Multispectral time-resolved energy-momentum microscopy using high-harmonic extreme ultraviolet radiation

Area of Science:

• Condensed Matter Physics
• Ultrafast Spectroscopy
• Materials Science

Background:

• Time- and momentum-resolved photoemission spectroscopy (TR-PES) is crucial for understanding electronic dynamics.
• Previous methods often lacked the necessary resolution or were complex tabletop setups.

Purpose of the Study:

• To develop a high-resolution tabletop system for time- and momentum-resolved photoemission spectroscopy.
• To demonstrate three-dimensional (3D) Fermi surface mapping with unprecedented resolution.
• To enable studies of ultrafast dynamics in 3D electronic structures and molecular orbitals.

Main Methods:

• Utilized a 790-nm-driven high-harmonic generation source (6 kHz repetition rate).
• Integrated a toroidal-grating monochromator and a photoelectron time-of-flight momentum microscope.
• Achieved sub-100 femtosecond time resolution and high energy/momentum resolution (≲100 meV, ≲0.1 Å⁻¹).

Main Results:

• Successfully performed 3D Fermi surface mapping on graphene-covered Ir(111).
• Demonstrated time- and momentum-resolved photoemission spectroscopy across a 23.6–45.5 eV spectral range.
• Validated the capability for high-resolution measurements of electronic band structure and carrier dynamics.

Conclusions:

• The developed tabletop experiment provides a versatile platform for advanced electronic structure studies.
• This technique facilitates the investigation of kz-dependent ultrafast dynamics in 3D materials.
• Opens new avenues for studying ultrafast orbital dynamics in molecular systems.