US3700910A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bragg angle optical matched filter system with coded glass transmission plate
Assignee: United States Department of the Navy
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Filing: 1970-07-23
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Granted: 1972-10-24
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Expires: 1990-07-23
Abstract
Abstract The optical matched filter system provides a means of achieving pulse compression for pulse radar with an improved range resolution. The system separates zero and first order light at low frequencies (30-60MC region) by making use of the polarization properties of shear mode acoustic waves in quartz. Linear polarized collimated zero order light from a laser illuminates an acoustic modulator. An electrical signal is converted by transducers into an acoustic shear wave signal which is propagated through the acoustic modulator and modulates the laser light beam to generate first order light containing a coded phase front polarized orthogonal to the zero order light from the laser containing a plane phase front. When the first order coded phase front and a coded glass transmission plate are matched at the moment of correlation a first order plane phase front is produced. An analyzer blocks most of the zero order light to reduce the bias on a photomultiplier. The first order plane phase front is focused to a spot by a transform lens and the light is passed through an optimized aperture or slit to the photomultiplier where the optical output is converted to an electrical output.
Inventors
- 👤 Richard M Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:48
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/11; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/10; G01S13/26; G01S13/28; G01S13/284; G01S13/288
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
108 words
An optical matched filter system comprising: a source of linear polarized collimated zero order light having a frequency in the range of 30-60 mc.; a first means for generating a first order coded phase front polarized orthogonal to said zero order light when said zero order light impinges on said first means; a coded glass transmission plate means for producing a first order plane phase front from said first order coded front; polarized absorption type analyzer means to substantially block the passage of said zero order light, and; a transform lens means to focus only said first order plane phase front through an aperture and onto a photomultiplier.
Claim 2
Dependent Claim
108 words
An optical matched filter system comprising: a source of linear polarized collimated zero order light having a frequency in the range of 30-60 mc.; a first means for generating a first order coded phase front polarized orthogonal to said zero order light when said zero order light impinges on said first means; a coded glass transmission plate means for producing a first order plane phase front from said first order coded front; polarized absorption type analyzer means to substantially block the passage of said zero order light, and; a transform lens means to focus only said first order plane phase front through an aperture and onto a photomultiplier.
Claim 3
Dependent Claim
29 words
An optical matched filter system as recited in claim 6, wherein said first means is comprised of an ultrasonic light modulator means for producing an acoustic shear wave signal.
Claim 4
Dependent Claim
32 words
An optical matched filter system as recited in claim 2, wherein said ultrasonic light modulator means comprises a transducer to produce an acoustic shear wave signal which is propogated through fused silica.
Claim 5
Dependent Claim
39 words
An optical matched filter system as recited in claim 3 wherein a beam spreading prism means spreads out said zero order light in one dimension so it can interact over the entire length of said ultrasonic light modulator means.
Claim 6
Dependent Claim
27 words
An optical matched filter system as recited in claim 4, wherein a collimating lens is used with a spatial filter to produce said collimated zero order light.
Claim 7
Dependent Claim
132 words
An optical matched filter system for use in a pulse radar system comprising: first means for generating a linear polarized collimated zero order light having a frequency in the range of 30-60 mc. along a longitudinal axis; second means situated along said axis to spread said zero order light in one dimension; third means situated along said axis for intercepting said zero order light and generating a first order coded phase front polarized orthogonal to said zero order light; fourth means to produce a first order plane phase front from said first order coded phase front; fifth means to remove substantially all of said zero order light from said first order plane phase front; and, sixth means to focus said first order plane phase front through an aperture and onto a photomultiplier.
Claim 8
Dependent Claim
132 words
An optical matched filter system for use in a pulse radar system comprising: first means for generating a linear polarized collimated zero order light having a frequency in the range of 30-60 mc. along a longitudinal axis; second means situated along said axis to spread said zero order light in one dimension; third means situated along said axis for intercepting said zero order light and generating a first order coded phase front polarized orthogonal to said zero order light; fourth means to produce a first order plane phase front from said first order coded phase front; fifth means to remove substantially all of said zero order light from said first order plane phase front; and, sixth means to focus said first order plane phase front through an aperture and onto a photomultiplier.
Claim 9
Dependent Claim
17 words
The matched filter system of claim 6 wherein said third means comprises: a shear mode ultrasonic modulator.
Claim 10
Dependent Claim
17 words
The matched filter system of claim 7 wherein said fifth means comprises: a polarized absorption type analyzer.
Claim 11
Dependent Claim
17 words
The matched filter system of claim 8 wherein said fourth means comprises a coded glass transmission plate.
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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) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |