The outer layer of sensors is used to determine the angle at which the light is entering the fiber, which could be used to create 3-D images, says Sorin. The sensors are distributed evenly around the center of the fiber. If some sensors are collecting a large amount of photons, but adjacent ones are not, the researchers can determine at what angle the photons originate.
The work is a very clever demonstration of how fibers with multiple materials can be used for various applications, says Juan Hinestroza, a professor of fiber science and apparel design at Cornell University. “I believe it is just the first of many possible applications to come for this technology,” he says. Hinestroza suspects that these sorts of fibers could be weaved or knitted into fabrics to sense temperature, occupancy, and traffic in a room or terminal, or to detect the presence of traces of certain hazardous gases.
John Rogers, a professor of materials science and engineering at the University of Illinois Urbana-Champaign, says that the work falls into a “growing collection of reports that explore new and unusual, sometimes bio-inspired approaches to imaging,” which includes a spherical, eye-shaped camera previously developed by his group. “The ability of the fibers to be spread over large areas, in a flexible format, could create an important niche for this new imaging technology,” he says. However, Rogers adds, the fiber camera seems to be “a technology in search of a problem to solve.”
Sorin says that the next step for the MIT team is to build more layers of sensors inside the fiber, which can be used to re-create images with multiple colors. Adding more layers is doable but could be challenging. “As you put more layers inside the fiber, it becomes harder to keep the cross section uniform,” Sorin says. It will take some testing to determine the best parameters, such as the speed in which the fibers can be drawn, as well as the maximum length that can sustain the original orientation of the sensors.