A tabletop femtosecond time-resolved soft x-ray transient absorption spectrometer

Area of Science:

• Atomic and Molecular Physics
• Ultrafast Spectroscopy
• X-ray Science

Background:

• Femtosecond laser systems enable probing ultrafast dynamics.
• Soft X-ray spectroscopy provides element-specific electronic structure information.
• Time-resolved studies are crucial for understanding chemical reaction mechanisms.

Purpose of the Study:

• To develop a tabletop instrument for femtosecond soft X-ray transient absorption spectroscopy.
• To achieve sub-50-femtosecond time resolution for probing atomic and molecular dynamics.
• To provide chemically specific insights into transient electronic structures.

Main Methods:

• Utilized high-order harmonic generation from a femtosecond Ti:sapphire laser.
• Employed a Ne-filled capillary waveguide for harmonic generation.
• Used a homebuilt soft X-ray spectrometer with toroidal mirrors, grating, and CCD camera for detection.
• Focused harmonics into a gas cell for pump-probe experiments with an optical pulse.

Main Results:

• Demonstrated a laser-based instrument for femtosecond soft X-ray transient absorption spectroscopy.
• Achieved sub-50-femtosecond time resolution for probing core-level absorptions.
• Presented static and time-resolved photoabsorption spectra of atoms and molecules.

Conclusions:

• The developed instrument offers a powerful tool for studying ultrafast dynamics in atoms and molecules.
• Chemically specific, time-resolved electronic structure information can be obtained with high temporal precision.
• This technique opens new avenues for investigating fundamental processes in chemistry and physics.