Probing electron-atom collision dynamics in gas plasma by high-order harmonic spectroscopy

Area of Science:

• Plasma Physics
• Atomic and Molecular Physics
• Laser Spectroscopy

Background:

• Plasma is a complex medium with diverse collisional processes.
• Analyzing plasma radiation is crucial for understanding its properties and dynamics.
• Electron-atom collisions (EAC) significantly influence plasma behavior.

Purpose of the Study:

• To demonstrate high-order harmonic (HH) spectroscopy as a tool for probing EAC dynamics.
• To investigate EAC processes in laser-induced gas plasma using time-resolved HH spectroscopy.
• To correlate observed HH spectral features with specific collision dynamics.

Main Methods:

• Utilized high-order harmonic (HH) spectroscopy with an elliptically polarized pump and a time-delayed linearly polarized probe.
• Generated laser-induced gas plasma using argon and krypton.
• Recorded HH spectra by scanning time delays up to hundreds of picoseconds.

Main Results:

• Observed delay-dependent HH yields exhibiting three distinct regions: enhancement, suppression, and restoration.
• These spectral features serve as signatures of EAC processes.
• Demonstrated the sensitivity of HH spectroscopy to electron-atom collision dynamics.

Conclusions:

• High-order harmonic spectroscopy is an effective method for studying electron-atom collision dynamics in plasmas.
• The observed delay-dependent HH yield patterns provide insights into the complex collisional interactions.
• This technique offers a powerful approach for plasma characterization.