Design of optical systems with toroidal curved detectors

We consider using toroidal curved detectors to improve the performance of imaging optical systems. We demonstrate that some optical systems have an anamorphic field curvature. We consider an unobscured reimaging three-mirror anastigmat as an example (f^'=960  mm, F/5.3, ω_x×ω_y=4°×4°). By assuming that the image is focused on a toroidal detector surface and performing reoptimization, it becomes possible to obtain a notable gain in the image quality-up to 40% in terms of the spot root mean square radius. Through analytic computations and finite-element analysis, we demonstrate that this toroidal shape can be obtained by bending of a thinned detector in a relatively simple setup.