Large-scale optical lensless imaging with geometric fiber constructs

摘要

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, two- and 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.