Pulse length variation causing spectral distortions in OPO-based hyperspectral coherent Raman scattering microscopy

Area of Science:

• Optics and Photonics
• Spectroscopy
• Microscopy

Background:

• Picosecond optical parametric oscillators (OPOs) are vital light sources for hyperspectral coherent Raman scattering (CRS) microscopy.
• Broad wavelength tunability of OPOs is essential for advanced imaging applications.
• Variations in OPO pulse length can impact the quality of spectroscopic data.

Purpose of the Study:

• To investigate the effect of OPO pulse length variations on hyperspectral CRS imaging.
• To develop a method for stabilizing OPO pulse length during wavelength tuning.
• To demonstrate the acquisition of normalized and reproducible hyperspectral CRS data.

Main Methods:

• Utilized picosecond optical parametric oscillators (OPOs) as pump sources.
• Performed hyperspectral coherent Raman scattering (CRS) microscopy.
• Developed and implemented a custom MATLAB-based control program to monitor and counteract pulse length changes.
• Acquired and compared hyperspectral data from pure substances and biological specimens.

Main Results:

• Significant distortions in CRS spectra were observed when OPO pulse length was not monitored during wavelength tuning.
• The custom MATLAB control program successfully counteracted pulse length variations.
• Normalized and reproducible hyperspectral CRS datasets were acquired using the developed control method.
• The method proved effective for both pure substances and biological samples.

Conclusions:

• Consistent monitoring and control of OPO pulse length are critical for reliable hyperspectral CRS microscopy.
• A MATLAB-based control system can effectively mitigate spectral distortions caused by pulse length variations.
• This approach enables the acquisition of high-quality, reproducible hyperspectral CRS data for scientific analysis.