Work

A table-top few-femtosecond broadband extreme-ultraviolet absorption spectrometer with cryogenic cooling

Year: 2026

Type: article

Abstract: We present a table-top cryogenic ultrafast broadband extreme-ultraviolet absorption spectroscopy beamline designed for temperature-dependent and time-resolved investigations of quantum materials. The instrument combines a broadband high-harmonic generation source spanning 22-73 eV with automated image registration and cryogenic sample control down to 20 K, enabling element-specific measurements under both equilibrium and nonequilibrium conditions. The beamline provides sub-50-meV energy resolution and a routine 10-fs instrument response function, while maintaining long-term stability suitable for extended, ultrasensitive measurements. Benchmark experiments on NiI2, a van der Waals multiferroic, reveal temperature-dependent spectral evolution across its magnetic phase transitions, demonstrating the ability to identify element-specific contributions to the ground state and its transient response in the femtosecond regime. This instrument introduces the opportunity to unravel the very first response of a solid-state material during light-matter interaction, paving the way for understanding the complex phase space of nonequilibrium dynamics and emergent states in strongly correlated systems where the few-femtosecond electronic response has eluded most other types of time-resolved techniques.

Source: Review of Scientific Instruments

DOI: 10.1063/5.0350333