Phase-locking of time-delayed attosecond XUV pulse pairs

Area of Science:

• Attosecond science
• Quantum optics
• Laser physics

Background:

• Precise control over ultrashort light pulses is crucial for investigating ultrafast phenomena.
• Generating synchronized extreme ultraviolet (XUV) pulses with attosecond precision presents significant technical challenges.

Purpose of the Study:

• To present a novel setup for generating phase-locked attosecond XUV pulse pairs.
• To demonstrate the capability for precise temporal control and high-resolution measurements using these pulse pairs.

Main Methods:

• Utilizing high harmonic generation (HHG) driven by two phase-locked near-infrared (NIR) pulses.
• Employing an actively stabilized Mach-Zehnder interferometer for generating phase-locked NIR pulses compatible with near-single cycle operation.
• Implementing XUV optical interferometry and XUV pump-NIR probe photoelectron spectroscopy for validation.

Main Results:

• Successfully generated phase-locked attosecond XUV pulse pairs with a tunable delay range of 400 fs.
• Achieved a delay jitter of less than 10 attoseconds (as).
• Validated the setup's precision and accuracy through interferometry and Rydberg state spectroscopy of helium.

Conclusions:

• The presented setup provides a robust platform for generating precisely controlled attosecond XUV pulse pairs.
• This capability opens new avenues for high-resolution pump-probe spectroscopy and fundamental studies in ultrafast science.
• The demonstrated sub-10-as delay jitter is critical for advanced time-resolved measurements.