Time-lens based hyperspectral stimulated Raman scattering imaging and quantitative spectral analysis

Area of Science:

• Biomedical Optics
• Spectroscopy
• Microscopy

Background:

• Stimulated Raman scattering (SRS) microscopy enables label-free chemical imaging.
• Existing SRS methods face limitations in speed and spectral resolution.
• Hyperspectral imaging provides rich chemical information but often requires slow acquisition.

Purpose of the Study:

• To demonstrate a novel hyperspectral SRS microscope with enhanced speed and sensitivity.
• To enable label-free chemical analysis of biological samples at the molecular level.
• To explore applications in live cell imaging and disease diagnostics.

Main Methods:

• Utilized spectral-transformed excitation with a synchronized time-lens source and tunable pump pulse.
• Implemented electronic modulation at 2.29 MHz for rapid hyperspectral stimulated Raman loss (SRL) image acquisition.
• Employed multivariate curve resolution analysis for spectral unmixing and component mapping.

Main Results:

• Achieved detection of dimethyl sulfoxide (DMSO) down to 28 mM with a 2 μs time constant.
• Acquired hyperspectral SRL images of prostate cancer cells.
• Successfully decomposed SRL images into concentration maps of CH₂ and CH₃ bonds.

Conclusions:

• The developed hyperspectral SRS microscope offers high sensitivity and speed for label-free imaging.
• The technique allows for detailed chemical analysis of biological samples, including cellular composition.
• This method holds significant potential for advancing live cell imaging and diagnostics by leveraging fingerprint Raman bands.