Multimaterial photosensitive fiber constructs enable large-area optical sensing and imaging

The process of optical imaging and the use of a glass lens have been hitherto inseparable since it is the lens that is responsible for mapping incoming rays to form an image. While performing this critical role, the lens, by virtue of its geometry and materials composition, presents constraints on the size, weight, angular field of view, and environmental stability of an optical imaging system as a whole. Here, a new approach to optical imaging is presented. Tough polymeric light-sensing fibers are suspended on a frame to form large-scale, low-density, twoand three-dimensional photonic meshgrids. While a single grid can indeed locate a point of illumination, it is the stacking of a multiplicity of such grids, afforded by their essential transparency, which allows for the detection of the direction of illumination with a wide angular field of view. A surface-spanning-arrangement of such fibers is used to extract an arbitrary optical intensity distribution in a plane using a tomographic algorithm. Lensless imaging is achieved by a volumetric fiber assembly that extracts both the phase and intensity distributions of an incoming electromagnetic field, enabling one to readily determine the object from which the field originally emanated. The use of lenses for optical imaging has dominated optics since antiquity with no fundamental changes since, except for improvements in design and fabrication. The performance and size of any optical imaging system is usually determined by the quality and size of the lens(es) included in that system. The search for alternative approaches to optical imaging that do not rely on lenses, so-called lensless imaging, has had a venerable history. The common factor amongst all previous attempts is the introduction of a new optical system, usually an interferometer, which transforms the optical field before recording the intensity using a conventional opticaldetector array. A recent attempt demonstrated three-dimensional lensless imaging using a sophisticated interferometric arrangement and a novel computational algorithm [1]. In this paper we demonstrate a distinct, non-interferometric approach to lensless optical imaging that relies on a volumetric sampling of the electromagnetic field that is enabled by semitransparent 3D arrangements of photodetecting fibers. Photonics in the Transportation Industry: Auto to Aerospace II, edited by Alex A. Kazemi, Bernard C. Kress Proc. of SPIE Vol. 7314, 73140H · © 2009 SPIE · CCC code: 0277-786X/09/$18 · doi: 10.1117/12.821209 Proc. of SPIE Vol. 7314 73140H-1 Downloaded from SPIE Digital Library on 15 Mar 2010 to 18.51.1.125. Terms of Use: http://spiedl.org/terms