Quantitative Carré differential interference contrast microscopy to assess phase and amplitude

Area of Science:

• Biomedical optics
• Microscopy techniques
• Tissue optics

Background:

• Quantitative optical measurements of biological tissues are crucial for understanding their properties.
• Differential interference contrast (DIC) microscopy is widely used for imaging unstained specimens.
• Existing DIC methods often struggle to separate scattering and absorption effects.

Purpose of the Study:

• To develop a method for quantitative scatter and absorption measurement using an unmodified DIC microscope.
• To introduce a phase-stepping procedure for obtaining phase gradient information.
• To demonstrate the technique's capability in characterizing thin tissue samples.

Main Methods:

• Utilized an unmodified differential interference contrast microscope.
• Implemented a simple calibration process with a standard optical wedge.
• Developed a phase-stepping algorithm to isolate phase gradient information from absorption.

Main Results:

• Acquired quantitative data on scatter and absorption of thin tissue samples.
• Generated two-dimensional maps of local angular ray deviation (polar and azimuthal).
• Presented representative results for a porcine skin sample, demonstrating the method's efficacy.

Conclusions:

• The presented method allows for quantitative optical property assessment of thin tissues using standard DIC microscopy.
• The phase-stepping technique effectively separates phase information from absorption.
• This approach offers a valuable tool for non-invasive tissue characterization.