Concentric spectrometer
First Claim
1. A spectrometer comprising:
- an entrance aperture through which an optical radiation signal is received;
an exit aperture; and
an optical system that is monocentric and has a dispersion element, and that directs said optical radiation signal along a non-direct optical path from said entrance aperture to said exit aperture via said dispersion element which disperses said optical radiation signal according to wavelength.
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Accused Products
Abstract
A concentric spectrometer which reduces stray light and re-entrant spectra within the spectrometer. The spectrometer includes a non-direct optical path between the entrance slit assembly and exit aperture. Dyson and Offner concentric optical configurations are used to eliminate third-order aberrations The concentric optical system includes a light trap which mitigates or eliminate stray light due to reflection of light incident on the exit aperture region but which does not impinge on the active area of a detector optically coupled to the exit aperture. A two-dimensional area array detector concurrently senses a spectral signal corresponding to an input optical radiation signal and a signal corresponding to zero-input radiation, and the spectral signal is corrected according to the zero-input radiation signal.
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Citations
68 Claims
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1. A spectrometer comprising:
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an entrance aperture through which an optical radiation signal is received;
an exit aperture; and
an optical system that is monocentric and has a dispersion element, and that directs said optical radiation signal along a non-direct optical path from said entrance aperture to said exit aperture via said dispersion element which disperses said optical radiation signal according to wavelength. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for correcting or compensating at least one spectral signal detected by a spectrometer which includes a two-dimensional detector, said method comprising the steps of:
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sensing with said two-dimensional detector said at least one spectral signal and at least one zero-input radiation signal, each of said at least one spectral signal representing dispersion according to wavelength by the spectrometer of a respective input optical radiation signal coupled into the spectrometer, said zero-input radiation signal sensed at all area of said two-dimensional detector exterior to any region that detects any said input optical radiation signal input into the spectrometer;
processing said optical radiation signal and said zero-input radiation signal to correct said optical radiation signal. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A spectrometer comprising:
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an entrance aperture through which a plurality of input optical radiation signals are concurrently received;
an exit aperture;
an optical system having a dispersion element, and which directs said plurality of input optical radiation signals along an optical path from said entrance aperture to said exit aperture via said dispersion element which spatially disperses each of said input optical radiation signals according to wavelength; and
a two-dimensional detector optically coupled to said exit aperture to detect at least a portion of each of said plurality of input optical radiation signals directed by said optical system to said exit aperture. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A spectrometer comprising:
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an entrance aperture through which an input optical radiation signal is received;
a detector;
a concentric optical system symmetric about an optical axis and having a dispersion element, and which directs said optical radiation signal along an optical path from said entrance aperture to said detector via said dispersion element which spatially disperses said optical radiation signal according to wavelength; and
a light trap disposed such that optical radiation is prevented from producing reflected light which interferes with optical signals detected by said detector. - View Dependent Claims (55, 56, 57, 58, 59, 60)
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61. A spectrometer comprising:
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an entrance slit assembly including an entrance slit and a plurality of optical fibers that each guide one of a respective plurality of input optical radiation signals into the spectrometer via the entrance slit;
a spherical plano-convex lens;
a concave diffraction grating having substantially parallel grooves, and having a common optical axis and substantially coincident center of curvature relative to said spherical plano-convex lens;
an exit aperture oriented such that said entrance aperture and said exit aperture are separated from and located on opposite sides of a plane which contains said optical axis and which is perpendicular to a direction along the parallel grooves of said concave diffraction grating, thereby providing a non-direct optical path between the entrance and exit apertures; and
a detector optically coupled to the exit aperture, and which senses a plurality of spectral signals each corresponding to one of the respective plurality of input optical signals directed by said spherical plano-convex lens to said concave diffraction grating, dispersed according to wavelength and directed to said spherical plano-convex lens by said diffraction grating, and directed by said spherical plano-convex lens to said exit aperture. - View Dependent Claims (62)
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63. A spectrometer comprising:
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an entrance slit assembly including an entrance slit and a plurality of optical fibers that each guide one or a respective plurality of input optical radiation signals into the spectrometer via the entrance slit;
a concave mirror;
a convex diffraction grating having substantially parallel grooves, and having a common optical axis and substantially coincident center of curvature relative to said concave mirror;
an exit aperture oriented such that said entrance aperture and said exit aperture are separated from and located on opposite sides of a plane which contains said optical axis and which is perpendicular to a direction along the parallel grooves of said convex diffraction grating, thereby providing a non-direct optical path between the entrance and exit apertures; and
a detector optically coupled to the exit aperture, and which senses a plurality of spectral signals each corresponding to one or the respective plurality of input optical signals directed by said concave mirror to said convex diffraction grating, dispersed according to wavelength and directed to said concave mirror by said convex diffraction grating, and directed by said concave mirror to said exit aperture. - View Dependent Claims (64)
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65. A spectrometer comprising:
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receiving means for receiving optical radiation into the spectroimeter;
transmitting means for transmitting an optical radiation spectrum according to wavelength of the optical radiation received by the receiving means;
means for directing said optical radiation along a non-direct optical path from said receiving means to said transmitting means and for dispersing said input optical radiation signal according to wavelength to generate the optical radiation spectrum; and
means for detecting at least a portion of said optical radiation spectnum transmitted by said transmitting means. - View Dependent Claims (66, 67, 68)
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Specification