A quantitative comparison of time-of-flight momentum microscopes and hemispherical analyzers for time- and angle-resolved photoemission spectroscopy experiments

TL;DR

This study compares time-of-flight momentum microscopes and hemispherical analyzers in time- and angle-resolved photoemission spectroscopy, highlighting their complementary strengths and limitations for advanced electronic structure investigations.

Contribution

It provides a systematic experimental comparison of two detection schemes within the same setup, demonstrating their combined utility for comprehensive trARPES studies.

Findings

Momentum microscope offers higher detection efficiency.

Hemispherical analyzer provides better depth of focus.

Both instruments are complementary for different experimental needs.

Abstract

Time-of-flight-based momentum microscopy has a growing presence in photoemission studies, as it enables parallel energy- and momentum-resolved acquisition of the full photoelectron distribution. Here, we report table-top extreme ultraviolet (XUV) time- and angle-resolved photoemission spectroscopy (trARPES) featuring both a hemispherical analyzer and a momentum microscope within the same setup. We present a systematic comparison of the two detection schemes and quantify experimentally relevant parameters, including pump- and probe-induced space-charge effects, detection efficiency, photoelectron count rates, and depth of focus. We highlight the advantages and limitations of both instruments based on exemplary trARPES measurements of bulk WSe2. Our analysis demonstrates the complementary nature of the two spectrometers for time-resolved ARPES experiments. Their combination in a single experimental apparatus allows us to address a broad range of scientific questions with trARPES.