US6351325B1
Expired / Lapsed
US
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Fiber-coupled, angled-dual-axis confocal scanning microscopes for imaging in a scattering medium
Assignee: Optical Biopsy Technologies Inc
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Filing: 2000-07-28
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Granted: 2002-02-26
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Expires: 2020-07-28
Abstract
Abstract This invention provides an angled-dual-axis confocal scanning microscope comprising a fiber-coupled, angled-dual-axis confocal head and a vertical scanning unit. The angled-dual-axis confocal head is configured such that an illumination beam and an observation beam intersect optimally at an angle θ within an object. The vertical scanning unit causes the angled-dual-axis confocal head to move towards or away from the object, thereby yielding a vertical scan that deepens into the object, while keeping the optical path lengths of the illumination and observation beams unchanged so to ensure the optimal intersection of the illumination and observation beams in the course of vertical scanning. The angled-dual-axis confocal scanning microscope may further comprises a transverse stage, causing the object to move relative to the angled-dual-axis confocal head along transverse directions perpendicular to the vertical direction, thereby producing a transverse scan. By assembling various transverse and/or vertical scans in a suitable manner, two-dimensional transverse and/or vertical cross-section images of the object can be obtained. A three-dimensional volume image of the object can be accordingly constructed. The angled-dual-axis confocal scanning microscope of the present invention provides a versatile and high resolution imaging tool, well suited for tissue and other biological imaging applications. Moreover, by employing relatively low numerical aperture focusing elements, fiber-optic components and a fiber-coupled laser, the present invention provides an assembly of fiber-based angled-dual-axis confocal systems that can be particularly powerful tools for performing low noise confocal scanning microscopy in a scattering medium.
Inventors
- 👤 Michael J. Mandella
- 👤 Mark H. Garrett
- 👤 Gordon S. Kino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:50
CPC Classifications
G; G02; G02B; G02B21/00; G02B21/0004; G02B21/002; G02B21/0024; G02B21/0052; G02B21/0056; G02B21/0068; G02B21/0072; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 91
Claim 1
Independent Claim
210 words
An angled-dual-axis confocal scanning system comprising: a) an angled-dual-axis confocal head comprising: i) a first optical fiber having first and second ends, for providing an illumination beam at said first end; ii) a second optical fiber having first and second ends; and iii) an angled-dual-axis focusing means for focusing said illumination beam to an illumination focal volume along an illumination axis within an object and for receiving an observation beam emanated from an observation focal volume along an observation axis within said object such that said observation beam is focused onto said first end of said second optical fiber; wherein said illumination axis and said observation axis intersect at an angle within said object, such that said illumination focal volume and said observation focal volume intersect optimally at a confocal overlapping volume; and b) a vertical scanning unit comprising: i) a vertical translation means mechanically coupled to said angled-dual-axis confocal head; and ii) a compensation means for ensuring said optimal intersection of said illumination focal volume and said observation focal volume; wherein said vertical translation means is capable of causing said angled-dual-axis confocal head to move relative to said object along a vertical direction, such that said confocal overlapping volume deepens progressively into said object, thereby producing a vertical scan.
Claim 2
Dependent Claim
210 words
An angled-dual-axis confocal scanning system comprising: a) an angled-dual-axis confocal head comprising: i) a first optical fiber having first and second ends, for providing an illumination beam at said first end; ii) a second optical fiber having first and second ends; and iii) an angled-dual-axis focusing means for focusing said illumination beam to an illumination focal volume along an illumination axis within an object and for receiving an observation beam emanated from an observation focal volume along an observation axis within said object such that said observation beam is focused onto said first end of said second optical fiber; wherein said illumination axis and said observation axis intersect at an angle within said object, such that said illumination focal volume and said observation focal volume intersect optimally at a confocal overlapping volume; and b) a vertical scanning unit comprising: i) a vertical translation means mechanically coupled to said angled-dual-axis confocal head; and ii) a compensation means for ensuring said optimal intersection of said illumination focal volume and said observation focal volume; wherein said vertical translation means is capable of causing said angled-dual-axis confocal head to move relative to said object along a vertical direction, such that said confocal overlapping volume deepens progressively into said object, thereby producing a vertical scan.
Claim 3
Dependent Claim
86 words
The angled-dual-axis confocal scanning system of claim 1 wherein said compensation means comprises a fluid filling a space between said angled-dual-axis focusing means and said object, wherein said fluid is substantially transparent to said illumination beam and said observation beam, and wherein said fluid has an index of refraction that is substantially the same as an index of refraction of said object, such that the optical path lengths of said illumination beam and said observation beam remain substantially unchanged in the course of said vertical scan.
Claim 4
Dependent Claim
30 words
The angled-dual-axis confocal scanning system of claim 2 further comprising a window assembly interposed between said angled-dual-axis focusing means and said fluid for passage of said illumination and observation beams.
Claim 5
Dependent Claim
18 words
The angled-dual-axis confocal scanning system of claim 3 wherein said window assembly comprises a substantially transparent flat window.
Claim 6
Dependent Claim
49 words
The angled-dual-axis confocal scanning system of claim 3 wherein said window assembly comprises first and second substantially transparent flat windows in an angled arrangement, such that said illumination axis is substantially perpendicular to said first flat window and said observation axis is substantially perpendicular to said second flat window.
Claim 7
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 2 further comprising a substantially transparent window interposed between said fluid and said object for passage of said illumination and observation beams.
Claim 8
Dependent Claim
34 words
The angled-dual-axis confocal scanning system of claim 2 wherein said fluid is contained in a sealed hydraulic system, including a reservoir for replenishing and receiving excess fluid in the course of said vertical scan.
Claim 9
Dependent Claim
60 words
The angled-dual-axis confocal scanning system of claim 1 further comprising a transverse stage mechanically coupled to said object, wherein said transverse stage causes said object to move relative to said angled-dual-axis confocal head along transverse directions perpendicular to said vertical direction, such that said confocal overlapping volume moves across said object along said transverse directions, thereby producing a transverse scan.
Claim 10
Dependent Claim
36 words
The angled-dual-axis confocal scanning system of claim 8 wherein said transverse stage comprises a substantially transparent window for passage of said illumination and observation beams, and wherein said window is in close contact with said object.
Claim 11
Dependent Claim
44 words
The angled-dual-axis confocal scanning system of claim 1 wherein said angled-dual-axis focusing means comprises one or more elements selected from the group consisting of refractive lenses, diffractive lenses, GRIN lenses, focusing gratings, micro-lenses, holographic optical elements, binary lenses, curved mirrors, flat mirrors, and prisms.
Claim 12
Dependent Claim
31 words
The angled-dual-axis confocal scanning system of claim 10 wherein said angled-dual-axis focusing means comprises a single illumination-observation focusing element, where said illumination-observation element provides said illumination axis and said observation axis.
Claim 13
Dependent Claim
44 words
The angled-dual-axis confocal scanning system of claim 11 further comprising a first collimating lens, wherein said first collimating lens receives said illumination beam from said first end of said first optical fiber and passes a substantially collimated illumination beam to said illumination-observation focusing element.
Claim 14
Dependent Claim
42 words
The angled-dual-axis confocal scanning system of claim 12 further comprising a second collimating lens, wherein said second collimating lens receives said observation beam from said illumination-observation focusing element and focuses said observation beam to said first end of said second optical fiber.
Claim 15
Dependent Claim
42 words
The angled-dual-axis confocal scanning system of claim 10 wherein said angled-dual-axis focusing means comprises an illumination focusing element and an observation focusing element, wherein said illumination focusing element provides said illumination axis, and wherein said observation focusing element provides said observation axis.
Claim 16
Dependent Claim
45 words
The angled-dual-axis confocal scanning system of claim 14 wherein said illumination focusing element and said observation focusing element are of the same type, comprising a focusing element selected from the group consisting of refractive lenses, diffractive lenses, GRIN lenses, micro-lenses, binary lenses, and curved mirrors.
Claim 17
Dependent Claim
24 words
The angled-dual-axis confocal scanning system of claim 15 wherein said focusing element has a numerical aperture (NA) in the range of 0.1 to 0.4.
Claim 18
Dependent Claim
44 words
The angled-dual-axis confocal scanning system of claim 14 further comprising a first collimating lens, wherein said first collimating lens receives said illumination beam from said first end of said first optical fiber and passes a substantially collimated illumination beam to said illumination focusing element.
Claim 19
Dependent Claim
42 words
The angled-dual-axis confocal scanning system of claim 17 further comprising a second collimating lens, wherein said second collimating lens receives said observation beam from said observation focusing element and focuses said observation beam to said first end of said second optical fiber.
Claim 20
Dependent Claim
73 words
The angled-dual-axis confocal scanning system of claim 14 further comprising one or more mirrors for beam-aligning and beam-deflecting, wherein said one or more mirrors receive said illumination beam from said illumination focusing element and direct said illumination beam to said illumination focal volume within said object, and wherein said one or more mirrors collect said observation beam emanated from said observation focal volume and pass said observation beam to said observation focusing element.
Claim 21
Dependent Claim
19 words
The angled-dual-axis confocal scanning system of claim 1 wherein said angled-dual-axis confocal head is mechanically coupled to a substrate.
Claim 22
Dependent Claim
18 words
The angled-dual-axis confocal scanning system of claim 20 wherein said substrate comprises a silicon substrate etched with V-grooves.
Claim 23
Dependent Claim
36 words
The angled-dual-axis confocal scanning system of claim 1 wherein either of said first and second optical fibers comprises an element selected from the group consisting of single-mode fibers, polarization maintaining fibers, multi-mode fibers, and birefrigent fibers.
Claim 24
Dependent Claim
21 words
The angled-dual-axis confocal scanning system of claim 22 wherein each of said first and second optical fibers comprises a single-mode fiber.
Claim 25
Dependent Claim
24 words
The angled-dual-axis confocal scanning system of claim 1 wherein said observation beam comprises reflected light emanated from said confocal overlapping volume within said object.
Claim 26
Dependent Claim
24 words
The angled-dual-axis confocal scanning system of claim 1 wherein said observation beam comprises fluorescent light emanated from said confocal overlapping volume within said object.
Claim 27
Dependent Claim
36 words
The angled-dual-axis confocal scanning system of claim 1 wherein said illumination focal volume and said observation focal volume are diffraction-limited, determined by main lobes of said illumination beam's point-spread function and said observation beam's point-spread function.
Claim 28
Dependent Claim
15 words
The angled-dual-axis confocal scanning system of claim 26 wherein said confocal overlapping volume is diffraction-limited.
Claim 29
Dependent Claim
27 words
The angled-dual-axis confocal scanning system of claim 1 wherein said illumination beam is a polarized beam, and wherein first and second optical fibers are polarization maintaining fibers.
Claim 30
Dependent Claim
24 words
The angled-dual-axis confocal scanning system of claim 1 further comprising a light source optically coupled to said second end of said first optical fiber.
Claim 31
Dependent Claim
36 words
The angled-dual-axis confocal scanning system of claim 29 wherein said light source comprises an element selected from the group consisting of optical fiber amplifiers, fiber lasers, semiconductor optical amplifiers, semiconductor lasers, and diode-pumped solid state lasers.
Claim 32
Dependent Claim
45 words
The angled-dual-axis scanning confocal system of claim 29 wherein said light source comprises a polarized light source, wherein said first and second optical fibers are polarization maintaining fibers, and wherein said second end of said second optical fiber is optically coupled to a polarizing beamsplitter.
Claim 33
Dependent Claim
19 words
The angled-dual-axis confocal scanning system of claim 31 further comprising two optical detectors, optically coupled to said polarizing beamsplitter.
Claim 34
Dependent Claim
26 words
The angled-dual-axis confocal scanning system of claim 1 further comprising one or more optical detectors optically coupled to said second end of said second optical fiber.
Claim 35
Dependent Claim
34 words
The angled-dual-axis confocal scanning system of claim 33 wherein said one or more optical detectors comprise one or more elements selected from the group consisting of PIN diodes, avalanche photo diodes, and photomultipler tubes.
Claim 36
Dependent Claim
62 words
The angled-dual-axis confocal scanning system of claim 1 further comprising a first optical circulator having first, second, and third ports, wherein said third port is optically coupled to said second end of said first optical fiber, wherein said first port is optically coupled to said second end of said second optical fiber, and wherein said second port provides a bi-directional input/output port.
Claim 37
Dependent Claim
50 words
The angled-dual-axis confocal scanning system of claim 35 further comprising a self-detecting laser source having first and second output apertures, wherein said first output aperture is optically coupled to said second port of said first optical circulator, and wherein said second output aperture is optically coupled to an optical detector.
Claim 38
Dependent Claim
31 words
The angled-dual-axis confocal scanning system of claim 36 wherein said self-detecting laser source comprises an element selected from the group consisting of fiber lasers, semiconductor lasers, and diode-pumped solid state lasers.
Claim 39
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 36 further comprising a frequency shifting means optically coupled to said second optical fiber, for shifting the frequency of said observation beam.
Claim 40
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 36 further comprising a frequency shifting means optically coupled to said first optical fiber, for shifting the frequency of said illumination beam.
Claim 41
Dependent Claim
35 words
The angled-dual-axis confocal scanning system of claim 36 further comprising a frequency shifting means in optical communication with said self-detecting light source and said first optical circulator, for shifting the frequency of said observation beam.
Claim 42
Dependent Claim
76 words
The angled-dual-axis confocal scanning system of claim 35 further comprising a self-detecting laser source having a single output aperture, wherein said output aperture is optically coupled to said second port of said first optical circulator via a beam-splitting means, such that said beam-splitting means routes a portion of an output beam emitted from said output aperture to said second port of said first optical circulator and a remainder of said output beam to an optical detector.
Claim 43
Dependent Claim
31 words
The angled-dual-axis confocal scanning system of claim 41 wherein said self-detecting light source comprises an element selected from the group consisting of fiber lasers, semiconductor lasers, and diode-pumped solid state lasers.
Claim 44
Dependent Claim
31 words
The angled-dual-axis confocal scanning system of claim 41 wherein said beam-splitting means comprises an element selected from the group consisting of fiber-optic couplers, polarization maintaining fiber-optic couplers, beamsplitters, and polarizing beamsplitters.
Claim 45
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 41 further comprising a frequency shifting means optically coupled to said second optical fiber, for shifting the frequency of said observation beam.
Claim 46
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 41 further comprising a frequency shifting means optically coupled to said first optical fiber, for shifting the frequency of said illumination beam.
Claim 47
Dependent Claim
34 words
The angled-dual-axis confocal scanning system of claim 41 further comprising a frequency shifting means in optical communication with said beam-splitting means and said first optical circulator, for shifting the frequency of said observation beam.
Claim 48
Dependent Claim
36 words
The angled-dual-axis confocal scanning system of claim 35 further comprising a second optical circulator having first, second and third ports, wherein said second port is optically coupled to said second port of said first optical circulator.
Claim 49
Dependent Claim
34 words
The angled-dual-axis confocal scanning system of claim 47 wherein said second port of said second optical circulator is optically coupled to said second port of said first optical circulator via a third optical fiber.
Claim 50
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 47 further comprising a light source, wherein said first port of said second optical circulator is optically coupled to said light source.
Claim 51
Dependent Claim
24 words
The angled-dual-axis confocal scanning system of claim 49 further comprising an optical detector, optically coupled to said third port of said second optical circulator.
Claim 52
Dependent Claim
70 words
The angled-dual-axis confocal scanning system of claim 49 wherein said light source is optically coupled to said first port of said second optical circulator via a beam-splitting means, such that said beam-splitting means routes a portion of an output beam emitted from said light source to said first port of said second optical circulator, providing said illumination beam, and wherein a remainder of said output beam provides a reference beam.
Claim 53
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 51 wherein said beam-splitting means comprises a first fiber-optic coupler, and wherein said reference beam is routed to a reference optical fiber.
Claim 54
Dependent Claim
41 words
The angled-dual-axis confocal scanning system of claim 52 further comprising a detection optical fiber optically coupled to said third port of second optical circulator, wherein said reference optical fiber and said detection optical fiber are coupled by a second fiber-optic coupler.
Claim 55
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 53 further comprising a frequency shifting means optically coupled to said reference optical fiber, for shifting the frequency of said reference beam.
Claim 56
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 53 further comprising a frequency shifting means optically coupled to said detection optical fiber, for shifting the frequency of said observation beam.
Claim 57
Dependent Claim
25 words
The angled-dual-axis confocal scanning system of claim 53 further comprising an optical amplifier optically coupled to said detection optical fiber, for amplifying said observation beam.
Claim 58
Dependent Claim
22 words
The angled-dual-axis confocal scanning system of claim 53 further comprising an adjustable optical delay device optically coupled to said detection optical fiber.
Claim 59
Dependent Claim
22 words
The angled-dual-axis confocal scanning system of claim 53 further comprising an adjustable optical delay device optically coupled to said reference optical fiber.
Claim 60
Dependent Claim
23 words
The angled-dual-axis confocal scanning system of claim 53 further comprising one or more optical detectors, optically coupled to said second fiber optic coupler.
Claim 61
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 51 further comprising a frequency shifting means optically coupled to said second optical fiber, for shifting the frequency of said observation beam.
Claim 62
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 51 further comprising a frequency shifting means optically coupled to said first optical fiber, for shifting the frequency of said illumination beam.
Claim 63
Dependent Claim
43 words
The angled-dual-axis confocal scanning system of claim 51 further comprising a frequency shifting means in optical communication with said second port of said second optical circulator and said second port of said first optical circulator, for shifting the frequency of said observation beam.
Claim 64
Dependent Claim
33 words
The angled-dual-axis confocal scanning system of claim 51 further comprising a frequency shifting means optically coupled to said third port of said second optical circulator, for shifting the frequency of said observation beam.
Claim 65
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 51 further comprising a frequency shifting means in optical communication with said beam-splitting means, for shifting the frequency of said reference beam.
Claim 66
Dependent Claim
25 words
The angled-dual-axis confocal scanning system of claim 51 further comprising an optical amplifier optically coupled to said second optical fiber, for amplifying said observation beam.
Claim 67
Dependent Claim
29 words
The angled-dual-axis confocal scanning system of claim 51 further comprising an optical amplifier optically coupled to said third port of said second optical circulator, for amplifying said observation beam.
Claim 68
Dependent Claim
24 words
The angled-dual-axis confocal scanning system of claim 51 further comprising an optical delay device for adjusting an optical path length of said reference beam.
Claim 69
Dependent Claim
24 words
The angled-dual-axis confocal scanning system of claim 51 further comprising an optical delay device for adjusting an optical path length of said observation beam.
Claim 70
Independent Claim
216 words
A method of performing angled-dual-axis confocal scanning microscopy within a sample, comprising: a) transmitting an illumination beam emerging from a first end of a first optical fiber to an angled-dual-axis focusing means; b) directing said illumination beam from said angled-dual-axis focusing means to an illumination focal volume along an illumination axis within said sample; c) using said angled-dual-axis focusing means to collect an observation beam emanated from an observation focal volume along an observation axis within said sample, wherein said illumination axis and said observation axis intersect at an angle within said sample, such that said illumination focal volume and said observation focal volume intersect optimally at a confocal overlapping volume; d) focusing said observation beam to a first end of a second optical fiber; e) filling a space between said angled-dual-axis focusing means and said sample with a fluid substantially transparent to said illumination beam and said observation beam, and wherein said fluid has an index of refraction that is substantially the same as an index of refraction of said sample; and f) moving said first ends of said first and second optical fibers and said angled-dual-axis focusing means in unity relative to said sample in a vertical direction, such that said confocal overlapping volume deepens progressively into said sample, thereby producing a vertical scan.
Claim 71
Independent Claim
216 words
A method of performing angled-dual-axis confocal scanning microscopy within a sample, comprising: a) transmitting an illumination beam emerging from a first end of a first optical fiber to an angled-dual-axis focusing means; b) directing said illumination beam from said angled-dual-axis focusing means to an illumination focal volume along an illumination axis within said sample; c) using said angled-dual-axis focusing means to collect an observation beam emanated from an observation focal volume along an observation axis within said sample, wherein said illumination axis and said observation axis intersect at an angle within said sample, such that said illumination focal volume and said observation focal volume intersect optimally at a confocal overlapping volume; d) focusing said observation beam to a first end of a second optical fiber; e) filling a space between said angled-dual-axis focusing means and said sample with a fluid substantially transparent to said illumination beam and said observation beam, and wherein said fluid has an index of refraction that is substantially the same as an index of refraction of said sample; and f) moving said first ends of said first and second optical fibers and said angled-dual-axis focusing means in unity relative to said sample in a vertical direction, such that said confocal overlapping volume deepens progressively into said sample, thereby producing a vertical scan.
Claim 72
Dependent Claim
13 words
The method of claim 69 wherein said vertical scan comprises a vertical-line scan.
Claim 73
Dependent Claim
28 words
The method of claim 70 further comprising the step of translating said sample incrementally along a transverse direction perpendicular to said vertical direction, after completing said vertical-line scan.
Claim 74
Dependent Claim
41 words
The method of claim 69 further comprising the step of translating said sample along transverse directions perpendicular to said vertical direction, such that said confocal overlapping volume effectively moves across said sample along said transverse directions, thereby producing a transverse scan.
Claim 75
Dependent Claim
33 words
The method of claim 72 wherein said transverse scan comprises a transverse cross-section scan, and wherein said method further comprises the step of repeating said step f) after completing said transverse cross-section scan.
Claim 76
Dependent Claim
30 words
The method of claim 69 further comprising the step of disposing a window assembly between said angled-dual-axis focusing means and said fluid for passage of said illumination and observation beams.
Claim 77
Dependent Claim
29 words
The method of claim 69 further comprising the step of disposing a substantially transparent window between said fluid and said sample for passage of said illumination and observation beams.
Claim 78
Dependent Claim
30 words
The method of claim 69 further comprising the step of mechanically coupling said first ends of said first and second optical fibers and said angled-dual-axis focusing means to a substrate.
Claim 79
Dependent Claim
27 words
The method of claim 76 wherein said substrate is a silicon substrate, and wherein said method further comprises the step of etching V-grooves on said silicon substrate.
Claim 80
Dependent Claim
57 words
The method of claim 69 further comprising the step of coupling a second end of said first optical fiber to a light source and a second end of said second optical fiber to an optical detector, such that said illumination beam is transmitted from said light source and said observation beam is routed to said optical detector.
Claim 81
Dependent Claim
42 words
The method of claim 69 further comprising the step of coupling a second end of said first optical fiber to a third port of and a second end of said second optical fiber to a first port of a three-port optical circulator.
Claim 82
Dependent Claim
67 words
The method of claim 79 further comprising the step of coupling a second port of said optical circulator to a first output aperture of a self-detecting light source and coupling a second output aperture of said self-detecting light source to an optical detector, such that said illumination beam is transmitted from said first output aperture and said observation beam is back coupled to said first output aperture.
Claim 83
Dependent Claim
79 words
The method of claim 79 further comprising the step of coupling a second port of said optical circulator to a second port of an auxiliary three-port optical circulator, a first port of said auxiliary optical circulator to a light source, and a third port of said auxiliary optical circular to a first end of a detection optical fiber, such that said illumination beam originates from said light source and said observation beam is routed to said detection optical fiber.
Claim 84
Dependent Claim
77 words
The method of claim 81 further comprising the step of coupling a beam-splitting means between said light source and said first port of said auxiliary optical circulator, such that said beam-splitting means routes a portion of an output beam emitted from said light source to said first port of said auxiliary optical circulator, providing said illumination beam, and a remainder of said output beam to a first end of a reference optical fiber, providing a reference beam.
Claim 85
Dependent Claim
23 words
The method of claim 82 further comprising the step of combining and detecting coherent interference between said reference beam and said observation beam.
Claim 86
Dependent Claim
33 words
The method of claim 83 further comprising the step of shifting the frequency of said observation beam and using heterodyne detection to detect coherent interference between said reference beam and said observation beam.
Claim 87
Dependent Claim
33 words
The method of claim 83 further comprising the step of shifting the frequency of said reference beam and using heterodyne detection to detect coherent interference between said reference beam and said observation beam.
Claim 88
Dependent Claim
15 words
The method of claim 83 further comprising the step of implementing a balanced detection scheme.
Claim 89
Dependent Claim
34 words
The method of claim 83 further comprising the step of adjusting an optical path length of said observation beam relative to an optical path length of said reference beam, to provide said coherent interference.
Claim 90
Dependent Claim
34 words
The method of claim 83 further comprising the step of adjusting an optical path length of said reference beam relative to an optical path length of said observation beam, to provide said coherent interference.
Claim 91
Dependent Claim
34 words
The method of claim 83 further comprising the step of adjusting an optical path length of said illumination beam relative to an optical path length of said reference beam, to provide said coherent interference.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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