Frequency-modulation stimulated Raman scattering microscopy with an acousto-optic tunable filter

Area of Science:

• Biomedical Optics
• Microscopy Techniques
• Spectroscopy

Background:

• Stimulated Raman scattering (SRS) microscopy enables label-free, high-speed bioimaging.
• SRS is limited by spurious background signals that reduce imaging contrast and sensitivity.
• Frequency-modulation (FM) SRS suppresses background by exploiting spectral differences.

Purpose of the Study:

• To propose and demonstrate a novel FM-SRS scheme using an acousto-optic tunable filter.
• To improve background suppression and enhance imaging performance in SRS microscopy.
• To enable automated spectral measurements across a wide vibrational range.

Main Methods:

• Implementation of an FM-SRS system with an acousto-optic tunable filter.
• Probing spectral regions from the fingerprint to the CH-stretching range.
• Utilizing all-electronic control for spectral separation and intensity adjustments.

Main Results:

• The proposed FM-SRS scheme effectively suppresses background signals.
• Automated measurements are achievable without manual optical adjustments.
• The system allows precise electronic control over spectral parameters.

Conclusions:

• The acousto-optic tunable filter-based FM-SRS scheme offers significant advantages for bioimaging.
• This method enhances sensitivity and contrast in label-free SRS microscopy.
• The automated and electronically controlled nature simplifies operation and expands applicability.