US3794426A
Expired / Lapsed
US
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Holographic spectrometer
Assignee: Bendix Corp
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Filing: 1972-12-08
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Granted: 1974-02-26
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Expires: 1992-12-08
Abstract
Abstract A spectrometer employing the principles of single point holograms, that is, Fresnel zone plate patterns (FZP), is described. The holographic recording medium and the pinhole required for making an FZP are permanently arranged on opposite sides of a transparent support medium. The interference pattern is then recorded by illuminating the recording medium with monochromatic light of a selected wavelength. Spectral analysis of light which is not monochromatic can later be made by illuminating the recorded interference pattern and by varying the optical path length between the interference pattern and a second pinhole positioned in front of a detector. Changes in the optical path between the second pinhole and the interference pattern correspond to changes in the wavelength of light which is focused on the permanently positioned pinhole. Different wavelengths can thus be detected by varying the optical path length between the second pinhole and the interference pattern and noting the intensity which passes through the fixed pinhole. The permanent mounting relationship of the illuminated pinhole and the interference pattern eliminates the usual difficulty of aligning these two components to some small fraction of a wavelength, and any aberrations produced by the structure or recording medium are cancelled during the illumination of the pattern.
Inventors
- 👤 R Mueller
- 👤 A Lohmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:34
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/32
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
164 words
A spectrometer for identifying the wavelengths of electromagnetic energy emanating from a source comprising: energy transparent support means having two parallel plane faces in a predetermined spaced relationship and an optical axis passing through both of said parallel faces; an opaque material disposed over one of said parallel faces, said opaque material having a radiation aperture aligned with said optical axis; a permanent interference pattern indicative of said radiation aperture disposed on the other of said two parallel plane faces for forming serially disposed images of said source along said optical axis wherein each of said images is indicative of a particular wavelength of energy emanating from said source; energy detector means disposed along said optical axis for detecting energy from said source after passing through said interference pattern; means for varying the position of said images along said oPtical axis so that each image can be individually detected by said energy detector and the different wavelengths of energy indicative of each image determined.
Claim 2
Dependent Claim
164 words
A spectrometer for identifying the wavelengths of electromagnetic energy emanating from a source comprising: energy transparent support means having two parallel plane faces in a predetermined spaced relationship and an optical axis passing through both of said parallel faces; an opaque material disposed over one of said parallel faces, said opaque material having a radiation aperture aligned with said optical axis; a permanent interference pattern indicative of said radiation aperture disposed on the other of said two parallel plane faces for forming serially disposed images of said source along said optical axis wherein each of said images is indicative of a particular wavelength of energy emanating from said source; energy detector means disposed along said optical axis for detecting energy from said source after passing through said interference pattern; means for varying the position of said images along said oPtical axis so that each image can be individually detected by said energy detector and the different wavelengths of energy indicative of each image determined.
Claim 3
Dependent Claim
69 words
The spectrometer of claim 1 wherein said interference pattern faces said source and said detector is located behind said radiation aperture, said spectrometer further includes an entrance pinhole aligned with said optical axis interposed between said source and said interference pattern so that individual wavelengths of light are identified by varying the position of the images of the pinhole to individually focus on said detector through said radiation aperture.
Claim 4
Dependent Claim
32 words
The spectrometer of claim 2 wherein said support means is a solid element said means for varying is a means for optically varying the distance between said pinhole and said interference pattern.
Claim 5
Dependent Claim
82 words
The spectrometer of claim 1 further including a two-sided optical member serially disposed with respect to said support means along said optical axis, said optical member having an exit pinhole on one of said sides and the other of said sides, being adjacent to said interference pattern wherein: said energy detector is located behind said exit pinhole; and said means for varying includes means for varying the index of refraction of at least one of said optical member and said support means.
Claim 6
Dependent Claim
52 words
The spectrometer of claim 4 wherein said support means is a hollow member having means for inserting and removing fluid to thereby change the index of refraction of said support means, said means for varying is a means for inserting and removing from said support means fluids having different index'' of refraction.
Claim 7
Dependent Claim
13 words
The spectrometer of claim 5 wherein said optical member is a solid member.
Claim 8
Dependent Claim
52 words
The spectrometer of claim 5 wherein said optical member is a hollow member having means for inserting and removing fluid to thereby change the index of refraction of said optical member, said means for varying is a means for inserting and removing from said optical member fluids having different index'' of refraction.
Claim 9
Dependent Claim
47 words
The spectrometer of claim 1 wherein said radiation aperture faces said source said means for varying includes a pinhole slidably supported between said interference pattern and said detector so that individual wavelengths of light are identified by changing the spacing between said interference pattern and said pinhole.
Claim 10
Dependent Claim
16 words
The spectrometer of claim 8 wherein said detector is arranged to slide along with said pinhole.
References Cited (Backward Citations)
US2463280A
Cited
US3680943A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |