Multiscale Modelling of Curved Pixel Arrays

Large format infrared (IR) detector arrays that provide high image resolution over a wide field of view (WFOV), are of critical importance for both defense and civilian applications, for example surveillance, astronomy, and remote sensing. Reduction of pixel pitch has been aggressively pursued to increase the array format, and the pixel dimension is approaching a size comparable to the wavelength. While significant progress has been made to increase the resolution of IR focal plane arrays (FPA), a considerable effort is still required to design the optics needed to implement the camera. For applications where a WFOV is needed, the camera optics has to be designed to mitigate the optical aberrations that degrade illumination and resolution uniformity across the FPA. This is currently achieved by employing many optical elements to flatten the Petzval field curvature to match the footprint of the planar image sensor. As a result of the complex optics needed to achieve field flattening, and at the same time to minimize other aberrations, the size, weight, and cost of the entire camera increases considerably.