Super-resolved coherent anti-Stokes Raman scattering microscopy by coherent image scanning

Area of Science:

• Optics and Photonics
• Microscopy
• Biomedical Imaging

Background:

• Coherent anti-Stokes Raman scattering (CARS) microscopy provides chemical specificity but is limited by diffraction.
• Super-resolution techniques are crucial for visualizing sub-cellular structures with high detail.
• Existing nonlinear microscopy super-resolution methods can be complex or require high excitation intensities.

Purpose of the Study:

• To enhance the spatial resolution of CARS microscopy beyond the diffraction limit.
• To introduce a phase-sensitive approach for super-resolution in CARS.
• To develop a simple and low-excitation intensity method for improved CARS imaging.

Main Methods:

• Implementation of phase-resolved image scanning microscopy (PRISM) with a CARS setup.
• Utilizing inline interferometry to resolve the complex electric field.
• Applying pixel reassignment based on phase information for super-resolution.

Main Results:

• Achieved up to a two-fold increase in spatial resolution compared to conventional CARS microscopy.
• Demonstrated enhanced contrast revealing the distribution of resonant and nonresonant scatterers.
• The method is compatible with standard forward-detected CARS setups.

Conclusions:

• Phase-resolved CARS microscopy offers a significant resolution enhancement.
• The technique provides additional contrast information for detailed sample analysis.
• This simple, low-intensity method is a valuable advancement for nonlinear microscopy.