US5262644A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Remote spectroscopy for raman and brillouin scattering
Assignee: Southwest Research Institute
•
Filing: 1992-12-16
•
Granted: 1993-11-16
•
Expires: 2012-12-16
Abstract
Abstract An apparatus and method for performing Raman and Brillouin spectroscopy remotely. A near-infrared laser is used to irradiate a sample of material to be analyzed. Optical fibers transmit incident radiation from a near-infrared radiation source to the sample, and transmit Raman and Brillouin scattered radiation from the sample to the detecting equipment. The incident radiation is carefully determined so as to avoid fluorescence and to limit optic fiber losses. The invention provides useful information with the use of an interferometer.
Inventors
- 👤 John F. Maguire
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:56
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/63; G01N21/65; G01N21/636; G01N2021/638; G01N2021/651; G01N2021/653; G01N2021/656
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
234 words
An apparatus for remotely performing a spectroscopic analysis of Brillouin and Raman scattered radiation from a sample of material, comprising: a near-infrared laser for providing incident radiation, wherein the wavelength of said incident radiation is within a range of wavelengths between a fluorescence limit and a fiber optics loss limit, such that said incident radiation has a wavelength sufficiently long to minimize fluorescence from a material to be analyzed and sufficiently short to minimize optical fiber losses; an input optical fiber for transmitting said incident radiation to a sample of material to be analyzed, wherein said input fiber is made from a low loss optical fiber; at least one collecting optical fiber for receiving Brillouin and Raman scattered radiation from said sample, wherein said at least one collecting fiber is made from low loss optical fiber, wherein said input optical fiber and said at least one collecting optical fiber are placed at a predetermined angle with respect to each other; an interferometer for receiving said scattered radiation from said at least one collecting fiber and for generating a fringe pattern representative of said scattered radiation over time; a solid state infrared detector for detecting said fringe pattern and for producing a time-domain electrical signal representing intensities of said fringe pattern; and a processing means for transforming said time-domain electrical signal into a frequency-domain electrical signal representing intensities of said scattered radiation at different wavenumbers.
Claim 2
Independent Claim
234 words
An apparatus for remotely performing a spectroscopic analysis of Brillouin and Raman scattered radiation from a sample of material, comprising: a near-infrared laser for providing incident radiation, wherein the wavelength of said incident radiation is within a range of wavelengths between a fluorescence limit and a fiber optics loss limit, such that said incident radiation has a wavelength sufficiently long to minimize fluorescence from a material to be analyzed and sufficiently short to minimize optical fiber losses; an input optical fiber for transmitting said incident radiation to a sample of material to be analyzed, wherein said input fiber is made from a low loss optical fiber; at least one collecting optical fiber for receiving Brillouin and Raman scattered radiation from said sample, wherein said at least one collecting fiber is made from low loss optical fiber, wherein said input optical fiber and said at least one collecting optical fiber are placed at a predetermined angle with respect to each other; an interferometer for receiving said scattered radiation from said at least one collecting fiber and for generating a fringe pattern representative of said scattered radiation over time; a solid state infrared detector for detecting said fringe pattern and for producing a time-domain electrical signal representing intensities of said fringe pattern; and a processing means for transforming said time-domain electrical signal into a frequency-domain electrical signal representing intensities of said scattered radiation at different wavenumbers.
Claim 3
Dependent Claim
23 words
The apparatus of claim 1, wherein the wavelength emitted by said near-infrared laser is in the range of 1.0 micrometers to 2.0 micrometers.
Claim 4
Dependent Claim
25 words
The apparatus of claim 1, wherein said input optical fiber and said at least one collecting optical fiber are made from a heavy metal fluoride.
Claim 5
Dependent Claim
13 words
The apparatus of claim 1, wherein fibers are made from a fluoride material.
Claim 6
Dependent Claim
25 words
The apparatus of claim 1, wherein said angle is fixed by means of a probe head that secures the unclad ends of said optical fibers.
Claim 7
Dependent Claim
12 words
The apparatus of claim 1, wherein said interferometer is a Fabry-Perot interferometer.
Claim 8
Dependent Claim
14 words
The apparatus of claim 1, wherein said laser is a yttrium aluminum garnet laser.
Claim 9
Dependent Claim
13 words
The apparatus of claim 1, wherein said laser is a kryton ion laser.
Claim 10
Dependent Claim
135 words
A Brillouin and Raman scattering method of analyzing materials, comprising the steps of: radiating a sample of the material to be analyzed, using near infrared radiation transmitted through a low loss fiber optic input tube; placing a receiving end of a low loss fiber optic output tube at a fixed and predetermined angle to said fiber optic input tube; collecting Brillouin and Raman scattered radiation scattered by said material in response to said radiating step, using said low loss fiber optic output tube; using an interferometer to generate a fringe pattern of said scattered radiation as a function of time; using a detector to generate a time-domain electrical signal representative of said fringe pattern; and transforming said time-domain electrical signal into a frequency-domain electrical signal representative of intensities of said scattered radiation at different wavenumbers.
Claim 11
Dependent Claim
135 words
A Brillouin and Raman scattering method of analyzing materials, comprising the steps of: radiating a sample of the material to be analyzed, using near infrared radiation transmitted through a low loss fiber optic input tube; placing a receiving end of a low loss fiber optic output tube at a fixed and predetermined angle to said fiber optic input tube; collecting Brillouin and Raman scattered radiation scattered by said material in response to said radiating step, using said low loss fiber optic output tube; using an interferometer to generate a fringe pattern of said scattered radiation as a function of time; using a detector to generate a time-domain electrical signal representative of said fringe pattern; and transforming said time-domain electrical signal into a frequency-domain electrical signal representative of intensities of said scattered radiation at different wavenumbers.
Claim 12
Dependent Claim
25 words
The method of claim 8, wherein said transforming step is performed with a computer programmed to perform a Fourier transform of said time-domain electrical signal.
Claim 13
Dependent Claim
20 words
The method of claim 9, further comprising the step of determining the width of the Rayleigh line at half height.
Claim 14
Dependent Claim
20 words
The method of claim 9, further comprising the step of determining the width of a Brillouin peak at half height.
Claim 15
Dependent Claim
24 words
The method of claim 9, further comprising the step of comparing the area of the Rayleigh peak to the area of a Brillouin peak.
Claim 16
Dependent Claim
35 words
The method of claim 9, further comprising the step of determining the distance between the zero shift from the wavelength of the incident radiation to the wavenumber corresponding to the maximum value of Brillouin peak.
Claim 17
Dependent Claim
55 words
The method of claim 9, wherein said material is part of a rotating device, and further comprising the step of placing stationary ends of said optic fiber input tube and said fiber optic output tube in proximity to ends of corresponding nonstationary fibers such that as the device rotates, the ends communicate with each other.
Claim 18
Dependent Claim
41 words
The method of claim 9, and further comprising the step of determining the temperature of said material by obtaining a spectrum of the scattered wavelengths and comparing the intensity of anti-Stokes and Stokes lines on a spectrum obtained by said detector.
References Cited (Backward Citations)
US3906241A
Cited
US4411525A
Cited
US4184171A
Cited
US4472052A
Cited
US4509212A
Cited
US4573761A
Cited
US4678277A
Cited
US4620284A
Cited
FR2571144A1
Cited
JPS61160046A
Cited
US4767219A
Cited
WO1987006011A1
Cited
US4867564A
Cited
US4856897A
Cited
US4802761A
Cited
US4781458A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-11-15 | 1997-05-17 | 1997-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-11-15 | 2001-05-17 | 2001-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-11-15 | 2005-05-17 | 2005-11-16 | $7700.00 | Window Closed / Lapsed |