Super-achromatic monolithic microprobe for ultrahigh-resolution endoscopic optical coherence tomography at 800\u2009nm

Wu Yuan,Robert Brown,Wayne Mitzner,Lonny Yarmus,Xingde Li

doi:10.1038/s41467-017-01494-4

Wu Yuan, Robert Brown + Show 3 more

Open Access

https://doi.org/10.1038/s41467-017-01494-4

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Abstract

Endoscopic optical coherence tomography (OCT) has emerged as a valuable tool for advancing our understanding of the histomorphology of various internal luminal organs and studying the pathogenesis of relevant diseases. To date, this technology affords limited resolving power for discerning subtle pathological changes associated with early diseases. In addition, it remains challenging to access small luminal organs or pass through narrow luminal sections without potentially causing trauma to tissue with a traditional OCT endoscope of a 1-1.5 mm diameter. Here we report an ultracompact (520 µm in outer diameter and 5 mm in rigid length) and super-achromatic microprobe made with a built-in monolithic fiber-optic ball lens, which achieves ultrahigh-resolution (1.7 µm axial resolution in tissue and 6 µm transverse resolution) for endoscopic OCT imaging at 800 nm. Its performance and translational potential are demonstrated by in vivo imaging of a mouse colon, a rat esophagus, and small airways in sheep.

Highlights

In recent years, optical coherence tomography (OCT) endoscopy at 800 nm has attracted increasing attention due to the unique possibility of achieving higher resolution and potentially better imaging contrast[12,13,14]
The microprobe consists of a home-made fiber ball lens and a short piece of multi-mode fiber (MMF) as a spacer spliced to a single-mode fiber (SMF)
It was found that a shorter working distance can be achieved with a longer MMF, and the focused spot size decreased with the increase of the MMF length

Summary

Introduction

OCT endoscopy at 800 nm has attracted increasing attention due to the unique possibility of achieving higher resolution (that is, < 3 μm versus conventional approximately 10 μm in air) and potentially better imaging contrast[12,13,14]. Our group has demonstrated that chromatic aberration can be significantly mitigated by using diffractive optics in OCT catheters[13,14]. Further miniaturization can be achieved by using an all-fiber monolithic catheter design, which employs an angle polished GRIN fiber-tip as a beam reflector[12,15]. Such a GRIN fiber-based catheter inherits the severe chromatic aberration at 800 nm the same as the traditional GRIN lens-based catheters. We demonstrate a super-achromatic, ultracompact microprobe made of a built-in monolithic fiber-optic ball lens and beam reflector. To demonstrate the flexibility and the translational potential of the microprobe for imaging small lumens within complex internal organs, in vivo a Reflective surface (47°)

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