Boosting laboratory photoelectron spectroscopy by megahertz high-order harmonics

Abstract

Since the discovery of the photoelectric effect, photoelectron spectroscopy has evolved into the most powerful technique for studying the electronic structure of materials. Moreover, the recent combination of photoelectron experiments with attosecond light sources using high-order harmonic generation (HHG) allows direct observation of electron dynamics in real time. However, the efficiency of these experiments is greatly limited by space-charge effects at typically low repetition rates of photoexcitation. Here, we demonstrate HHG-based laboratory photoemission experiments at a photoelectron count rate of 1 × 10 5 electrons/s and characterize the main features of the electronic band structure of Ag(001) within several seconds without significant degradation by the space-charge effects. The combination of a compact HHG light source at megahertz repetition rates with the efficient collection of photoelectrons using time-of-flight spectroscopy may allow rapid investigation of electronic bands in a flexible laboratory environment and pave the way for an efficient design of attosecond spectroscopy and microscopy.

High Average Power Near‐Infrared Few‐Cycle Lasers

“…Furthermore, the high repetition rate of these systems enabled coincidence detection of fragments after strong‐field ionization at 0.4 MHz repetition rate and recording photoion‐photoion‐coincidence spectra of molecular fragments after inner‐shell XUV excitation . In future many more applications, such as photoelectron spectroscopy, coherent control in ionization and XUV microscopy approaches, will benefit from the increased average power of modern few‐cycle lasers and secondary sources in the XUV.…”

“…Such sources will reduce detrimental space‐charge effects in photoelectron experiments but also enable coincidence measurements with attosecond resolution in the future.…”

Spatio-spectral structures in high harmonic generation driven by tightly focused high repetition rate lasers

“…The short-associated Rayleigh range asks for short and dense gas targets. These high repetition rate XUV systems are of great interest for several applications, such as coincidence detection of ionization fragments [15] and photoemission spectroscopy [16].…”

Imaging Momentum–Space Two‐Particle Correlations at Surfaces

“…We comment briefly on a new DPE setup which uses a light source based on high harmonics generation in combination with a pair of time-of-flight spectrometers. [42][43][44]…”