US3639031A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hologram copying for reconstruction of an aberration-free wavefront at a wavelength differing from the copying wavelength
Assignee: AT&T Inc
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Filing: 1970-09-24
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Granted: 1972-02-01
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Expires: 1990-09-24
Abstract
Abstract A first thick hologram of the wave front from an object is formed at a first wavelength to which a first hologram-recording medium is sensitive. A second hologram is recorded on a second recording medium sensitive to a second wavelength by placing the second recording medium adjacent the first and illuminating the first hologram with radiation at the second wavelength. This second hologram can then be illuminated with radiation of the first wavelength to reconstruct with minimum aberration the wave front associated with the object recorded on the first hologram.
Inventors
- 👤 Lawrence H Lin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:18
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/04; G03H1/20; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
251 words
A method for forming a hologram comprising the steps of: forming a first thick hologram by interfering on a first thick hologram recording medium an information-bearing beam and a reference beam of electromagnetic radiation that is coherent with the information-bearing beam and has a first wavelength and a first angle of incidence on the recording medium; illuminating the first hologram with a first illuminating beam of electromagnetic radiation having a second wavelength and a second angle of incidence on the first hologram such that the ratio of the wavelength of the reference beam to the wavelength of the illuminating beam is approximately equal to the ratio of the sine of the first angle to the sine of the second angle; forming on a second recording medium a second hologram of a diffracted portion of the first illuminating beam and a coherent reference beam that is incident on the second recording medium at the same angle as the first illuminating beam is incident on the first hologram; and illuminating the second hologram with a second illuminating beam at approximately the same first wavelength and first angle of incidence to reconstruct the information-bearing beam in the first order with a minimum of the aberrations that would otherwise be found in a wave front reconstructed from a hologram that is illuminated with a beam of radiation that is different in wavelength and angle of incidence on the hologram from the wavelength and angle of incidence of a reference beam used in forming the hologram.
Claim 2
Independent Claim
251 words
A method for forming a hologram comprising the steps of: forming a first thick hologram by interfering on a first thick hologram recording medium an information-bearing beam and a reference beam of electromagnetic radiation that is coherent with the information-bearing beam and has a first wavelength and a first angle of incidence on the recording medium; illuminating the first hologram with a first illuminating beam of electromagnetic radiation having a second wavelength and a second angle of incidence on the first hologram such that the ratio of the wavelength of the reference beam to the wavelength of the illuminating beam is approximately equal to the ratio of the sine of the first angle to the sine of the second angle; forming on a second recording medium a second hologram of a diffracted portion of the first illuminating beam and a coherent reference beam that is incident on the second recording medium at the same angle as the first illuminating beam is incident on the first hologram; and illuminating the second hologram with a second illuminating beam at approximately the same first wavelength and first angle of incidence to reconstruct the information-bearing beam in the first order with a minimum of the aberrations that would otherwise be found in a wave front reconstructed from a hologram that is illuminated with a beam of radiation that is different in wavelength and angle of incidence on the hologram from the wavelength and angle of incidence of a reference beam used in forming the hologram.
Claim 3
Dependent Claim
42 words
The method of claim 1 wherein the first recording medium is sensitive to radiation having a wavelength longer than 5,500 A., the second recording medium is sensitive to radiation shorter than 5,500 A. and the second wavelength is shorter than 5,500 A.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein the second recording medium is sufficiently thick that the second hologram is a thick hologram.
Claim 5
Dependent Claim
13 words
The method of claim 3 wherein the second recording medium is dichromated gelatin.
Claim 6
Dependent Claim
41 words
The method of claim 1 wherein the second recording medium is located immediately adjacent the first hologram and parallel to it and the second hologram is formed from the diffracted and undiffracted portions of the beam that illuminates the first hologram.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-31 | 1975-08-02 | 1976-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-31 | 1979-08-02 | 1980-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-31 | 1983-08-02 | 1984-02-01 | $7700.00 | Window Closed / Lapsed |