Lens-free endoscopy probe for optical coherence tomography.

Area of Science:

• Biomedical Optics
• Medical Imaging Technology
• Fiber Optics Engineering

Background:

• Conventional optical coherence tomography (OCT) endoscopy probes often rely on bulky objective lenses, limiting miniaturization and flexibility.
• Developing smaller, more robust probes is crucial for minimally invasive diagnostic procedures and in vivo imaging.
• Existing fiber-optic probes may face challenges with beam quality and depth of field for effective OCT imaging.

Purpose of the Study:

• To design and fabricate an ultrathin, lens-free fiber-optic endoscopy probe for OCT.
• To achieve a larger depth of focus and side-viewing capability in an all-fiber probe.
• To demonstrate the practical applicability of the developed probe for OCT imaging.

Main Methods:

• Utilized a series of fused optical fibers, including a large-core fiber (20 μm) for the probe and a single-mode fiber (8.2 μm) for light delivery.
• Employed a bridge fiber of intermediate core size to stepwise convert guided light to a large mode-field diameter beam.
• Integrated a side-viewing capability by angling the fiber end, creating a 125 μm thick probe.

Main Results:

• Successfully fabricated an ultrathin, all-fiber endoscopy probe measuring 125 μm in thickness.
• Achieved a larger depth of focus due to the large mode-field diameter beam.
• Demonstrated successful OCT imaging using a swept-source OCT system with the lens-free probe.

Conclusions:

• The developed all-fiber endoscopy probe offers a compact and lens-free alternative for OCT imaging.
• The probe's design enhances imaging depth of field and provides side-viewing capabilities.
• This technology shows significant potential for advancing minimally invasive endoscopic OCT applications.