Two-dimensional spectrometer

Abstract

A double-pass two-dimensional spectrometer utilizes a telescope wich contains only reflective optical components and is therefore free of chromatic aberrations. The telescope is so used in combination with dispersing optics as to allow double-pass use of the combination. The telescope has a state of correction such that, for example, an image which is diffraction-limited at 800 nm is produced over a flat field, corresponding to a wide-angle object coverage. This state of correction is accomplished with only two mirrors, one of which is a conic (e.g., hyperbolic) surface of revolution, while the other is a reflecting generalized polynomial aspheric corrector; and both mirrors are rotationally symmetric surfaces of revolution, each about its own axis of revolution. The double-pass nature of the system allows for a compact optical system consisting of only two reflecting surfaces, plus the dispersing optics, and there are no internal obscurations, thus avoiding negative effects of diffraction off of internal structures. The invention is shown for its applicability to each of several types of spectrometer-design configurations.