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arXiv · 1811.00715

A setup for extreme-ultraviolet ultrafast angle-resolved photoelectron spectroscopy at 50-kHz repetition rate

Jan Heye Buss·He Wang·Yiming Xu·Julian Maklar·Frederic Joucken·Lingkun Zeng·Sebastian Stoll·Chris Jozwiak·John Pepper·Yi-De Chuang·Jonathan D. Denlinger·Zahid Hussain·Alessandra Lanzara·Robert A. Kaindl
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Abstract

Time- and angle-resolved photoelectron spectroscopy (trARPES) is a powerful method to track the ultrafast dynamics of quasiparticles and electronic bands in energy and momentum space. We present a setup for trARPES with 22.3 eV extreme-ultraviolet (XUV) femtosecond pulses at 50-kHz repetition rate, which enables fast data acquisition and access to dynamics across momentum space with high sensitivity. The design and operation of the XUV beamline, pump-probe setup, and UHV endstation are described in detail. By characterizing the effect of space-charge broadening, we determine an ultimate source-limited energy resolution of 60 meV, with typically 80-100 meV obtained at 1-2e10 photons/s probe flux on the sample. The instrument capabilities are demonstrated via both equilibrium and time-resolved ARPES studies of transition-metal dichalcogenides. The 50-kHz repetition rate enables sensitive measurements of quasiparticles at low excitation fluences in semiconducting MoSe$_2$, with an instrumental time resolution of 65 fs. Moreover, photo-induced phase transitions can be driven with the available pump fluence, as shown by charge density wave melting in 1T-TiSe$_2$. The high repetition-rate setup thus provides a versatile platform for sensitive XUV trARPES, from quenching of electronic phases down to the perturbative limit.

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Jan Heye Buss, He Wang, Yiming Xu, Julian Maklar, Frederic Joucken, Lingkun Zeng, Sebastian Stoll, Chris Jozwiak, John Pepper, Yi-De Chuang, Jonathan D. Denlinger, Zahid Hussain, Alessandra Lanzara, Robert A. Kaindl. 2019-02-21. A setup for extreme-ultraviolet ultrafast angle-resolved photoelectron spectroscopy at 50-kHz repetition rate. https://doi.org/10.1063/1.5079677

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