various embodiments provide an optical system including a plurality of mirrors , each mirror having a rotational axis of symmetry ; and a detector configured to detect an image formed by the plurality of mirrors . the plurality of mirrors are configured to scan an object space along a first direction . the plurality of mirrors are configured and arranged so that a focal length of the plurality of mirrors along the first direction is greater than a focal length of the plurality of mirrors in a second direction perpendicular to the first direction so as to obtain a ratio of anamorphism greater than approximately 1 . 5 .