Chemical analysis and imaging by discrete fourier transform spectroscopy
First Claim
1. An optical sensor comprising:
- a plurality of monochromatic lightsources, each of said monochromatic lightsources producing light at a discrete wavelength, means for combining the light from said plurality of monochromatic lightsources into at least one light beam, said at least one light beam comprising a plurality of discrete wavelengths of light,an interferometer means for modulating said at least one light beam from said light source,means for directing said at least one light beam through a sample,a detector having means for detecting each of said plurality of discrete wavelengths of light in said at least one light beam after said at least one light beam has passed through said sample, said detector producing a detector signal indicative of the intensity of each of said plurality of discrete wavelengths of light in the detected light beam,and a signal processing means for analyzing said detector signal.
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Abstract
An instrument for chemical spectroscopy with imaging capabilities. A lightsource produces an array of light beams, each of which is made up of a plurality of discrete wavelengths. The array of light beams are modulated by an interferometer, then directed through a sample to an array of detectors. The sample may be a chemical mixture (e.g. a fuel stream in a manufacturing facility) or a body part (e.g. breast, limb, or head). An array of laser or light-emitting diodes provides light at the desired wavelengths and high intensity. The set of wavelengths is selected for a particular kind of analysis, and a specific set of possible absorbing species to be detected. The different wavelengths are guided optically (using fiber optics, lenses, and/or mirrors) into a single lightbeam, or an array of lightbeams. This light is then directed through the sample and onto a detector. The lightsource and detector, or lightsource alone, may be rastered if necessary to form an image. Individual lightbeams in an array may be modulated, polarized, or both so as to improve resolution. The signal from the detector undergoes a Fast Fourier Transform to produce a near-infrared absorption spectrum as a function of wavelength. The absorption spectra can be used to produce an image of the spacial distribution of detected species within the sample. Either the lightsource or detectors can be placed on the end of a probe or catheter for imaging through the wall of a hollow sample.
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Citations
27 Claims
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1. An optical sensor comprising:
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a plurality of monochromatic lightsources, each of said monochromatic lightsources producing light at a discrete wavelength, means for combining the light from said plurality of monochromatic lightsources into at least one light beam, said at least one light beam comprising a plurality of discrete wavelengths of light, an interferometer means for modulating said at least one light beam from said light source, means for directing said at least one light beam through a sample, a detector having means for detecting each of said plurality of discrete wavelengths of light in said at least one light beam after said at least one light beam has passed through said sample, said detector producing a detector signal indicative of the intensity of each of said plurality of discrete wavelengths of light in the detected light beam, and a signal processing means for analyzing said detector signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An optical sensor comprising:
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a plurality of monochromatic lightsource each of said monochromatic lightsources producing light at a discrete wavelength, means for combining the light from said plurality of monochromatic light sources into a two dimensional array of light beams, each of the light beams in said two dimensional array of light beams comprising a plurality of discrete wavelengths of light, an interferometer means for modulating said array of light beams from said light source, means for directing said array of light beams through a sample, a detector having means for detecting each of said plurality of discrete wavelengths of light in said array of light beams after said array of light beams has passed through said sample, said detector comprising a two dimensional array of broadband light detectors, said detector producing a detector signal indicative of the intensity of each of said plurality of discrete wavelengths of light in the detected array of light beams, and a signal processing means for analyzing said detector signal. - View Dependent Claims (21, 22, 23, 24, 25)
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26. An optical sensor comprising:
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a plurality of monochromatic lightsources, each of said monochromatic lightsources producing light at a discrete wavelength, means for combining the light from said plurality of monochromatic lightsources into a linear array of light beams, each of the light beams in said linear array of light beams comprising a plurality of discrete wavelengths of light, an interferometer means for modulating said linear array of light beams from said light source, means for directing said linear array of light beams through a sample, a detector having means for detecting each of said plurality of discrete wavelengths of light in said linear array of light beams after said linear array of light beams has passed through said sample, said detector producing a detector signal indicative of the intensity of each of said plurality of discrete wavelengths of light in the detected light beam, and a signal processing means for analyzing said detector signal. - View Dependent Claims (27)
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Specification