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US 4,995,721 AGranted
Two-dimensional spectrometer
AssigneeIMO Industries, Inc.
InventorsRobert J. Krupa, R. Calvin Owen
Life of this patent
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AssigneeIMO Industries, Inc.
InventorsRobert J. Krupa, R. Calvin Owen
Estimating the term…
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.
A two-dimensional spectrometer, having an entrance aperture for admission of light along an optical path to a primary mirror via a secondary mirror, and for reflection as a collimated-light beam from said primary mirror to a two-dimensional dispersive optical device effectively normal to the collimated beam, said dispersive optical device producing a reflected cross-dispersed beam back via said primary and secondary mirrors to a focal plane which effectively includes said entrance aperture, and a two-dimensional detector array in said focal plane and with at least some of its detector elements optically adjacent said optical path and optically facing back-reflected two-dimensionally dispersed light.
A two-dimensional spectrometer, having an entrance aperture for admission of light along an optical path, a reflecting/correcting system comprising primary and secondary mirrors for twice folding said path and for producing from light on said path a collimated beam of twice-reflected light, a two-dimensional dispersive optical device effectively normal to the collimated beam, said dispersive optical device producing a reflected cross-dispersed beam back via said primary and second mirrors to a focal plane which effectively includes said entrance aperture, and a two-dimensional detector array in said focal plane and with at least some of its detector elements optically adjacent said optical path and optically facing back-reflected two-dimensionally dispersed light.
A wide-spectral range, flat field, double-pass spectrometer, comprising a telescope system having an external entrance pupil, and a two-dimensional dispersive optical system positioned at the external entrance pupil of said telescope system;
A spectrometer having an entrance aperture for admission of light along an optical path to a primary mirror via a secondary mirror, and for reflection as a collimated-light beam from said primary mirror to an echelle grating effectively normal to the collimated beam, said grating producing a reflected dispersed beam back via said primary and secondary mirrors to a focal plane which effectively includes said entrance aperture, a predisperser positioned to disperse light admitted on said path via said entrance aperture, said predisperser determining the spectral order of light admitted by said entrance aperture, and a single-dimensional multi-element detector array in said focal plane and optically facing at least a fraction of the back-reflected light.
Dependencies are inferred from the claim text.