High resolution time- and angle-resolved photoemission spectroscopy with 11 eV laser pulses

TL;DR

This paper introduces a novel 11 eV laser-based time- and angle-resolved photoemission spectroscopy setup that achieves high energy resolution, high photon flux, and operates at high repetition rates, enabling advanced studies of non-equilibrium band structures.

Contribution

The authors develop a compact 11 eV tr-ARPES system with unprecedented energy resolution of 16 meV and high photon flux, operable at 250 kHz, surpassing previous HHG-based setups.

Findings

Achieved 16 meV energy resolution in tr-ARPES.

Generated a flux of 5×10^{10} photons/sec.

Demonstrated capability on charge density wave material ErTe₃.

Abstract

Performing time and angle resolved photoemission spectroscopy (tr-ARPES) at high momenta necessitates extreme ultraviolet laser pulses, which are typically produced via high harmonic generation (HHG). Despite recent advances, HHG-based setups still require large pulse energies (hundreds of $\mu$J to mJ) and their energy resolution is limited to tens of meV. Here, we present a novel 11 eV tr-ARPES setup that generates a flux of $5\times10^{10}$ photons/s and achieves an unprecedented energy resolution of 16 meV. It can be operated at high repetition rates (up to 250 kHz) while using input pulse energies down to 3 $\mu$J. We demonstrate these unique capabilities by simultaneously capturing the energy and momentum resolved dynamics in two well-separated momentum space regions of a charge density wave material ErTe$_3$. This novel setup offers opportunity to study the non-equilibrium band structure of solids with exceptional energy and time resolutions at high repetition rates.