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

Here, we present a high repetition rate, narrow bandwidth, extreme ultraviolet photon source for time- and angle-resolved photoemission spectroscopy. The narrow bandwidth pulses & UDelta; E = 9 , 14 , and 18 meV for photon energies h nu = 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 mu m to 9 mu m. 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. (C) 2022 Author(s).

Automated summary

A high repetition rate, narrow bandwidth extreme ultraviolet photon source is presented for time- and angle-resolved photoemission spectroscopy. The source produces narrow bandwidth pulses with photon energies of 10.8 eV, 18.1 eV, and 25.3 eV through high harmonic generation using UV drive pulses. The narrow bandwidth performance is demonstrated through angle-resolved photoemission measurements on various quantum materials.