Ultrafast photoemission momentum microscopy*

Understanding the electronic properties in material systems is key to unlocking new technologies. To probe the carrier dynamics on their natural timescale, ultrafast spectroscopies are employed, typically with femtosecond optical lasers. However, the observed features in these measurements are often ambiguous when attempting to identify the carriers involved and their location in the material band structure. Recent advances in ultrafast extreme-ultraviolet sources [1,2] now allow direct observation of carrier energy and momentum using angle-resolved photoelectron spectroscopy with the high data rates and low space-charge required for observing band structures. We demonstrate the capabilities when one of these XUV sources is paired with a time-of-flight momentum microscope [3] enabling time-resolved multidimensional measurements simultaneously spanning energy and two dimensions of momentum space.

1. Corder et. al. Structural Dynamics 5, 054301 (2018).
2. Mills et. al. Proc. of Conference on Lasers and Electro-Optics (OSA, 2017), p. STu1I.2.
3. Schönhense et. al. J. Electron Spectrosc. Relat. Phenom. 200, 94 (2015)