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US3700334A Expired / Lapsed US ⏱️ 0.0 years remaining

Interferometer-polarimeter

Assignee: National Aeronautics and Space Administration
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Filing: 1970-11-13
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Granted: 1972-10-24
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Expires: 1990-11-13
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Abstract

Abstract A system for measuring the intensity and state of polarization of a radiation field as well as obtaining the spectral variations of these quantities with a wide range of spectral resolution, i.e., from low to extremely high resolution values, is disclosed. The system generally includes any standard or conventional twobeam interferometer which is modified by the inclusion of a polarizer in each of the beams and an analyzer positioned in front of a sensor or recording device. More specifically, the system employs a beam splitter which serves to divide light from a selected light source into a pair of individual light beams. Each of the light beams is directed through a polarizer. The polarizers are positioned to have preselected planes of polarization with respect to each other and with respect to the plane of polarization of the analyzer. The polarized light beams are applied to a variable optical retarder which serves to selectively modify the relative optical path lengths of the light beams. An optical mixer may be employed to recombine the two light beams. The recombined light beams are projected through an analyzer, such as a linear polarizer, to a sensor or recording device.

Inventors

  • 👤 Alain L Fymat
  • 👤 Krishna D Abhyankar

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 20:47
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/45; G01J3/453; G01J3/4537; G01N; G01N21/00; G01N21/17; G01N21/21

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 153 words
Apparatus for producing interferograms from which the four Stokes parameters defining both intensity and the state of polarization of incident radiation, and special variations thereof, can be concurrently determined, said apparatus comprising: a two-beam interferometer including: splitter means for dividing incident radiation into two beams, retarder means for controllably producing phase differences between said two beams, and recombiner means for combining said two beams into a single recombined beam of radiation; first and second polarizers, each positioned in a respective one of said two beams and interposed between said splitter means and said retarder means, said first and second polarizers being adapted to have the polarization angles thereof selectively modified; and a third polarizer positioned in said recombined beam of radiation, said first, second and third polarizers being successively positioned to form preselected combinations of polarization angles, an interferogram being obtained for each successive combination to permit concurrent determination of said Stokes parameters.
Claim 2
Dependent Claim 153 words
Apparatus for producing interferograms from which the four Stokes parameters defining both intensity and the state of polarization of incident radiation, and special variations thereof, can be concurrently determined, said apparatus comprising: a two-beam interferometer including: splitter means for dividing incident radiation into two beams, retarder means for controllably producing phase differences between said two beams, and recombiner means for combining said two beams into a single recombined beam of radiation; first and second polarizers, each positioned in a respective one of said two beams and interposed between said splitter means and said retarder means, said first and second polarizers being adapted to have the polarization angles thereof selectively modified; and a third polarizer positioned in said recombined beam of radiation, said first, second and third polarizers being successively positioned to form preselected combinations of polarization angles, an interferogram being obtained for each successive combination to permit concurrent determination of said Stokes parameters.
Claim 3
Dependent Claim 31 words
The apparatus defined by claim 1 wherein said first, second and third polarizers are linear polarizers, said polarizers being adapted to be adjusted to polarize at any angle light projected therethrough.
Claim 4
Dependent Claim 38 words
The apparatus defined by claim 1 wherein said first and second polarizers are circular polarizers and said third polarizer Is a linear polarizer, said first and second polarizer together forming selected combinations of right and left circular polarizers.
Claim 5
Dependent Claim 13 words
The apparatus defined by claim 1 wherein said interferometer is a Michelson interferometer.
Claim 6
Dependent Claim 65 words
The apparatus defined by claim 1 wherein said retarder means comprises first and second mirrors positioned in a respective one of said two beams for reflecting incident radiation, one of said first and second mirrors being stationary and the other of said mirrors being adapted to be moved controllably along the path of incident radiation, the relative phase of said two beams being thereby controlled.
Claim 7
Dependent Claim 37 words
The apparatus defined by claim 5 wherein said first, second and third polarizers are linear polarizers, said polarizers being adapted to be adjusted to polarize at any angle light projected therethrough, said interferometer being a Michelson interferometer.
Claim 8
Dependent Claim 47 words
The apparatus defined by Claim 5 wherein said first and second polarizers are circular polarizers and said third polarizer is a linear polarizer, said first and second polarizers being changeable to together form selected combinations of right and left circular polarizers, said interferometer being a Michelson interferometer.

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) 1975-10-24 1976-04-24 1976-10-24 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-10-24 1980-04-24 1980-10-24 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-10-24 1984-04-24 1984-10-24 $7700.00 Window Closed / Lapsed

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