Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 19: Poster Monday: Scanning Probe Techniques 1

O 19.7: Poster

Montag, 5. September 2022, 18:00–20:00, P4

Implementation of a SPPX Setup and investigation of the delay-time modulation induced intensity modulation — •Marlo Teichmann, Georg Traeger, and Martin Wenderoth — V. Physical Institute, University of Göttingen, 37077, Göttingen, Germany

Shaken-pulse-pair-excited STM (SPPX-STM) successfully combines optical pump-probe techniques with STM to obtain high temporal and spatial resolution [1]. SPPX-STM achieves this by introducing a modulation of the delay time between pump- and probe pulses. The modulation of the delay time instead of the intensity leads to a constant thermal load and hence minimizes thermal effects. However, recent studies have shown that higher harmonics of this modulation causes additional undesirable signals in time resolved measurements [2].

In this study, we implemented a SPPX setup with two semiconductor lasers. These lasers can be triggered electronically which allows for delay times below 1ns between pump- and probe pulse. We implemented two different pump probe schemes to suppress the additional signals, caused by the SPPX-Method. By choosing an improved modulation scheme, we show that it is possible to suppress the contribution of the higher harmonic signals by more than one order of magnitude.

[1] Kloth et al. Rev. Sci. Instrum. 87 (2016)

[2] Takeuchi et al. 2019 Jpn. J. Appl. Phys. 58 SIIA12