Ultrafast time-domain spectroscopy system using 10 GHz asynchronous optical sampling with 100 kHz scan rate

Area of Science:

• Ultrafast spectroscopy
• Femtosecond laser systems
• Terahertz (THz) science

Background:

• Traditional time-domain spectroscopy systems often face limitations in scan speed and time-resolution.
• Achieving high signal-to-noise ratios in ultrafast measurements requires advanced techniques.
• Investigating ultrafast dynamics in molecular gases and coherent acoustic phonons demands precise temporal control.

Purpose of the Study:

• To present and evaluate an ultrafast time-domain spectroscopy system utilizing asynchronous optical sampling (ASOPS).
• To demonstrate the system's capability for high-speed data acquisition and high time-delay resolution.
• To showcase the system's application in THz time-domain spectroscopy and ultrafast pump-probe spectroscopy.

Main Methods:

• Implementation of an asynchronous optical sampling (ASOPS) system with a 10 GHz repetition rate.
• Utilization of two ultra-compact Ti:sapphire femtosecond ring lasers.
• Performance evaluation through THz time-domain spectroscopy on molecular gases and pump-probe spectroscopy of acoustic phonons.

Main Results:

• Achieved scan rates up to 100 kHz over a 100 ps time window with 100 fs time-delay resolution.
• Obtained signal-to-noise ratios exceeding 30 dB in millisecond averaging times for THz spectroscopy.
• Demonstrated high-sensitivity detection of coherent acoustic phonons with dephasing times within the 100 ps window.

Conclusions:

• The developed high-speed ASOPS system offers significant advantages for ultrafast spectroscopic studies.
• The system enables rapid and sensitive characterization of molecular dynamics and solid-state phenomena.
• This technology opens new avenues for investigating transient processes with unprecedented temporal precision.