US4101976A
Expired / Lapsed
US
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Frequency selective optical data storage system
Assignee: International Business Machines Corp
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Filing: 1977-02-14
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Granted: 1978-07-18
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Expires: 1997-02-14
Abstract
Abstract An optical data storage system and method that utilizes the frequency dimension to increase the storage capacity significantly. The system includes a storage material, for example, in the form of a block, adapted to undergo a photo induced reaction upon exposure to light and which exhibits inhomogeneous absorption line broadening. Data bits are stored by selective photo induced reactions induced by a narrow band laser at specific frequencies within the broad inhomogeneous line. The lifetime of these photo induced data bits is of the order of years so as to provide a non-volatile storage system. In a preferred embodiment, a material is selected so that the photo induced reaction can be made reversible thereby permitting, when desired, the erasing of the data bits.
Inventors
- 👤 George Castro
- 👤 Dietrich Haarer
- 👤 Roger Morton MacFarlane
- 👤 Hans Peter Trommsdorff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:54
CPC Classifications
G; G11; G11C; G11C13/00; G11C13/04; G11C13/041
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
90 words
A frequency selective optical data storage system comprising: a material, said material exhibiting inhomogeneous absorption line broadening and capable of storing at least two data bits in the frequency dimension, said material adapted to undergo a photo-induced reaction resulting in information stored in the non-volatile ground state of the material upon exposure to a light source having a wavelength bandwidth narrower than the inhomogeneous line width, and a first laser adapted to write non-volatile information on said material with a wavelength narrower than and within the broad inhomogeneous absorption line.
Claim 2
Dependent Claim
90 words
A frequency selective optical data storage system comprising: a material, said material exhibiting inhomogeneous absorption line broadening and capable of storing at least two data bits in the frequency dimension, said material adapted to undergo a photo-induced reaction resulting in information stored in the non-volatile ground state of the material upon exposure to a light source having a wavelength bandwidth narrower than the inhomogeneous line width, and a first laser adapted to write non-volatile information on said material with a wavelength narrower than and within the broad inhomogeneous absorption line.
Claim 3
Dependent Claim
15 words
A system as described in claim 1 wherein said material undergoes a reversible photoinduced reaction.
Claim 4
Dependent Claim
15 words
A system as described in claim 1 wherein said material undergoes an irreversible photoinduced reaction.
Claim 5
Dependent Claim
14 words
A system as described in claim 1 wherein said material undergoes a photochemical reaction.
Claim 6
Dependent Claim
14 words
A system as described in claim 1 wherein said material undergoes a photochromic reaction.
Claim 7
Dependent Claim
17 words
A system as described in claim 1 wherein said first laser is adapted to read said information.
Claim 8
Dependent Claim
16 words
A system as described in claim 1 wherein said laser is adapted to scan said material.
Claim 9
Dependent Claim
16 words
A system as described in claim 1 including a second laser adapted to read said information.
Claim 10
Dependent Claim
105 words
A three-dimensional optical data storage system comprising: a layer of material having an inhomogeneous absorption line broadening and capable of storing at least two data bits in the frequency dimension, said material adapted to undergo a photo-induced reaction upon exposure to a light source having a wavelength bandwidth narrower than the inhomogeneous line width whereby said material is converted to a new structural configuration in the ground state, and a first laser adapted to form a hole in a narrow band mode with a wavelength narrower than and in said inhomogeneous absorption line wherein non-volatile information is formed in the frequency dimension of said system.
Claim 11
Dependent Claim
105 words
A three-dimensional optical data storage system comprising: a layer of material having an inhomogeneous absorption line broadening and capable of storing at least two data bits in the frequency dimension, said material adapted to undergo a photo-induced reaction upon exposure to a light source having a wavelength bandwidth narrower than the inhomogeneous line width whereby said material is converted to a new structural configuration in the ground state, and a first laser adapted to form a hole in a narrow band mode with a wavelength narrower than and in said inhomogeneous absorption line wherein non-volatile information is formed in the frequency dimension of said system.
Claim 12
Dependent Claim
108 words
A four-dimensional holographic memory system comprising: a block of material having an inhomogeneous absorption line broadening and capable of storing at least two data bits in the frequency dimension, said material adapted to undergo a photo-induced reaction upon exposure to a light source having a wavelength bandwidth narrower than the inhomogeneous line width whereby said material is converted to a new structural configuration in the non-volatile ground state, and a first laser adapted to form a hole in a narrow band mode with a wavelength narrower than and in said inhomogeneous absorption line of said block wherein non-volatile information is formed in the frequency dimension of said system.
Claim 13
Dependent Claim
108 words
A four-dimensional holographic memory system comprising: a block of material having an inhomogeneous absorption line broadening and capable of storing at least two data bits in the frequency dimension, said material adapted to undergo a photo-induced reaction upon exposure to a light source having a wavelength bandwidth narrower than the inhomogeneous line width whereby said material is converted to a new structural configuration in the non-volatile ground state, and a first laser adapted to form a hole in a narrow band mode with a wavelength narrower than and in said inhomogeneous absorption line of said block wherein non-volatile information is formed in the frequency dimension of said system.
Claim 14
Independent Claim
126 words
A method of storing data in an optical storage system comprising the steps of: providing a material exhibiting inhomogeneous absorption line broadening and capable of storing at least two data bits in the frequency dimension, said material adapted to undergo a photo-induced reaction resulting in information stored in the non-volatile ground state of the material upon exposure to a light source having a wavelength bandwidth narrower than the inhomogeneous line width, and exposing said material to light at a specific frequency with a wavelength narrower than and within the inhomogeneous line width whereby a reaction occurs in said material to form a hole in the frequency dimension which represents a data bit, said material adapted so that said hole remains upon the removal of said light.
Claim 15
Independent Claim
126 words
A method of storing data in an optical storage system comprising the steps of: providing a material exhibiting inhomogeneous absorption line broadening and capable of storing at least two data bits in the frequency dimension, said material adapted to undergo a photo-induced reaction resulting in information stored in the non-volatile ground state of the material upon exposure to a light source having a wavelength bandwidth narrower than the inhomogeneous line width, and exposing said material to light at a specific frequency with a wavelength narrower than and within the inhomogeneous line width whereby a reaction occurs in said material to form a hole in the frequency dimension which represents a data bit, said material adapted so that said hole remains upon the removal of said light.
Claim 16
Dependent Claim
18 words
A method as described in claim 11 whereby a laser is used to expose said material to light.
Claim 17
Dependent Claim
34 words
A method as described in claim 12 whereby said laser scans the broad inhomogeneous line to expose said material to light at a plurality of specific frequencies to form a plurality of data bits.
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) | 1981-07-17 | 1982-01-16 | 1982-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-17 | 1986-01-16 | 1986-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-17 | 1990-01-16 | 1990-07-18 | $7700.00 | Window Closed / Lapsed |