US4038647A
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Method for holographic storage
Assignee: United States Department of the Navy
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Filing: 1976-02-18
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Granted: 1977-07-26
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Expires: 1996-02-18
Abstract
Abstract A method of improving the holographic storage of data by yielding brighterolograms with higher densities which comprises recording an interferogram of an object wave and a reference wave into a holographically recordable medium consisting of an ionic crystal initially with a random distribution of anisotropic centers, and mutually off-set at an angle of at least sin.sup. -1 10λ/d wherein d is the crystal thickness and λ the wavelength of the coherent source; and then consecutively exposing the crystal to the object wave and the reference wave, each with a π/2 rotation in the plane of polarization but without any change in light intensity, wavelength, or crystal temperature.
Inventors
- 👤 Irwin Schneider
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:00
CPC Classifications
G; G11; G11C; G11C13/00; G11C13/04; G11C13/042; G11C13/045
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
55 words
A method for improving holographic storage which comprises: recording an interferogram of a reference wave and an object wave on the ionic crystal with a random distribution of anisotropic centers: beaming only said reference wave in the erase mode on the crystal; and beaming only said object wave in the erase mode on the crystal.
Claim 2
Independent Claim
55 words
A method for improving holographic storage which comprises: recording an interferogram of a reference wave and an object wave on the ionic crystal with a random distribution of anisotropic centers: beaming only said reference wave in the erase mode on the crystal; and beaming only said object wave in the erase mode on the crystal.
Claim 3
Dependent Claim
33 words
The method of claim 1 wherein said ionic crystal is an alkali halide crystal and said anisotropic centers are selected from the class consisting of F A , M, and M A centers.
Claim 4
Dependent Claim
23 words
The method of claim 2 wherein said ionic crystal is selected from the class consisting of potassium chloride, sodium fluoride, and potassium fluoride.
Claim 5
Dependent Claim
16 words
The method of claim 3 wherein said ionic crystal has a thickness greater than 10λ/sin θ.
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) | 1980-07-25 | 1981-01-24 | 1981-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-25 | 1985-01-24 | 1985-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-25 | 1989-01-24 | 1989-07-26 | $7700.00 | Window Closed / Lapsed |