Synthetic aperture interference light (SAIL) microscopy for high-throughput label-free imaging

Area of Science:

• Biomedical Optics
• Microscopy
• Quantitative Phase Imaging

Background:

• Quantitative phase imaging (QPI) is a label-free technique with broad biological and clinical applications.
• Existing QPI methods often face trade-offs between spatial resolution and field of view, limited by the space-bandwidth product.
• Computational phase retrieval algorithms used to overcome these limitations are time-consuming and prone to convergence issues.

Purpose of the Study:

• To introduce Synthetic Aperture Interference Light (SAIL) microscopy as a novel solution for high-resolution, wide field-of-view QPI.
• To address the limitations of existing QPI systems, including computational time and convergence problems.
• To demonstrate the capability of SAIL microscopy for label-free imaging of various biological specimens.

Main Methods:

• SAIL microscopy utilizes low-coherence interferometry to directly measure optical phase delay across different illumination angles.
• This approach enables the acquisition of large space-bandwidth product data without iterative phase reconstruction.
• The system achieves a synthetic numeric aperture of 0.45 and a field of view of 2.6 x 2.6 mm².

Main Results:

• SAIL microscopy successfully performed high-resolution, wide field-of-view label-free imaging.
• The technique was validated on standard samples and demonstrated in biomedical applications, including pathology slides, insects, and live cell cultures.
• Reconstructed images exhibited a synthetic numeric aperture of 0.45 and a field of view of 2.6 x 2.6 mm².

Conclusions:

• SAIL microscopy provides a direct phase measurement, eliminating the need for lengthy computational phase retrieval.
• The method is robust, always converges, and overcomes the limitations of space-bandwidth product in conventional QPI.
• SAIL microscopy presents a powerful tool for label-free imaging in diverse biological and medical research areas.