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US3799642A
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Holographic recording on photochromic lithium niobate
Assignee: RCA Corp
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Filing: 1973-03-27
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Granted: 1974-03-26
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Expires: 1993-03-27
Abstract
Abstract Photochromic lithium niobate crystals containing iron and either manganese or copper are useful for recording phase holograms in the photosensitive state of the crystals, which holograms can be permanently fixed and read out without loss in the quality of the image obtained therefrom over extended periods.
Inventors
- 👤 W Phillips
- 👤 D Staebler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:11
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/02; G03C; G03C1/00; G03C1/72; G03C1/725; G03H2001/026; G03H2001/0268; G03H2260/00; G03H2260/50; G03H2260/52; G03H2260/54; Y; Y10; Y10S; Y10S359/00; Y10S359/90; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
113 words
A method for producing one or more light stable phase holograms in an electro-optic crystal which comprises exposing a photochromic lithium niobate crystal containing at least about 0.001 mol percent of iron as a first dopant and at least about 0.001 mol percent of a second dopant selected from the group consisting of manganese and copper to ultraviolet light, recording a hologram in the crystal in the form of a spatial pattern with a modulated coherent object beam and a coherent reference beam in the visible wavelength range, fixing the pattern so as to replace the original electronic charge pattern with an ionic charge pattern, and bleaching the crystal to its insensitive state.
Claim 2
Dependent Claim
18 words
A method according to claim 2 wherein the bleaching step comprises exposing the crystal to incoherent visible light.
Claim 3
Dependent Claim
33 words
A method according to claim 2 wherein the bleaching step comprises heating the crystal for a time long enough to photochromically switch it to its insensitive state but insufficient to erase the hologram.
Claim 4
Dependent Claim
107 words
In a system for recording phase holograms which comprises a laser, means for forming a modulated object beam and a reference beam in the visible wavelength range and an electro-optic crystal for recording the interference diffraction pattern formed by combining the object beam and the reference beam in the crystal, the improvement which comprises employing as the electro-optic crystal a photochromic lithium niobate crystal containing at least about 0.001 mol percent of iron as a first dopant and at least about 0.001 mol percent of a second dopant selected from the group consisting of manganese and copper, which crystal has been darkened by exposure to ultraviolet light.
Claim 5
Dependent Claim
12 words
The system according to claim 5 wherein the second dopant is manganese.
References Cited (Backward Citations)
US3703328A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |