US4666308A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for non-destructive testing using acoustic-optic laser probe
Assignee: Leland Stanford Junior University
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Filing: 1984-10-30
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Granted: 1987-05-19
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Expires: 2004-10-30
Abstract
Abstract Apparatus for non-destructively inspecting a material includes a housing for holding the material with a window in the housing for the transmission of a laser beam and a pressurized fluid within the housing in contact with the material. A first laser source generates a first beam at a first frequency, and the beam is directed through the window and onto said material. A second laser source generates a second beam at a second frequency, the second frequency being related to the first frequency whereby Bragg scattering of the second beam is realized in the pressurized fluid. The second beam is directed through the window and onto said material, and the Bragg scattered second beam is detected.
Inventors
- 👤 Clayton C. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:14
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/1702
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
139 words
Apparatus for non-destructively inspecting a material comprising a housing for holding said material and including window means in said housing for the transmission of an electromagnetic beam and including a fluid within said housing in contact with said material, a first electromagnetic source for generating a first electromagnetic beam modulated at a first frequency, means for directing said first electromagnetic beam through said window means and onto said material and generating acoustic waves in said fluid at said first frequency, a second electromagnetic source for generating a second electromagnetic beam at a second frequency, said second frequency being related to said first frequency whereby Bragg scattering of said second beam is realized in said fluid, means for directing said second electromagnetic beam through said window means and onto said material, and means for detecting said Bragg scattered second beam.
Claim 2
Dependent Claim
139 words
Apparatus for non-destructively inspecting a material comprising a housing for holding said material and including window means in said housing for the transmission of an electromagnetic beam and including a fluid within said housing in contact with said material, a first electromagnetic source for generating a first electromagnetic beam modulated at a first frequency, means for directing said first electromagnetic beam through said window means and onto said material and generating acoustic waves in said fluid at said first frequency, a second electromagnetic source for generating a second electromagnetic beam at a second frequency, said second frequency being related to said first frequency whereby Bragg scattering of said second beam is realized in said fluid, means for directing said second electromagnetic beam through said window means and onto said material, and means for detecting said Bragg scattered second beam.
Claim 3
Dependent Claim
65 words
Apparatus as defined by claim 1 wherein said first electromagnetic source comprises a first laser for generating said first beam at a modulation frequency of ω a , said second electromagnetic source comprising a second laser for generating said second beam having one mode at a frequency of ω o , said Bragg scattered second beam having a frequency of ω o +ω a .
Claim 4
Dependent Claim
38 words
Apparatus as defined by claim 2 wherein said means for detecting heterodynes said reflected beam having frequency of ω o +ω a with a signal at frequency ω o to obtain a signal at frequency ω a .
Claim 5
Dependent Claim
51 words
Apparatus as defined by claim 2 wherein said second beam includes a second mode at frequency ω o +ω r , said detector means including a first detector for obtaining a signal at the frequency ω r and a second detector for obtaining a signal at ω a -ω r .
Claim 6
Dependent Claim
111 words
Apparatus as defined by claim 4 wherein said means for detecting further includes means for mixing said signal at ω r with a lower frequency signal ω 1 and obtaining a signal frequency of ω r +ω 1 , means for mixing said frequency at ω r +ω 1 with said ω a signal and obtaining a signal at frequency of ω a +ω r +ω 1 , and mixer means for mixing said signal at ω a +ω r +ω 1 with said detected signal at ω a +ω r thereby obtaining a signal at ω 1 which is indicative of said acoustic wave, ω a , in said fluid.
Claim 7
Dependent Claim
17 words
Apparatus as defined by claim 1 wherein said fluid is chosen from argon gas and argon liquid.
Claim 8
Independent Claim
87 words
A method of non-destructive testing of material comprising the steps of placing said material in a fluid environment, energizing a surface of said material with a first electromagnetic wave modulated at freqiuency ω a thereby generating acoustic waves in said fluid, directing a second electromagnetic wave at a frequency ω o onto said surface, said frequency ω o being related to said frequency ω a whereby Bragg scattering and reflection of said second electromagnetic wave occurs in said fluid environment, and detecting the reflected second electromagnetic wave.
Claim 9
Independent Claim
87 words
A method of non-destructive testing of material comprising the steps of placing said material in a fluid environment, energizing a surface of said material with a first electromagnetic wave modulated at freqiuency ω a thereby generating acoustic waves in said fluid, directing a second electromagnetic wave at a frequency ω o onto said surface, said frequency ω o being related to said frequency ω a whereby Bragg scattering and reflection of said second electromagnetic wave occurs in said fluid environment, and detecting the reflected second electromagnetic wave.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-05-18 | 1990-11-17 | 1991-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-18 | 1994-11-17 | 1995-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-18 | 1998-11-17 | 1999-05-19 | $7700.00 | Window Closed / Lapsed |