US4269509A
Expired / Lapsed
US
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Photoacoustic Raman spectroscopy
Assignee: Honeywell International Inc
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Filing: 1979-05-02
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Granted: 1981-05-26
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Expires: 1999-05-02
Abstract
Abstract A method and apparatus for spectroscopic material analysis are provided. Two coherent beams of monochromatic radiation are directed through a sample of material. A tuning mechanism adjusts the frequency difference between the radiation beams to equal substantially the vibrational frequency of a preselected constituent of the material. Molecular energy of a preselected constituent of the material is increased, thereby producing a detectable signal in the form of a pressure wave. The signal is received by a detecting mechanism which indicates the magnitude thereof.
Inventors
- 👤 Michael J. Berry
- 👤 Joseph J. Barrett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:01
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/44
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
108 words
Apparatus for analyzing material, comprising: a. radiation source means for generating two coherent beams or monochromatic light; b. tuning means for adjusting the frequency difference between said beams of radiation to equal substantially the vibrational frequency of a preselected constituent of said material; c. projecting means for directing said beams of light through said material to increase molecular energy of a preselected species of said material and thereby produce a detectable signal in the form of a pressure wave; d. detecting means for indicating the magnitude of said signal, said detecting means including a variable frequency bandwidth amplifier adjusted to transmit preselected acoustic frequencies of said pressure wave.
Claim 2
Dependent Claim
108 words
Apparatus for analyzing material, comprising: a. radiation source means for generating two coherent beams or monochromatic light; b. tuning means for adjusting the frequency difference between said beams of radiation to equal substantially the vibrational frequency of a preselected constituent of said material; c. projecting means for directing said beams of light through said material to increase molecular energy of a preselected species of said material and thereby produce a detectable signal in the form of a pressure wave; d. detecting means for indicating the magnitude of said signal, said detecting means including a variable frequency bandwidth amplifier adjusted to transmit preselected acoustic frequencies of said pressure wave.
Claim 3
Dependent Claim
24 words
Apparatus as recited in claim 1, wherein said tuning means is adjusted to selectively populate a higher energy level of said preselected molecular species.
Claim 4
Dependent Claim
22 words
Apparatus as recited in claim 1, wherein said projecting means is adjusted to effect spatial and temporal overlap between said radiation beams.
Claim 5
Dependent Claim
48 words
Apparatus as recited in claim 1, wherein said radiation source means comprises a dye laser including a dye cell containing a dye material, means for exciting said dye and a laser cavity comprising an optical element and a partially transmitting output mirror for generating and transmitting laser radiation.
Claim 6
Dependent Claim
26 words
Apparatus as recited in claim 4, wherein said dye material emits radiation upon being excited, said radiation having frequencies within the transparency range of said material.
Claim 7
Dependent Claim
33 words
Apparatus as recited in claim 1, wherein said tuning means comprises beam splitting means for separating said radiation into a pair of radiation beams, and a pair of diffraction gratings mounted in autocollimation.
Claim 8
Dependent Claim
16 words
Apparatus as recited in claim 1, wherein said first and second beams are counter-propagating and collinear.
Claim 9
Dependent Claim
26 words
Apparatus as recited in claim 1, including multipass means for directing said beams of light through said material, whereby the magnitude of said signal is increased.
Claim 10
Dependent Claim
24 words
Apparatus as recited in claim 8, wherein said multipass means causes said beams of light to pass through said material up to 30 times.
Claim 11
Independent Claim
73 words
A method for spectroscopically analyzing material comprising the steps of: a. generating two coherent beams of monochromatic radiation; b. adjusting the frequency difference between the beams of radiation to equal substantially the vibrational frequency of a preselected constituent of said material; c. directing the beams of radiation through the material in multiple passes to produce a detectable signal in the form of a pressure wave; and d. indicating the intensity of said signal.
Claim 12
Independent Claim
73 words
A method for spectroscopically analyzing material comprising the steps of: a. generating two coherent beams of monochromatic radiation; b. adjusting the frequency difference between the beams of radiation to equal substantially the vibrational frequency of a preselected constituent of said material; c. directing the beams of radiation through the material in multiple passes to produce a detectable signal in the form of a pressure wave; and d. indicating the intensity of said signal.
Claim 13
Dependent Claim
23 words
A method as recited in claim 10, wherein said material is selected from the group consisting of gases, liquids, solids and mixtures thereof.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-05-25 | 1984-11-24 | 1985-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-25 | 1988-11-24 | 1989-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-25 | 1992-11-24 | 1993-05-26 | $7700.00 | Window Closed / Lapsed |