Spectral focusing-based stimulated Raman scattering microscopy using compact glass blocks for adjustable dispersion

Area of Science:

• Coherent Raman Scattering Microscopy
• Spectroscopy
• Optical Physics

Background:

• Spectral focusing is crucial for enhancing spectral resolution in coherent Raman scattering (CRS) microscopy.
• Existing methods for tuning optical chirp (e.g., glass rods, gratings, prisms) are complex, time-consuming, and require difficult alignment.
• These limitations hinder the broader adoption of spectral focusing techniques in microscopy.

Purpose of the Study:

• To develop a simplified and rapid method for tuning optical chirp in stimulated Raman scattering (SRS) microscopy.
• To introduce a novel configuration utilizing adjustable-dispersion glass blocks for efficient chirp modulation.
• To demonstrate the practical utility and performance of this new method in biological imaging.

Main Methods:

• A novel SRS configuration employing compact, adjustable-dispersion TIH53 glass blocks was developed.
• Optical chirp was rapidly tuned by adjusting the height of the glass blocks, altering the path length and number of bounces.
• The system's signal-to-noise ratio and spectral resolution were characterized at various chirp values.
• Imaging was performed in both the C-H stretching region (MCF-7 cells) and the fingerprint region (prostate cores).

Main Results:

• Adjustable-dispersion glass blocks enabled rapid and convenient tuning of optical chirp with minimal realignment.
• The system demonstrated flexibility in modifying chirp values, impacting signal-to-noise ratio and spectral resolution.
• Successful imaging was achieved in biologically relevant spectral regions, showcasing the method's applicability.
• The new approach significantly simplifies and miniaturizes experimental setups for spectral focusing.

Conclusions:

• Adjustable-dispersion glass blocks offer an effortless way to modify optical chirp in SRS microscopy.
• This technique greatly enhances the usability and accessibility of spectral focusing for diverse imaging requirements.
• The developed method has the potential to significantly advance the application of CRS microscopy in various scientific fields.