Wolf phase tomography (WPT) of transparent structures using partially coherent illumination

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• 3D Reconstruction

Background:

• Diffraction tomography, proposed by Emil Wolf in 1969, uses coherent holographic imaging for 3D information extraction.
• The Wolf equations describe correlations in partially coherent fields, a concept crucial for understanding light propagation.

Purpose of the Study:

• To introduce Wolf phase tomography (WPT), a novel diffraction tomography method utilizing partially coherent fields.
• To develop a technique that decouples refractive index distribution from sample thickness and operates in the space-time domain.

Main Methods:

• WPT employs partially coherent illumination (spatially coherent ring source, temporally incoherent white light).
• Reconstruction is performed directly in the space-time domain, avoiding Fourier transformations.
• Quantitative phase imaging with controlled phase shifts is used to acquire data.

Main Results:

• Demonstrated WPT principle using microbeads, spermatozoa, and live neural cultures.
• Achieved 3D refractive index (RI) distribution reconstruction from three intensity measurements.
• Obtained RI sensitivity on the order of 10^-5.

Conclusions:

• WPT offers a high-throughput, simple method for 3D imaging of transparent, inhomogeneous objects.
• The technique is suitable for studying dynamic 3D events in living cells across multiwell plates.
• WPT successfully decouples refractive index from sample thickness, simplifying analysis.