Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 2: Scanning probe techniques: Method development I

O 2.4: Vortrag

Montag, 12. März 2018, 11:15–11:30, MA 004

Setup of a THz-STM for pump-probe experiments using a commercial THz-source — •Philip Kapitza, Hüseyin Azazoglu, Christian Bobisch, and Rolf Möller — Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstr. 1, 47057 Duisburg, Germany

To study the excitations of single atoms or molecules on their intrinsic timescales ultrafast temporal and atomic-scale spatial resolution is essential. This can be achieved by combining the very high spatial resolution of a scanning tunneling microscope (STM) with picosecond duration terahertz (THz) pulses. When coupled to the tip of a STM the THz pulses can modulate the bias voltage in the tunneling junction [1,2,3].

The setup presented in this talk consists of a homebuilt low-temperature STM (LT-STM) and a commercial THz-pulse source for time domain spectroscopy (THz-TDS). The THz-emitter of this THz-TDS system is a photoconducting antenna irradiated by a fs-IR laser.

A laser diode is used for the adjustment and focus of the terahertz beam onto the STM tip. First measurements of the time-dependent tunnel current response as well as possible setup for pump-probe-experiments using two terahertz emitters will be presented.

[1] Cocker, T. L. et al., Nat. Photon. 7, 620-625 (2013).

[2] Cocker, T. L. et al., Nature 539, 263-267 (2016).

[3] Yoshioka, K. et al., Nat. Photon. 10, 762-765 (2016)