Polarized photoacoustic microscopy for vectorial-absorption-based anisotropy detection

Area of Science:

• Biomedical Optics
• Microscopy Techniques
• Materials Science

Background:

• Conventional photoacoustic microscopy assumes isotropic absorption.
• Microscopic anisotropy is crucial for understanding biological tissues and materials.
• Quantitative polarimetry methods are needed for advanced imaging.

Purpose of the Study:

• To introduce polarized photoacoustic microscopy (PPAM) for quantitative detection of microscopic anisotropy.
• To develop a novel parameter for quantifying anisotropic features.
• To demonstrate PPAM's capability in biological and material imaging.

Main Methods:

• Utilizing four linearly polarized laser beams as excitation sources.
• Measuring vectorial optical absorption to detect anisotropy.
• Developing a new parameter (0-1) to quantify anisotropy.
• Validating the method with dichroic phantoms and in situ imaging of mantis shrimp compound eyes.

Main Results:

• PPAM successfully quantifies microscopic anisotropy beyond optical absorption.
• The method was validated using dichroic phantoms.
• In situ 3D imaging of mantis shrimp compound eyes demonstrated PPAM's biological imaging capability.

Conclusions:

• PPAM offers an effective and straightforward strategy for tissue polarimetry.
• The technique has significant potential for advanced biological imaging.
• PPAM is also promising for material inspection applications.