High Repetition-Rate Femtosecond Stimulated Raman Spectroscopy with Fast Acquisition

TL;DR

This paper presents a high-repetition-rate femtosecond stimulated Raman spectroscopy setup that significantly reduces acquisition time and pulse energy, enabling faster and more efficient ultrafast vibrational studies.

Contribution

The authors develop a 200 kHz FSRS instrument with improved detection and artifact rejection, achieving faster data acquisition and lower laser pulse energy compared to traditional 1 kHz systems.

Findings

Achieves 3-6 fold reduction in pulse energy.

Attains 5-10 fold faster acquisition times.

Maintains good signal-to-noise performance.

Abstract

Time-resolved femtosecond stimulated Raman spectroscopy (FSRS) is a powerful tool for investigating ultrafast structural and vibrational dynamics in light absorbing systems. However, the technique generally requires exposing a sample to high laser pulse fluences and long acquisition times to achieve adequate signal-to-noise ratios. Here, we describe a timeresolved FSRS instrument built around a Yb ultrafast amplifier operating at 200 kHz, and address some of the unique challenges that arise at high repetition-rates. The setup includes detection with a 9 kHz CMOS camera and an improved dual-chopping scheme to reject scattering artifacts that occur in the 3-pulse configuration. The instrument demonstrates good signal-to-noise performance while simultaneously achieving a 3-6 fold reduction in pulse energy and a 5-10 fold reduction in acquisition time relative to comparable 1 kHz instruments.