Attosecond electron spectroscopy using a novel interferometric pump-probe technique

Area of Science:

• Quantum Dynamics
• Attosecond Science
• Atomic Physics

Background:

• Characterizing electron wave packets (WPs) is crucial for understanding ultrafast quantum phenomena.
• Existing methods face limitations in spectral resolution for bound WPs.

Purpose of the Study:

• To present a novel interferometric pump-probe technique for characterizing attosecond electron wave packets.
• To measure bound WPs using a free WP as a reference.

Main Methods:

• Utilized an interferometric pump-probe setup.
• Excited helium atoms with an attosecond pulse (AP) to create simultaneous bound and free WPs.
• Ionized the bound WP with a synchronized few-cycle infrared laser.
• Measured delay-dependent photoelectron spectra to obtain an interferogram.

Main Results:

• The interferogram revealed quantum beats and multipath interference.
• Successfully determined bound WP components with high spectral resolution.
• Achieved spectral resolution superior to the inverse of the AP duration.

Conclusions:

• The developed technique offers enhanced spectral resolution for bound WP characterization.
• This method provides a new pathway for probing ultrafast electron dynamics.