US4934816A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser absorption detection enhancing apparatus and method
Assignee: Southwest Sciences Inc
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Filing: 1988-05-18
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Granted: 1990-06-19
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Expires: 2008-05-18
Abstract
Abstract The disclosure relates to an apparatus and method for increasing the sensitivity of laser absorption detection of gas phase atoms and molecular species within a gaseous medium. An active optical element in a laser absorption detection system is translationally (longitudinally) vibrated a selected amplitude along the optical axis and at a desired frequency to eliminate fringes produced by interference fringe producing optical elements. The vibration frequency is preferably asynchronous with other modulation frequencies in the system.
Inventors
- 👤 Joel A. Silver
- 👤 Alan C. Stanton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:01
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/42; G01J3/433; G01J3/4338; G01J3/02; G01J3/0262; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/39; G01N21/01; G01N21/03; G01N21/031
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
117 words
In a system utilizing laser absorption for detecting gas phase atoms and molecular species within a gaseous medium, the system comprising a source for a laser beam, the coherence length of the laser source being at least equal to the distance between any fringe creating optical elements within the system, an apparatus for improving the detection sensitivity of the system by overcoming optical interference effects comprising: an active optical element disposed on an optical path in said system; means for generating, along said optical path, physical translational vibration within said active optical element; and means for controlling the amplitude and frequency of said vibration producing means to substantially eliminate fringes produced by the fringe producing optical elements.
Claim 2
Dependent Claim
117 words
In a system utilizing laser absorption for detecting gas phase atoms and molecular species within a gaseous medium, the system comprising a source for a laser beam, the coherence length of the laser source being at least equal to the distance between any fringe creating optical elements within the system, an apparatus for improving the detection sensitivity of the system by overcoming optical interference effects comprising: an active optical element disposed on an optical path in said system; means for generating, along said optical path, physical translational vibration within said active optical element; and means for controlling the amplitude and frequency of said vibration producing means to substantially eliminate fringes produced by the fringe producing optical elements.
Claim 3
Dependent Claim
13 words
The invention of claim 1 wherein said active optical element comprises a mirror.
Claim 4
Dependent Claim
13 words
The invention of claim 1 wherein said active optical element comprises a lens.
Claim 5
Dependent Claim
14 words
The invention of claim 1 wherein said vibration generating means comprises a piezoelectric transducer.
Claim 6
Dependent Claim
22 words
The invention of claim 1 wherein said controlling means comprises means for controlling amplitude between about one-quarter wavelength and about ten wavelengths.
Claim 7
Dependent Claim
28 words
The invention of claim 1 wherein said controlling means comprises means for controlling frequency between about 5 Hz and the upper vibrational limit of the vibration producing means.
Claim 8
Dependent Claim
27 words
The invention of claim 1 wherein said controlling means operates said translational vibration generating means at a frequency asynchronous to any other modulation frequency within the system.
Claim 9
Dependent Claim
52 words
The invention of claim 1 wherein said controlling means operate said translational vibration generating means to vibrate said active optical element a translational distance sufficient to cause a change in optical path length at least greater than one-quarter wavelength, equivalent to frequency tuning of at least one-half the fringe free spectral range.
Claim 10
Dependent Claim
27 words
The invention of claim 1 wherein said controlling means operates said translational vibration generating means to vibrate said active optical element a distance exceeding several beam wavelengths.
Claim 11
Dependent Claim
113 words
In a system utilizing laser absorption for detecting gas phase atoms and molecular species within a gaseous medium, the system comprising a source for a laser beam, the coherence length of the laser source being at least equal to the distance between any fringe creating optical elements within the system, the system comprising an optical path having an active optical element disposed therein, a method for improving the detection sensitivity of the system by overcoming optical interference effects comprising: generating, along the optical path, physical translational vibration within the active optical element; and controlling the amplitude and frequency of the vibration produced to substantially eliminate fringes produced by the fringe producing optical element.
Claim 12
Dependent Claim
113 words
In a system utilizing laser absorption for detecting gas phase atoms and molecular species within a gaseous medium, the system comprising a source for a laser beam, the coherence length of the laser source being at least equal to the distance between any fringe creating optical elements within the system, the system comprising an optical path having an active optical element disposed therein, a method for improving the detection sensitivity of the system by overcoming optical interference effects comprising: generating, along the optical path, physical translational vibration within the active optical element; and controlling the amplitude and frequency of the vibration produced to substantially eliminate fringes produced by the fringe producing optical element.
Claim 13
Dependent Claim
26 words
The method of claim 10 further comprising controlling the frequency of the vibration produced to be asynchronous to any other modulation frequency used in the system.
Claim 14
Dependent Claim
42 words
The method of claim 10 further comprising controlling the amplitude of the vibration produced to cause a change in the optical path length at least greater than one-quarter wavelength, equivalent to frequency tuning greater than one-half of the fringe free spectral range.
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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) | 1993-06-18 | 1993-12-18 | 1994-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-18 | 1997-12-18 | 1998-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-18 | 2001-12-18 | 2002-06-19 | $7700.00 | Window Closed / Lapsed |