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US5138489A
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Spatially incoherent holographic correlator
Assignee: Leland Stanford Junior University
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Filing: 1991-06-10
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Granted: 1992-08-11
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Expires: 2011-06-10
Abstract
Abstract An incoherent holographic correlator comprising a two-dimensional array of surface-emitting lasers which are selectable in an arbitrary pattern so as to emit a beam containing the pattern. The pattern is spatially incoherent because the lasers are not phase-locked but it is temporally coherent. The beams are collimated onto a recorded hologram, and each of the beams produces a diffracted beam from the recording. All the diffracted beams are focused onto an imaging plane. A high-intensity spot represents a strong correlation between the selected pattern on the laser array and the image previously recorded in the hologram.
Inventors
- 👤 Eung-Gi Paek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:49
CPC Classifications
G; G06; G06E; G06E3/00; G06E3/001; G06E3/003; G06V; G06V10/00; G06V10/88; G06V10/89; G06V10/893; G06V10/895
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
81 words
An incoherent holographic correlator, comprising: an array of individually activatable surface-emitting diode lasers, said diode lasers being optically non-coherent among themselves when more than one of said diode lasers are activated; means for simultaneously activating a selected plurality of said diode lasers to form an emitting pattern; a hologram impressed with at least one reference pattern and irradiated with said emitting pattern; and a surface upon which images reconstructed through said hologram by all of said activated diodes lasers are overlapped.
Claim 2
Dependent Claim
81 words
An incoherent holographic correlator, comprising: an array of individually activatable surface-emitting diode lasers, said diode lasers being optically non-coherent among themselves when more than one of said diode lasers are activated; means for simultaneously activating a selected plurality of said diode lasers to form an emitting pattern; a hologram impressed with at least one reference pattern and irradiated with said emitting pattern; and a surface upon which images reconstructed through said hologram by all of said activated diodes lasers are overlapped.
Claim 3
Dependent Claim
20 words
An incoherent correlator as recited in claim 1, wherein said array of lasers are integrated in an optical integrated circuit.
Claim 4
Dependent Claim
25 words
An incoherent correlator as recited in claim 2, wherein said array of lasers are arranged in a two dimensional array on said optical integrated circuit.
Claim 5
Dependent Claim
27 words
An incoherent holographic correlator as recited in claim 2, further comprising a first optical system for collimating beams emanating from said activated diode lasers onto said hologram.
Claim 6
Dependent Claim
25 words
An incoherent correlator as recited in claim 4, further comprising a second optical system for focusing a beam diffracted from said hologram onto said surface.
Claim 7
Dependent Claim
19 words
An incoherent holographic correlator as recited in claim 4, further comprising at least one photodetector disposed at said surface.
Claim 8
Dependent Claim
24 words
An incoherent holographic correlator as recited in claim 6, where said at least one photodetector is an array of photodetectors arranged on said surface.
Claim 9
Dependent Claim
19 words
An incoherent holographic correlator as recited in claim 7, further comprising threshold circuits associated with each of said photodetectors.
Claim 10
Dependent Claim
36 words
An incoherent holographic correlator as recited in claim 7, further comprising an array of second surface-emitting diode lasers separately activatable in response to an output of a respective one of said photodetectors exceeding a predetermined threshold.
Claim 11
Dependent Claim
18 words
An incoherent correlator as recited in claim 9, wherein output beams of said second lasers irradiate said hologram.
Claim 12
Dependent Claim
34 words
An incoherent correlator as recited in claim 4, wherein said hologram is a reflective hologram and further comprising: a beam splitter interposed between said laser array, said hologram, and said at least one photodetector.
Claim 13
Dependent Claim
26 words
An incoherent correlator as recited in claim 4, wherein said array of lasers, said first optical system, and said hologram as integrated into a rigid structure.
Claim 14
Dependent Claim
94 words
An integrated incoherent holographic correlator, comprising: a spacer substantially transparent at a wavelength; an array of surface-emitting lasers emitting at said wavelength and formed on a first side of said spacer; at least one photodetector responsive to said wavelength and formed on said first side of said spacer; a lens having a focal length, formed on a second side of said spacer and separated from said array of surface-emitting lasers by an optical distance equal to said focal length; and a hologram integratedly attached to a side of said lens opposite from said spacer.
Claim 15
Dependent Claim
94 words
An integrated incoherent holographic correlator, comprising: a spacer substantially transparent at a wavelength; an array of surface-emitting lasers emitting at said wavelength and formed on a first side of said spacer; at least one photodetector responsive to said wavelength and formed on said first side of said spacer; a lens having a focal length, formed on a second side of said spacer and separated from said array of surface-emitting lasers by an optical distance equal to said focal length; and a hologram integratedly attached to a side of said lens opposite from said spacer.
Claim 16
Dependent Claim
34 words
An integrated incoherent holographic correlator as recited in claim 13, further comprising a body in which a diffraction pattern of said hologram is impressed on a side of said body opposite from said lens.
References Cited (Backward Citations)
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