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US3924952A
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Arrangement and method for studying radiation by interferential spectrometry
Assignee: Bpifrance Financement SA
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Filing: 1974-02-06
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Granted: 1975-12-09
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Expires: 1994-02-06
Abstract
Abstract An arrangement and a method for studying radiation by interferential spectrometry. The arrangement includes, starting from a light source, an interferometer-splitter for dividing the source into two beams the interferometer being preferably a Sagnac interferometer, a lens objective, a displaceable grating and means for observing and processing the resultant flux, and at least one reference screen and one grating juxtaposed in the focal plane of the lens, and in which the difference between the out-going fluxes is measured. Preferably at least one reference screen and one grating are juxtaposed in the focal plane of the lens. Signals are received, transformed into current, from each grating. The difference between the two currents is determined for obtaining a result proportional to the integral of correlation integral i ( Delta ) iR ( Delta ) d Delta . This system is particularly useful in the study of radiation having a very rapid temporal evolution.
Inventors
- 👤 Robert Gaston Andre Marechal
- 👤 Gerard Fortunato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:08
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/45; G01J3/453
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
119 words
An arrangement for studying the spectrum of a source, which comprises: interferometer means for receiving light from said source and splitting it into two laterally spaced images having substantially equal intensities; lens means for focusing light from said two images to provide a luminous interference pattern in the back focal plane of said lens means, which pattern is an exact, high contrast Fourier transform of the spectrum of said source obtained for positive and negative values of the optical path difference existing by virtue of the lateral spacing of said images; and modifying means located at said back focal plane for operating on said Fourier transform to analyze said pattern and obtain information about the spectrum of said source.
Claim 2
Dependent Claim
119 words
An arrangement for studying the spectrum of a source, which comprises: interferometer means for receiving light from said source and splitting it into two laterally spaced images having substantially equal intensities; lens means for focusing light from said two images to provide a luminous interference pattern in the back focal plane of said lens means, which pattern is an exact, high contrast Fourier transform of the spectrum of said source obtained for positive and negative values of the optical path difference existing by virtue of the lateral spacing of said images; and modifying means located at said back focal plane for operating on said Fourier transform to analyze said pattern and obtain information about the spectrum of said source.
Claim 3
Dependent Claim
28 words
An arrangement as defined in claim 1 wherein said modifying means is an interferogram in the form of the Fourier transform of the spectrum of a reference source.
Claim 4
Dependent Claim
39 words
An arrangement as defined in claim 1 wherein said modifying means includes a mask havinG an energy transparency which varies according to the nth power of said optical path difference whereby to obtain the nth derivative of said spectrum.
Claim 5
Dependent Claim
58 words
An arrangement as defined in claim 2 wherein said modifying means also includes a mask having an energy transparency which varies according to the (n + p)th power of said optical path difference whereby to obtain comparison between the nth derivative of the spectrum of said source with the pth derivative of the spectrum of said reference source.
Claim 6
Dependent Claim
61 words
An arrangement as defined in claim 1 wherein said modifying means includes a pair of complementary gratings, one positive and one negative, juxtaposed in said back focal plane, and a pair of receiver means, one for each complementary grating, for receiving signals respectively from said positive and said negative complementary gratings whereby information about the spectrum of said source is obtained.
Claim 7
Dependent Claim
34 words
An arrangement as defined in claim 5 for use in studying the spectrum of radiation having a rapid temporal evolution, said modifying means including a periodic grating showing the interferogram of a monochromatic source.
Claim 8
Dependent Claim
54 words
An arrangement as defined in claim 2 for use when the temporal evolution of the radiation being studied is not very rapid wherein said modifying means includes a single grating showing the interferogram of a monochromatic source, and means for effecting relative movement between single grating and the fringes of said luminous interference pattern.
Claim 9
Dependent Claim
13 words
System according to claim 1, wherein the interferometer means is a Sagnac interferometer.
Claim 10
Independent Claim
71 words
The method of analyzing the spectrum of a source which comprises the steps of: a. forming laterally spaced point-by-point coherent images of a source, said images having substantially equal intensities; b. focusing light coming from said images in a selected plane to produce an interference pattern which is the Fourier transform of the spectrum of said source; and c. operating on said Fourier transform to analyze the spectrum of said source.
Claim 11
Independent Claim
71 words
The method of analyzing the spectrum of a source which comprises the steps of: a. forming laterally spaced point-by-point coherent images of a source, said images having substantially equal intensities; b. focusing light coming from said images in a selected plane to produce an interference pattern which is the Fourier transform of the spectrum of said source; and c. operating on said Fourier transform to analyze the spectrum of said source.
Claim 12
Dependent Claim
31 words
The method according to claim 9 wherein the operation of step (c) is multiplication of said Fourier transform by the nth power of the path difference which produces the interference pattern.
Claim 13
Dependent Claim
33 words
The method according to claim 9 wherein the operation of step (c) is correlation of a derivative of the spectrum of said source with a derivative of the spectrum of a reference source.
Claim 14
Dependent Claim
50 words
The method according to claim 9 for use when the temporal evolution of the spectrum is not very rapid, wherein the operation of step (c) includes: providing, in said selected plane, two complementary gratings, one positive and one negative; and alterately occulting said two complementary gratings at a predetermined frequency.
Claim 15
Dependent Claim
53 words
The method according to claim 9 for when the temporal evolution of the spectrum is not very rapid, wherein the operation of step (c) includes: providing, in said selected plane, a single grating; and displacing said single grating a distance equal to a fraction of the average interfringe spacing of said interference pattern.
Claim 16
Dependent Claim
54 words
The method according to claim 9 for use when the temporal evolution of the spectrum is not very rapid, wherein the operation of step (c) includes: providing, in said selected plane, a single grating; and displacing said single grating a distance equal to a multiple of the average interfringe spacing of said interference pattern.
Claim 17
Dependent Claim
29 words
The method according to claim 9 wherein the operation of step (c) is correlation of said Fourier transform with the Fourier transform of the spectrum of a reference source.
References Cited (Backward Citations)
US3836254A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |