RAMAN SPECTROMETER HAVING WAVELENGTH-SELECTIVE OPTICAL AMPLIFICATION
First Claim
1. An apparatus for obtaining a Raman spectrum from a sample, comprising in combination:
- a light source for producing photons impinging on said sample and having a first wavelength effective for generating Raman scattering photons having at least one second wavelength from said sample in response to the photons having a first wavelength;
a solid fiber optical amplifier for receiving photons from said sample and for selectively amplifying the photons having at least one second wavelength over the photons having a first wavelength;
a detector for receiving the selectively amplified wavelengths from said optical amplifier and for generating a signal therefrom; and
a signal processor for receiving the signal from said detector and for generating a Raman spectrum therefrom.
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Accused Products
Abstract
An apparatus and method for obtaining Raman spectra that are suitable for continuous real-time monitoring, utilizing the basic technique of Raman spectroscopy in cooperation with wavelength-selective optical amplification are described. The invention improves the detection sensitivity of conventional Raman spectroscopy by orders of magnitude by providing strong wavelength-selective optical amplification and narrowband detection of the intense driving laser and the weak Raman signal(s), thereby essentially eliminating the driving laser signal from the detector and detection electronics. The invention is effective for both Stokes and anti-Stokes Raman lines, and either where the incident laser wavelength is fixed and the Raman spectrum is recorded by analyzing the output of the fiber amplifier with a spectrometer, or where the detection wavelength is fixed and the Raman spectrum is recorded by tuning the wavelength of the laser.
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Citations
20 Claims
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1. An apparatus for obtaining a Raman spectrum from a sample, comprising in combination:
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a light source for producing photons impinging on said sample and having a first wavelength effective for generating Raman scattering photons having at least one second wavelength from said sample in response to the photons having a first wavelength; a solid fiber optical amplifier for receiving photons from said sample and for selectively amplifying the photons having at least one second wavelength over the photons having a first wavelength; a detector for receiving the selectively amplified wavelengths from said optical amplifier and for generating a signal therefrom; and a signal processor for receiving the signal from said detector and for generating a Raman spectrum therefrom. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for obtaining a Raman spectrum from a sample, comprising the steps of:
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producing photons impinging on the sample and having a first wavelength effective for generating Raman scattering photons having at least one second wavelength from the sample in response to the photons having a first wavelength; selectively optically amplifying the photons from the sample having at least one second wavelength over the photons having a first wavelength using a solid fiber optical amplifier; generating a signal from the wavelengths produced from said step of selectively optically amplifying the photons from the sample; and generating a Raman spectrum from the signal. - View Dependent Claims (11, 12, 13, 14, 16, 17, 18)
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15. (canceled)
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19. An apparatus for obtaining a signal from a sample, comprising in combination:
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a light source for producing photons impinging on said sample and having a first wavelength effective for generating fluorescence photons having at least one second wavelength from said sample in response to the photons having a first wavelength; a solid fiber optical amplifier for receiving photons from said sample and for selectively amplifying the photons having at least one second wavelength over the photons having a first wavelength; a detector for receiving the selectively amplified wavelengths from said optical amplifier and for generating an electrical signal therefrom; and a signal processor for receiving the electric signal from said detector and for generating a signal therefrom.
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20. A method for obtaining a signal from a sample, comprising the steps of:
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producing photons impinging on the sample and having a first wavelength effective for generating fluorescence photons having at least one second wavelength from the sample in response to the photons having a first wavelength; selectively optically amplifying the photons from the sample having at least one second wavelength over the photons having a first wavelength using a solid fiber optical amplifier; generating an electrical signal from the wavelengths produced from said step of selectively optically amplifying the photons from the sample; and generating a signal from the electrical signal.
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Specification