Quantitative phase imaging through an ultra-thin lensless fiber endoscope.

Area of Science:

• Biomedical Optics
• Medical Imaging
• Biophysics

Background:

• Quantitative Phase Imaging (QPI) offers label-free morphology and biophysical data crucial for biomedicine.
• In vivo pathological diagnosis using QPI remains challenging due to limitations in current imaging probes.
• Existing multi-core fiber bundle (MCF) imaging is restricted to amplitude modalities, hindering QPI applications.

Purpose of the Study:

• To develop an ultra-thin, lensless microendoscope for in vivo quantitative phase imaging.
• To overcome the limitations of amplitude-based imaging in fiber optic probes.
• To enable high-resolution, label-free 3D imaging for pathological diagnosis.

Main Methods:

• Utilized an ultra-thin bare Multi-Core Fiber (MCF) for imaging.
• Implemented a computational lensless microendoscope design.
• Reconstructed incident complex light fields from far-field speckle patterns for digital refocusing.
• Validated quantitative phase reconstruction accuracy using phase targets and hydrogel beads.

Main Results:

• Achieved quantitative phase imaging with microscale lateral resolution and nanoscale axial sensitivity through an ultra-thin MCF.
• Demonstrated digital refocusing in multi-layer samples without mechanical movement.
• Successfully performed 3D imaging of human cancer cells via the fiber endoscope.

Conclusions:

• The developed computational lensless QPI microendoscope effectively images biological samples through ultra-thin MCFs.
• This technique overcomes previous limitations, enabling advanced in vivo pathological diagnosis.
• The findings suggest significant potential for widespread clinical applications in disease diagnosis.