Researchers at the Massachusetts Institute of Technology (MIT) Media Lab have developed a new imaging device that consists of a loose bundle of optical fibers; no lenses or protective housing are needed. Tight bundles of the fibers could yield endoscopes with narrower diameters.
The fibers of the new “optical brush” are connected to an array of photosensors at one end and left to wave free at the other. The fibers pass individually through micrometer-scale gaps in a porous membrane, providing images of the opposite side.
In experiments with their prototype system, the MIT researchers used a bundle of 1,100 fibers that were waving free at one end and positioned opposite a screen on which symbols were projected. The other end of the bundle was attached to a beam splitter, which was in turn connected to both an ordinary camera and a high-speed camera that distinguished optical pulses’ times of arrival.
Perpendicular to the tips of the fibers at the bundle’s loose end, and to each other, were two ultrafast lasers. The lasers fired short bursts of light, and the high-speed camera recorded their time of arrival along each fiber.
Because the bursts of light came from two different directions, software could use the differences in arrival time to produce a two-dimensional map of the positions of the fibers’ tips. The software then used that information to unscramble the jumbled image captured by the conventional camera.
“The primary advantage of this technology is that the end of the optical brush can change its form dynamically and flexibly,” said Keisuke Goda, a professor of chemistry at the University of Tokyo. “I believe it can be useful for endoscopy of the small intestine, which is highly complex in structure.”