We describe the design, construction, and application of what are believed to be the smallest fiber-optic probes used to date during imaging or diagnosis involving low-coherence interferometry (LCI). The probes use novel fiber-optic gradient-index (GRIN) lenses fabricated by a recently developed modified chemical-vapor-deposition (MCVD) process that avoids on-axis aberrations commonly marring MCVD-fabricated GRIN substrate. Fusing GRIN fiber lenses onto single-mode fiber yields automatically aligned all-fiber probes that insert into tissue through hypodermic needles as small as 31-gauge (inner diameter, 127 μm). We demonstrate the use of such probes with LCI by measuring microscopic brain motions <i>in vivo</i>.
© 2002 Optical Society of America
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(170.3340) Medical optics and biotechnology : Laser Doppler velocimetry
(170.4500) Medical optics and biotechnology : Optical coherence tomography
(170.4580) Medical optics and biotechnology : Optical diagnostics for medicine
William A. Reed, Man F. Yan, and Mark J. Schnitzer, "Gradient-index fiber-optic microprobes for minimally invasive in vivo low-coherence interferometry," Opt. Lett. 27, 1794-1796 (2002)