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US3572934A
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Longitudinally reversed shearing interferometry
Assignee: International Business Machines Corp
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Filing: 1968-09-09
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Granted: 1971-03-30
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Expires: 1988-09-09
Abstract
Abstract A type of shearing interferometry is presented in which an interferogram is formed by the object wavefront and its replica folded in the longitudinal direction. An off-axis hologram of the object is first made in a conventional manner. The hologram is then illuminated to form a real and a virtual image. The real and the virtual images are superimposed. The result is a longitudinally reversed shear interferogram which indicates twice the phase variation of the object.
Inventors
- 👤 Olof Bryngdahl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:40
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/41; G01N21/45; G01N21/453; G01B; G01B9/00; G01B9/02; G01B9/021; Y; Y10; Y10S; Y10S359/00; Y10S359/90; Y10S359/902
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
62 words
The method of generating longitudinally reversed shear interferogram comprising: generating a hologram of an object using two light beams separated by an angle s; simultaneously illuminating said hologram with two light beams separated by an angle 2s; interacting the coincident real and virtual images so generated to produce an interferogram the fringe pattern in which represents twice the phase of said object.
Claim 2
Independent Claim
62 words
The method of generating longitudinally reversed shear interferogram comprising: generating a hologram of an object using two light beams separated by an angle s; simultaneously illuminating said hologram with two light beams separated by an angle 2s; interacting the coincident real and virtual images so generated to produce an interferogram the fringe pattern in which represents twice the phase of said object.
Claim 3
Independent Claim
68 words
The method of generating a longitudinally reversed shear interferogram comprising: generating a hologram from said object; generating in substantially the same plane and along the same optical axis a real and a virtual image from said hologram, said real image being orthoscopic and said virtual image being pseudoscopic; and interacting said images to produce an interferogram indicative of differences between said orthoscopic and pseudoscopic images of said object.
Claim 4
Independent Claim
68 words
The method of generating a longitudinally reversed shear interferogram comprising: generating a hologram from said object; generating in substantially the same plane and along the same optical axis a real and a virtual image from said hologram, said real image being orthoscopic and said virtual image being pseudoscopic; and interacting said images to produce an interferogram indicative of differences between said orthoscopic and pseudoscopic images of said object.
Claim 5
Dependent Claim
25 words
The method recited in claim 2, wherein the step generating said real and virtual images is by illuminating said hologram with a single light beam.
Claim 6
Dependent Claim
47 words
The method recited in claim 2, wherein the step of generating said real and virtual images is by illuminating said holograms with a single beam, and including the step of rotating said images relative to each other to orient both of said images in the same direction.
Claim 7
Dependent Claim
46 words
The method recited in claim 2, wherein the generating of said hologram is by using two beams separated by an angle s, and the step of generating said images is by directing two reference beams at said hologram, said beams being separated by an angle 2s.
Claim 8
Dependent Claim
50 words
The method recited in claim 1, wherein said two beams used in generating said hologram are generated by passing light through said object and through a diffraction grating producing a diffraction pattern having a plurality of orders, the light in two different diffraction orders being interacted to form said hologram.
Claim 9
Dependent Claim
65 words
The method recited in claim 6, wherein said two beams for illuminating said hologram are generated by passing light through a diffraction grating generating a diffraction pattern having a plurality of diffraction orders, choosing two of said orders for illuminating said hologram, the diffraction orders selected for illuminating said hologram being separated by twice the angle of the diffraction orders used in generating said hologram.
Claim 10
Dependent Claim
94 words
The method recited in claim 2, wherein the fringe pattern in said interferogram is made to represent more than twice the phase of said object by the steps of: making a second hologram from said hologram generated from said object by generating from said hologram a diffraction pattern having a plurality of diffraction orders; and interacting two of said diffraction orders to generate said second hologram, and generating said interferogram by illuminating said second hologram with two light beams separated by twice the angle of the light beams used in generating said second 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) | 1974-03-29 | 1974-09-28 | 1975-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-29 | 1978-09-28 | 1979-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-29 | 1982-09-28 | 1983-03-30 | $7700.00 | Window Closed / Lapsed |