Curved Focal Plane Array for Hyperspectral Imaging System

Prior work has demonstrated that curved focal plan arrays (FPA) enable lenses for traditional cameras with improved image quality and fewer elements as compared to existing flat image planes. There is an increasing interest in the development of curved focal planes for other imaging applications using a variety of surface contours. In this work, the potential performance improvements of a hyperspectral imaging system (HSI) with a curved FPA are explored using Corning's existing hyperspectral designs. We evaluated the effect of curved FPAs for spectrometers from the free-space and monolithic Offner class as well as the Dyson form. While these designs are already optimized with aspheric mirrors, the addition of the curved FPA provided additional performance improvements. Surface types considered for the FPA include aspheric, toroidal, anamorphic and free-forms. All of these FPA surface types are manufacturable. The surfaces providing optimum performance offer guidelines for future curved FPA development. We found that multiple design parameters, such as size, weight, f-number, field of view and relative cost can be improved compared with current state-of-the-art flat FPAs. A free-space Offner spectrometer, for example, can be reduced 30% in size, or improved by 20% in f-number.