Investigation of gold-coated bare fiber probe for in situ intra-vitreous coherence domain optical imaging and sensing

Abstract

We have investigated the usage of gold-plated bare fiber probes for in situ imaging of retinal layers and surrounding ocular tissues using time-domain common-path optical coherence tomography. The fabricated intra-vitreous gold-plated micro-fiber probe can be fully integrated with surgical tools working in close proximity to the tissue to provide subsurface images having a self-contained reference plane independent to the Fresnel reflection between the distal end of the probe and the following medium for achieving reference in typical common-path optical coherence tomography. We have fully characterized the probe in an aqueous medium equivalent to the vitreous humor in the eye and were able to differentiate various functional retinal tissue layers whose thickness is larger than the system's resolution.

Fig. 1

Schematic of in situ frog retina imaging using common-path optical coherence tomography with gold-coated micro-fiber optic probe: (a) experimental setup; (b) gold-coated fiber probe (d: distance from the fiber probe to the sample, D: beam diameter determined by beam waist ω(d) at distance d). Microscope images of gold-coated probe (bottom left) and beam profile (bottom right)

Fig. 2

Optical performance of the probe in the aqueous environment: (a) effect of deposition time on reference peak level; (b) relative reflectance vs. deposition time in water

Fig. 3

A-mode (depth) scan images of reference signal: (a) thick (25 s deposition) coated probe in air; (b) thick (25 s deposition) coated probe in water; (c) thin (10 s deposition) coated probe in air; (d) thin (10 s deposition) coated probe in water

Fig. 4

Scanned false color OCT images of retina and other ocular tissues obtained from frog eye: (a) retina; (b) sclera