Full-field quantitative phase and polarisation-resolved imaging through an optical fibre bundle

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Materials Science

Background:

• Conventional flexible optical fibres scramble phase and polarization, limiting imaging to amplitude information.
• This restricts applications in medical endoscopy and industrial inspection.

Purpose of the Study:

• To develop a method for accurate quantitative phase and polarization-resolved imaging using multi-core fibres (MCF).
• To overcome the limitations of amplitude-only imaging in flexible fibre optics.

Main Methods:

• Exploited the near-diagonality of the MCF transmission matrix in a parallelised fibre characterisation architecture.
• Measured and inverted the transmission matrix for accurate recovery of optical amplitude and phase in two polarizations.
• Applied a Bayesian inference approach to resolve 5 polarimetric properties of samples.

Main Results:

• Achieved accurate quantitative phase imaging with errors <0.3 rad.
• Obtained accurate polarization-resolved imaging with errors <10%.
• Generated high-resolution full-field images (9.0±2.6 µm for amplitude/phase, 36.0±10.4 µm for polarimetric) over a 750×750 µm² field-of-view at a 1mm working distance.

Conclusions:

• The developed method enables high-fidelity quantitative phase and polarization imaging through flexible MCFs.
• Demonstrated potential for computational image focusing using quantitative phase.
• Showcased the utility of polarization-resolved imaging for detecting sample birefringence.