Spatially-coded Fourier ptychography: flexible and detachable coded thin films for quantitative phase imaging with...

Area of Science:

• Optical Imaging
• Microscopy
• Phase Contrast Imaging

Background:

• Fourier ptychography (FP) offers high-resolution complex-valued images but struggles with phase objects at specific spatial frequencies.
• This limitation stems from non-uniform phase transfer characteristics in conventional microscopy systems.
• Existing methods fail to recover linear phase ramps, hindering accurate phase imaging.

Purpose of the Study:

• To introduce a novel method, spatially-coded Fourier ptychography (scFP), for true quantitative phase imaging.
• To address the inherent phase transfer non-uniformity in FP and related techniques.
• To enhance reconstruction quality and correct refractive index underestimation.

Main Methods:

• Integration of a flexible, detachable coded thin film with a standard FP setup.
• The coded film introduces spatial modulation onto the image sensor.
• This spatial coding ensures uniform phase response across the synthetic bandwidth.

Main Results:

• scFP demonstrates improved reconstruction quality for phase objects.
• The method successfully corrects refractive index underestimation issues.
• Introduces measurement diversity in the spatial domain through coded detection.

Conclusions:

• scFP provides a robust solution for accurate quantitative phase imaging.
• The technique achieves a uniform frequency response, overcoming FP limitations.
• Expected to drive new research and applications in phase imaging requiring high quantitative accuracy.