A narrow bandwidth extreme ultra-violet light source for time- and angle-resolved photoemission spectroscopy

Qinda Guo; Maciej Dendzik; Antonija Grubišić-Čabo; Magnus H Berntsen; Cong Li; Wanyu Chen; Bharti Matta; Ulrich Starke; Björn Hessmo; Jonas Weissenrieder; Oscar Tjernberg

doi:10.1063/4.0000149

A narrow bandwidth extreme ultra-violet light source for time- and angle-resolved photoemission spectroscopy

Struct Dyn. 2022 Apr 28;9(2):024304. doi: 10.1063/4.0000149. eCollection 2022 Mar.

Affiliations

¹ Department of Applied Physics, KTH Royal Institute of Technology, Hannes Alfvéns väg 12, 114 19 Stockholm, Sweden.
² Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany.

Abstract

Here, we present a high repetition rate, narrow bandwidth, extreme ultraviolet photon source for time- and angle-resolved photoemission spectroscopy. The narrow bandwidth pulses $Δ E = 9, 14, and 18$ meV for photon energies $h ν = 10.8, 18.1, and 25.3$ eV are generated through high harmonic generation using ultra-violet drive pulses with relatively long pulse lengths (461 fs). The high harmonic generation setup employs an annular drive beam in tight focusing geometry at a repetition rate of 250 kHz. Photon energy selection is provided by a series of selectable multilayer bandpass mirrors and thin film filters, thus avoiding any time broadening introduced by single grating monochromators. A two stage optical-parametric amplifier provides < 100 fs tunable pump pulses from 0.65 μm to 9 μm. The narrow bandwidth performance of the light source is demonstrated through angle-resolved photoemission measurements on a series of quantum materials, including high-temperature superconductor Bi-2212, WSe₂, and graphene.