Adaptive optics for enhanced signal in CARS microscopy

Area of Science:

• Biomedical Optics
• Microscopy
• Spectroscopy

Background:

• Label-free deep tissue imaging is crucial for in vivo and in situ biomedical applications.
• Coherent Anti-Stokes Raman Scattering (CARS) microscopy offers molecular vibrational contrast but is limited by penetration depth and signal degradation due to aberrations.
• Aberrations from both the optical system and biological tissues significantly reduce CARS signal intensity and image quality at depth.

Purpose of the Study:

• To develop and demonstrate an adaptive optics system integrated with CARS microscopy for enhanced deep tissue imaging.
• To correct for system and sample-induced aberrations to improve CARS signal intensity and penetration depth.
• To evaluate the performance of the combined system in test samples and biological tissue.

Main Methods:

• Integration of adaptive optics, specifically a deformable membrane mirror, with a CARS microscopy setup.
• Utilized a random search optimization algorithm to actively correct aberrations.
• Performed imaging and signal enhancement measurements in test samples and ex vivo muscle tissue at various depths.

Main Results:

• Adaptive optics successfully corrected for system and sample-induced aberrations.
• Achieved an average signal enhancement of approximately 3x in test samples at 700 microm depth.
• Demonstrated an average signal enhancement of approximately 6x in muscle tissue at 260 microm depth.

Conclusions:

• Adaptive optics significantly improves CARS signal intensity and image quality in deep tissues.
• The combined system overcomes the limitations of traditional CARS microscopy for deep tissue imaging.
• This enhanced CARS microscopy approach holds great potential as an in vivo and in situ biomedical imaging modality.