Spectroscopic apparatus using spectrum narrowed and stabilized laser with Bragg grating
First Claim
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1. An apparatus for Raman spectroscopy of physical matter, the apparatus comprising:
- (a) a spectrum narrowed and stabilized laser element for generating a laser beam and for causing the laser beam to enter the physical matter to stimulate Raman scattering in the physical matter and thereby to produce a Raman signal, the spectrum narrowed and stabilized laser element comprising a laser chip and a Bragg grating attached directly onto the laser chip;
(b) at least one optical filter, disposed in a path of the Raman signal, for removing Rayleigh scattering from the Raman signal to produce a filtered Raman signal;
(c) an optical spectrometer, disposed in a path of the filtered Raman signal, for measuring the spectrum of the Raman signal and for generating a detection signal; and
(d) a microprocessor, connected to receive the detection signal, for determining properties of the physical matter from the detection signal.
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Abstract
An apparatus for measuring properties of physical matters by means of Raman spectroscopy including a laser element, a wavelength dispersion element, an array or single element detector, and a control and data processing unit. The laser element, which is used to excite Raman scattering, is spectrum narrowed and stabilized by attachment of a Bragg grating device. The grating can be either a volume Bragg grating (VBG) written inside a glass substrate or a fiber Bragg grating (FBG) written inside an optical fiber. A laser element can be provided with a wavelength modulation capability for fluorescence background suppression.
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Citations
48 Claims
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1. An apparatus for Raman spectroscopy of physical matter, the apparatus comprising:
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(a) a spectrum narrowed and stabilized laser element for generating a laser beam and for causing the laser beam to enter the physical matter to stimulate Raman scattering in the physical matter and thereby to produce a Raman signal, the spectrum narrowed and stabilized laser element comprising a laser chip and a Bragg grating attached directly onto the laser chip; (b) at least one optical filter, disposed in a path of the Raman signal, for removing Rayleigh scattering from the Raman signal to produce a filtered Raman signal; (c) an optical spectrometer, disposed in a path of the filtered Raman signal, for measuring the spectrum of the Raman signal and for generating a detection signal; and (d) a microprocessor, connected to receive the detection signal, for determining properties of the physical matter from the detection signal. - 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, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. An apparatus for Raman spectroscopy of physical matter, the apparatus comprising:
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(a) a Bragg grating enhanced super luminescence diode element for emitting light to be incident on the physical matter to stimulate Raman scattering in the physical matter and thereby to produce a Raman signal; (b) at least one optical filter, disposed in a path of the Raman signal, for removing Rayleigh scattering from the Raman signal to produce a filtered Raman signal; (c) an optical spectrometer, disposed in a path of the filtered Raman signal, for measuring the spectrum of the Raman signal and for generating a detection signal; and (d) a microprocessor, connected to receive the detection signal, for determining properties of the physical matter from the detection signal. - View Dependent Claims (42)
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43. A method for fluorescence suppression in Raman spectroscopy of a physical matter, comprising the steps of:
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(a) providing a multi-wavelength laser array by combining multiple Bragg grating enhanced lasers with different wavelengths to produce outputs, said different wavelengths being selected by using Bragg gratings having different grating periods; (b) shining the outputs of the lasers sequentially at certain frequency onto the physical matter to excite Raman scattering; (c) providing a Raman spectrometer to detect the excited Raman scattering and to generate a detection signal; and (d) amplifying/filtering the detection signal using a frequency selective amplification/filtering method tuned to said excitation frequency. - View Dependent Claims (44, 45, 46, 47, 48)
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Specification