# US 8,786,853 B2 · Monochromator having a tunable grating > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,853 B2 - Document ID: US8786853B2 - Status: Granted - Kind: B2 - Application number: 13/145,239 - Filed: 2010-01-22 - Published: 2011-12-08 - Granted: 2014-07-22 - Earliest claimed: 2009-01-22 - Assignees: Csem Centre Suisse D'Electronique Et De Microtechnique SA—Recherche Et DéVeloppement - Applicants: Maurizio Tormen; Stanley Ross; Robert Lockhart - Inventors: Maurizio Tormen; Stanley Ross; Robert Lockhart - Web page: https://patentgrep.com/patent/US8786853B2 ## CPC - G01J 3/1804: {Plane gratings} - G01J 3/02: Details - G01J 3/0237: {Adjustable, e.g. focussing} - G01J 3/32: Investigating bands of a spectrum in sequence by a single detector - G02B 5/1828: {having means for producing variable diffraction (controlling the direction of light by means of one or more diffracting elements G02B26/0808; acousto-optical elements G02F1/11, G02F1/33; electro- or magneto-optical diffraction G02F1/292, G02F1/2955)} - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A spectrometer includes: an entrance aperture, a collimator, intended to produce, from a light source, a collimated input light (5), a plurality of gratings arranged in a 2-D matrix, a plurality of detectors, and an exit aperture. ## Claims ### Claim 1 A spectrometer, comprising: an entrance aperture; a collimator intended to produce, from a light source, a collimated input light; a plurality of gratings; an exit aperture; and a plurality of detectors, wherein said gratings are tunable and arranged to form a 2D-matrix to diffract said collimated input light, each of said gratings producing a distinct collimated beam with a narrow band of wavelength and each single individual one of said detectors being associated with one corresponding single individual grating of said plurality of gratings and arranged to measure the intensity of said distinct collimated beam with a narrow band of wavelength produced by said grating. ### Claim 2 (depends on 1) The spectrometer of claim 1, wherein each grating of said plurality of gratings comprises a plurality of elongated beams being arranged parallel to each other along an axis x, the longitudinal axis of each of said beams being perpendicular to the axis x and the top of each beam forming a reflective flat surface, and the plurality of reflective flat surfaces defining planes arranged to be parallel and spaced by a distance d1, said distance d1 being tunable, and wherein said collimator is arranged for the collimated input light to be parallel to a plane P, said plane P being parallel to the longitudinal axis of the elongated beams and perpendicular to said reflective flat surfaces and the angle α between said collimated input light and the normal to the reflective flat surfaces being different from 0°. ### Claim 3 (depends on 2) The spectrometer of claim 2, further comprising: a plurality of optical fibres arranged in order to output the diffracted light diffracted by each of said gratings. ### Claim 4 (depends on 2) The spectrometer of claim 2, wherein said angle α is within the range [10°; 70°]. ### Claim 5 (depends on 3) The spectrometer of claim 3, wherein said angle α is within the range [10′; 70°]. ### Claim 6 (depends on 2) The spectrometer of claim 2, wherein said plurality of gratings is a plurality of step gratings. ### Claim 7 (depends on 3) The spectrometer of claim 3, wherein said plurality of gratings is a plurality of step gratings. ### Claim 8 (depends on 4) The spectrometer of claim 4, wherein said plurality of gratings is a plurality of step gratings. ### Claim 9 (depends on 5) The spectrometer of claim 5, wherein said plurality of gratings is a plurality of step gratings. ### Claim 10 (depends on 2) The spectrometer of claim 2, wherein said plurality of gratings is a plurality of blazed gratings. ### Claim 11 (depends on 3) The spectrometer of claim 3, wherein said plurality of gratings is a plurality of blazed gratings. ### Claim 12 (depends on 4) The spectrometer of claim 4, wherein said plurality of gratings is a plurality of blazed gratings. ### Claim 13 (depends on 5) The spectrometer of claim 5, wherein said plurality of gratings is a plurality of blazed gratings. ### Claim 14 (depends on 2) The spectrometer of claim 2, wherein each grating of said plurality of gratings comprises a first mirror intended to reflect back a first collimated beam with a narrow band of wavelength produced by said grating, the normal of said first mirror being parallel to said first collimated beam with a narrow band of wavelength, said grating diffracting again said first collimated beam with a narrow band of wavelength into a second collimated beam with a narrow band of wavelength, and said detector being arranged in order to measure the intensity of said second collimated beam with a narrow band of wavelength. ### Claim 15 (depends on 2) The spectrometer of claim 2, wherein said gratings are arranged in a plurality of pairs of gratings, each pair associating a first grating and a second grating, said pair further comprising a first mirror reflecting a first collimated beam with a narrow band of wavelength produced by said first grating onto said second grating, said second grating having reflective flat surfaces defining planes arranged to be parallel and spaced by a distance d2, producing a second collimated beam with a narrow band of wavelength, and wherein said pair is furthermore associated with a detector arranged to measure the intensity of said second collimated beam with a narrow band of wavelength. ### Claim 16 (depends on 15) The spectrometer of claim 15, wherein each pair of gratings furthermore comprises a second mirror reflecting back the second collimated beam with a narrow band of wavelength, the normal of said second mirror being parallel to the second collimated beam with a narrow band of wavelength, said pair of gratings diffracting said second collimated beam with a narrow band of wavelength after reflection on the second mirror. ### Claim 17 (depends on 15) The spectrometer of claim 15, wherein the distance d1 between two consecutive flat surfaces of the first grating is equal to the distance d2 between two consecutive flat surfaces of the second grating. ### Claim 18 (depends on 16) The spectrometer of claim 16, wherein the distance d1 between two consecutive flat surfaces of the first grating is equal to the distance d2 between two consecutive flat surfaces of the second grating. ### Claim 19 (depends on 15) The spectrometer of claim 15, wherein the distance d1 between two consecutive flat surfaces of the first grating is different from the distance d2 between two consecutive flat surfaces of the grating. ### Claim 20 (depends on 16) The spectrometer of claim 16, wherein the distance d1 between two consecutive flat surfaces of the first grating is different from the distance d2 between two consecutive flat surfaces of the grating. ### Claim 21 (depends on 1) The spectrometer of claim 1, further comprising: a first mirror and a second mirror, wherein each grating of said plurality of gratings comprises a plurality of elongated beams placed on a substrate, said elongated beams being arranged parallel to each other along an axis x, the longitudinal axis of each of said beams being perpendicular to the axis x and the distances e between two consecutive beams in the direction of x being equal and tunable, wherein the top of each beam comprises on a first longitudinal side, a first tilted reflective flat surface parallel to each first tilted surface of said elongated beams, and, on a second longitudinal side, a second tilted reflective flat surface, parallel to each second tilted surface of said elongated beams, wherein collimated input light is arranged to be parallel to a first plane, said first plane being parallel to the longitudinal axis of each of said beams and perpendicular to the first tilted reflective flat surfaces, said collimated input light being diffracted by said grating into a first collimated beam with a narrow band of wavelength, and wherein said first mirror and second mirror, are arranged in order for said first collimated beam with a narrow band of wavelength to be parallel to a second plane after reflection on the second mirror, said second plane being parallel to the longitudinal axis of each of said beams and perpendicular to the second tilted reflective flat surfaces, said first collimated beam with a narrow band of wavelength being diffracted by said grating into a second collimated beam with a narrow band of wavelength. ### Claim 22 (depends on 21) The spectrometer of claim 21, further comprising: a third mirror, said third mirror reflecting back the second collimated beam with a narrow band of wavelength, the normal of said third flat mirror being parallel to said second collimated beam with a narrow band of wavelength. ### Claim 23 A monochromator comprising: an entrance aperture; a collimator, intended to produce, from a light source, a collimated input light; a grating comprising a plurality of elongated beams placed on a substrate, said elongated beams being arranged parallel to each other along an axis x, the longitudinal axis of each of said beams being perpendicular to the axis x and the distances e between two consecutive beams in the direction of x being equal and tunable; an exit aperture; and a first mirror and a second mirror, wherein the top of each elongated beam comprises on a first longitudinal side, a first tilted reflective flat surface parallel to each first tilted surface of said elongated beams, and, on a second longitudinal side, a second tilted reflective flat surface, parallel to each second tilted surface of said elongated beams, and wherein said collimated input light is arranged to be parallel to a first plane, said first plane being oriented parallel to the longitudinal axis of each of said beams and perpendicular to the first tilted reflective flat surfaces, said collimated input light being diffracted by said grating into a first collimated beam with a narrow band of wavelength, and wherein said first mirror and second mirror, are arranged in order for said first collimated beam with a narrow band of wavelength to be parallel to a second plane after reflection on the second mirror, said second plane being parallel to the longitudinal axis of each of said beams and perpendicular to the second tilted reflective flat surfaces, said first collimated beam with a narrow band of wavelength being diffracted by said grating into a second collimated beam with a narrow band of wavelength, and wherein said detector is arranged to measure the intensity of the second collimated beam with a narrow band of wavelength produced by said grating. ### Claim 24 (depends on 23) A spectrometer, comprising: a monochromator according to claim 23; a detector; and a third flat mirror, said third flat mirror reflecting back the second collimated beam with a narrow band of wavelength, the normal of said third flat mirror being parallel to said second collimated beam with a narrow band of wavelength. ### Claim 25 (depends on 1) The spectrometer of claim 1, further comprising: a dispersive element arranged to separate spatially overlapping spectra of a diffracted collimated output light produced by at least one grating before said output light falls onto at least one detector. ### Claim 26 (depends on 25) The spectrometer of claim 25, wherein each grating of said plurality of gratings comprises a first mirror intended to reflect back a first collimated beam with a narrow band of wavelength produced by said grating, the normal of said first mirror being parallel to said first collimated beam with a narrow band of wavelength, said grating diffracting again said first collimated beam with a narrow band of wavelength into a second collimated beam with a narrow band of wavelength, and said detector being arranged in order to measure the intensity of said second collimated beam with a narrow band of wavelength. ### Claim 27 (depends on 25) The spectrometer of claim 25, wherein said gratings are arranged in a plurality of pairs of gratings, each pair associating a first grating and a second grating, said pair further comprising a first mirror reflecting a first collimated beam with a narrow band of wavelength produced by said first grating onto said second grating, said second grating having reflective flat surfaces defining planes arranged to be parallel and spaced by a distance d2, producing a second collimated beam with a narrow band of wavelength, and in that said pair is furthermore associated with a detector arranged to measure the intensity of said second collimated beam with a narrow band of wavelength. ### Claim 28 (depends on 25) The spectrometer of claim 25, wherein said dispersive element is a prism. ### Claim 29 (depends on 26) The spectrometer of claim 26, wherein said dispersive element is a prism. ### Claim 30 (depends on 27) The spectrometer of claim 27, wherein said dispersive element is a prism. ### Claim 31 (depends on 25) The spectrometer of claim 25, comprising a plurality of detectors arranged to form a 2D matrix of detectors. ### Claim 32 (depends on 26) The spectrometer of claim 26, comprising a plurality of detectors arranged to form a 2D matrix of detectors.