Towards probing THz-driven transient electronic states with time-resolved ARPES


Towards probing THz-driven transient electronic states with time-resolved ARPES

Deinert, J.-C.; Green, B. W.; Kovalev, S.; Gensch, M.

In this contribution, we present the concept for a novel experimental setup at the THz facility TELBE at Helmholtz-Zentrum Dresden-Rossendorf [1], which combines THz excitation with intrinsically surface-sensitive time- and angle-resolved photoelectron spectroscopy (tr-ARPES). THz excitation provides resonant access to a multitude of fundamental modes, e.g., lattice vibrations, molecular rotations, spin precession and the motion of free electrons. Thereby it can be a handle to control highly relevant transient material properties, from metal-insulator-transitions [2] to superconductivity [3] and catalytic activity [4]. The obvious way of probing these THz-driven dynamics is tr-ARPES which enables direct access to the surface electronic states on a femtosecond timescale, thereby complementing current purely optical techniques. However, the implementation of THz pump – tr-ARPES probe experiments (cf. Fig. 1) has been impeded, because of the unmet requirement for high duty cycle THz sources (>> 10 kHz repetition rate quasi-cw) to provide sufficient statistics for tr-ARPES.
This limitation is overcome at TELBE which offers tunable and CEP-stable THz pulses at a repetition rate of 100 kHz based on superradiant emission, and timing stability of < 30 fs due to a novel pulse-to-pulse diagnostics scheme [5]. Over the next three years, a tr-ARPES setup shall hence be implemented at the THz facility TELBE which aims at establishing feasibility and dynamic range despite obvious obstacles such as residual streaking of the photoelectrons by the high THz excitation fields.
This contribution discusses the challenges and the opportunities of tr-ARPES in first THz control experiments and will outline the current design of the planned tr-ARPES endstation.

[1] B. Green et al., Sci. Rep. 6, 22256 (2016).
[2]T. Kampfrath et al., Nature Photonics 7, 680-690 (2013)
[3]D. Nicoletti and A. Cavalleri, Adv. Opt. Photon. 8, 401 (2016).
[4]L. A. Pellouchoud and E. J. Reed, Phys. Rev. A 91, 052706 (2015).
[5]S. Kovalev et al., Struct. Dyn. (2017) (under review).

Related publications

  • Poster
    Ultrafast Surface Dynamics 10, 11.-16.06.2017, Inzell, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-25683
Publ.-Id: 25683