A fabric can be your new camera!!
Micrograph showing the cross-section of new optoelectronic fiber
Imagine a soldier's uniform made of a special fabric that allows him to look in all directions and identify threats that are to his side or even behind him. In work that could turn such science fiction into reality, Massachusetts Institute of Technology (MIT) researchers have developed light-detecting fibers that, when weaved into a web, act as a flexible camera. Fabric composed of these fibers could be joined to a computer that could provide information on a small display screen attached to a visor, providing the soldier greater awareness of his surroundings.
The researchers, led by Associate Professor Yoel Fink of the Department of Materials Science and Engineering (DMSE), emphasize that while such an application and others like it are still only dreams, work is rapidly progressing on developing fabrics capable of capturing images. In a recent issue of the journal Nanoletters, the team reported what it called a "significant" advance: using such a fiber web to take a rudimentary picture of a smiley face.
"This is the first time that anybody has demonstrated that a single plane of fibers, or 'fabric,' can collect images just like a camera but without a lens," said Fink, corresponding author of the Nanoletters paper. "This work constitutes a new approach to vision and imaging."
Our eyes are a great example of Nature's approach to imaging: they involve a highly sophisticated and localized organ made in part of a delicate lens. Technologists have mimicked this approach in cameras, telescopes and even microscopes.
But lenses of natural or man-made origin have a limited field of view, and are susceptible to damage, leading to the loss of the imaging or seeing capacity altogether. Optical fiber webs, in contrast, provide a distributed imaging capability provided by the entire surface of a fabric, which is in principle much more robust to damage and "blindness." If one area is damaged, other fibers can still function, extracting the image.
"We are saying, 'instead of a tiny, sensitive object [for capturing images], let's construct a large, distributed system,'" said Fink, who is also affiliated with MIT's Research Laboratory of Electronics (RLE), the Center for Materials Science and Engineering (CMSE) and Institute for Soldier Nanotechnologies (ISN).
"While the current version of these fabrics can only image nearby objects, it can still can see much farther than most shirts can," he added.
Nested Detection Layers
The new fibers, less than a millimeter in diameter, are composed of layers of light-detecting materials nested one within another.
Those layers include two rings of a semiconductor material that are light sensitive, each ring only 100 billionths of a meter across. Four metal electrodes contact each of the rings, extending along the length of the fiber, for a total of eight. Each semiconductor ring with its attached electrodes is in turn encased in rings of a polymer insulator that separate it from its neighbor.