-SNIM down to a few fs [1]. That combination offers spectacular possibilities to explore the dynamics of nanoscale physical devices, but usually shows a low optical contrast due to high background signals. We analyzed the frequency spectrum in pump-probe s-SNIM finding sidebands to the main carrier frequency that provide a much higher signal-to-noise ratio, as proven both by simulations and recent experiments [2]. Experimentally a greatly increased contrast in the 1st order sideband was found [2], that now has been extended up to the 5th order, applying s-SNIM to a structured gold/semiconductor sample. Note that our approach is applicable to the broad spectral range from visible to THz wavelengths.
[1] M. Wagner et al. Nano Lett. 14, 894 (2014).
[2] F. Kuschewski et al. Sci. Rep. 5, 12582 (2015).