In-line ultra-thin attosecond delay line with direct absolute-zero delay reference and high stability.

Area of Science:

• Ultrafast optics
• Attosecond science
• Nonlinear optics

Background:

• Precise control of ultrashort laser pulses is crucial for attosecond science.
• Existing optical delay lines often face limitations in resolution and compactness.

Purpose of the Study:

• To introduce a novel, ultra-thin optical delay line with attosecond resolution.
• To enable advanced attosecond pump-probe spectroscopy.

Main Methods:

• Controlled wavefront division of femtosecond infrared pulses using micrometer-thin glass plates.
• Precise time delay control by rotating a glass plate, achieving attosecond resolution and stability.
• Interferometric self-calibration for performance validation.

Main Results:

• Demonstrated an ultra-thin optical delay line with 2.5 as to tens of attosecond resolution and 2 as stability.
• Validated performance by observing attosecond-resolved oscillations in high harmonic generation.
• Results agree with numerical simulations for a model atom.

Conclusions:

• The developed optical delay line offers unprecedented precision and compactness for attosecond experiments.
• This technology can be extended for future XUV-IR attosecond pump-probe experiments.
• The method provides a new tool for investigating ultrafast dynamics in matter.