Raman optical activity by coherent anti-Stokes Raman scattering spectral interferometry

Area of Science:

• Spectroscopy
• Chiroptical methods
• Nonlinear optics

Background:

• Raman optical activity (ROA) is a powerful technique for determining molecular chirality.
• Traditional ROA measurements can be limited by weak signals and artifacts.
• Coherent anti-Stokes Raman scattering (CARS) offers high sensitivity but requires specialized approaches for chirality detection.

Purpose of the Study:

• To develop a novel method for measuring ROA with enhanced sensitivity and reduced artifacts.
• To enable direct determination of the sign and magnitude of optical active non-resonant background susceptibility.
• To improve the accuracy and reliability of CARS-based chiroptical spectroscopy.

Main Methods:

• Utilized coherent anti-Stokes Raman scattering (CARS) spectral interferometry.
• Amplified weak chirality-induced CARS signals through interference with a strong external reference CARS field.
• Employed Fourier transformation for signal extraction and analysis.

Main Results:

• Demonstrated a new technique termed interferometric coherent Raman optical activity (iCROA).
• Successfully measured CARS-ROA spectra with significantly reduced artifacts.
• Achieved direct determination of both the sign and magnitude of optical active non-resonant background susceptibility.
• Clearly distinguished broad offset artifacts from optical rotatory dispersion.

Conclusions:

• The developed iCROA method provides a robust approach for measuring ROA.
• This technique enhances sensitivity and minimizes artifacts in CARS-based chiroptical measurements.
• iCROA offers a valuable tool for molecular chirality studies.