Optical coherence tomography with 3d coherence scanning
View Patent ↗Optical coherence tomography with 3D coherence scanning is disclosed, using at least three fibers ( 201, 202, 203 ) for object illumination and collection of backscattered light. Fiber tips ( 1, 2, 3 ) are located in a fiber tip plane ( 71 ) normal to the optical axis ( 72 ). Light beams emerging from the fibers overlap at an object ( 122 ) plane, a subset of intersections of the beams with the plane defining field of view ( 266 ) of the optical coherence tomography apparatus. Interference of light emitted and collected by the fibers creates a 3D fringe pattern. The 3D fringe pattern is scanned dynamically over the object by phase shift delays ( 102, 104 ) controlled remotely, near ends of the fibers opposite the tips of the fibers, and combined with light modulation. The dynamic fringe pattern is backscattered by the object, transmitted to a light processing system ( 108 ) such as a photo detector, and produces an AC signal on the output of the light processing system ( 108 ). Phase demodulation of the AC signal at selected frequencies and signal processing produce a measurement of a 3D profile of the object.
1. An optical coherence tomography apparatus, comprising:
a first optical fiber ( 201 ), comprising a first fiber tip ( 1 ) thereof;
a second optical fiber ( 202 ), comprising a second fiber tip ( 2 ) thereof displaced from said first fiber tip ( 1 ) substantially in a fiber tip plane ( 71 ) substantially normal to an optical axis ( 72 ) of said apparatus; and
a phase delay φ x module ( 102 ) introducing a relative phase delay between said first optical fiber ( 201 ) and said second optical fiber ( 202 ); wherein:
adjustment of said phase delay φ x module ( 102 ) enables scanning of an object ( 122 ) in a one-dimensional direction parallel to the displacement between said first fiber tip ( 1 ) and said second fiber tip ( 2 ) and
not counting any collection fibers ( 204 ), said apparatus consists of no more optical fibers than said two optical fibers for said scanning in said direction parallel to said displacement between said first fiber tip ( 1 ) and said second fiber tip ( 2 ).
2. The apparatus of claim 1 , further comprising:
a third optical fiber ( 203 ), comprising a third fiber tip ( 3 ) thereof displaced from said first fiber tip ( 1 ) and said second fiber tip ( 2 ) substantially in said fiber tip plane ( 71 ), such that said first fiber tip ( 1 ), second fiber tip ( 2 ) and third fiber tip ( 3 ) define said fiber tip plane ( 71 ); and
a phase delay φ y module ( 104 ) introducing a relative phase delay between said first optical fiber ( 201 ) and said third optical fiber ( 203 ); wherein:
adjustment of said phase delay φ y module ( 104 ) enables scanning of the object ( 122 ) in a direction parallel to the displacement between said first fiber tip ( 1 ) and said third fiber tip ( 3 ); and
not counting any collection fibers ( 204 ), said apparatus consists of no more optical fibers than said three optical fibers for said scanning through a 2-dimensional plane parallel to said fiber tip plane ( 71 ); whereby:
said adjustment of said phase delay φ x module ( 102 ) in combination with said adjustment of said phase delay φ y module ( 104 ) enables scanning of the object ( 122 ) through said 2-dimensional plane parallel to said fiber tip plane ( 71 ).
3. The apparatus of claim 1 , further comprising:
a phase delay φ z module ( 106 ) for introducing a relative phase delay between a reference optical path ( 107 ) and an object optical path ( 109 ) of said apparatus; wherein:
adjustment of said phase delay φ z module ( 106 ) enables scanning of the object ( 122 ) in a direction substantially parallel to the optical axis ( 72 ); whereby:
said adjustment of said phase delay φ x module ( 102 ) in combination with said adjustment of said phase delay φ z module ( 106 ) enables scanning of the object ( 122 ) through a 2-dimensional plane defined by the displacement between said first fiber tip ( 1 ) and said second fiber tip ( 2 ), and the optical axis ( 72 ).
4. The apparatus of claim 2 , further comprising:
a phase delay φ z module ( 106 ) for introducing a relative phase delay between a reference optical path ( 107 ) and an object optical path ( 109 ) of said apparatus; wherein:
adjustment of said phase delay φ z module ( 106 ) enables scanning of the object ( 122 ) in a direction substantially parallel to the optical axis ( 72 ); whereby:
said adjustment of said phase delay φ x module ( 102 ) in combination with said adjustment of said phase delay φ y module ( 104 ) in further combination with said adjustment of said phase delay φ z module ( 106 ) enables scanning of the object ( 122 ) through a 3-dimensional volume.
5. The apparatus of claim 2 , further comprising:
a first modulator ( 230 ) for modulation of light passed through said first optical fiber ( 201 );
a second modulator ( 232 ) for modulation of light passed through said second optical fiber ( 202 );
a third modulator ( 234 ) for modulation of light passed through said third optical fiber further ( 203 ); and
a non-linear light processing system ( 108 ) of at least of second power with respect to an intensity of light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ), thereby producing a localized, 2-dimensional instrumental function.
6. The apparatus of claim 3 , further comprising:
a first modulator ( 230 ) for modulation of light passed through said first optical fiber ( 201 );
a second modulator ( 232 ) for modulation of light passed through said second optical fiber ( 202 );
a fourth modulator ( 236 ) for modulation of light passed through said reference optical path ( 107 ); and
a non-linear light processing system of at least of second power with respect to an intensity of light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said fourth modulator ( 236 ), thereby producing a localized, 2-dimensional instrumental function.
7. The apparatus of claim 4 , further comprising:
a first modulator ( 230 ) for modulation of light passed through said first optical fiber ( 201 );
a second modulator ( 232 ) for modulation of light passed through said second optical fiber ( 202 );
a third modulator ( 234 ) for modulation of light passed through said third optical fiber further ( 203 );
a fourth modulator ( 236 ) for modulation of light passed through said reference optical path ( 107 ); and
a non-linear light processing system ( 108 ) of at least of third power with respect to an intensity of light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ), and said fourth modulator ( 236 ), thereby producing a localized, 3-dimensional instrumental function.
8. The apparatus of claim 2 , wherein:
said first fiber tip ( 1 ), said second fiber tip ( 2 ) and said third fiber tip ( 3 ) are configured such that light emitted therefrom substantially overlaps and is substantially unfocused at an intended distance of the object ( 122 ) from said first, second, and third fiber tips ( 1 , 2 , 3 ); whereby:
said first, second, and third fiber tips ( 1 , 2 , 3 ) are enabled to probe more closely to the object ( 122 ) than would be possible if the light emitted therefrom were to be focused on a single focal spot of the object ( 122 ).
9. The apparatus of claim 5 , wherein:
said first fiber tip ( 1 ), said second fiber tip ( 2 ) and said third fiber tip ( 3 ) are configured such that light emitted therefrom substantially overlaps and is substantially unfocused at an intended distance of the object ( 122 ) from said first, second, and third fiber tips ( 1 , 2 , 3 ); whereby:
said first, second, and third fiber tips ( 1 , 2 , 3 ) are enabled to probe more closely to the object ( 122 ) than would be possible if the light emitted therefrom were to be focused on a single focal spot of the object ( 122 ).
10. The apparatus of claim 7 , wherein:
said first fiber tip ( 1 ), said second fiber tip ( 2 ) and said third fiber tip ( 3 ) are configured such that light emitted therefrom substantially overlaps and is substantially unfocused at an intended distance of the object ( 122 ) from said first, second, and third fiber tips ( 1 , 2 , 3 ); whereby:
said first, second, and third fiber tips ( 1 , 2 , 3 ) are enabled to probe more closely to the object ( 122 ) than would be possible if the light emitted therefrom were to be focused on a single focal spot of the object ( 122 ).
11. The apparatus of claim 5 , said non-linear light processing system ( 108 ) comprising a signal intensity multiplier multiplying the light intensities.
12. The apparatus of claim 5 , said non-linear light processing system ( 108 ) comprising a photo detector outputting an electric signal proportional to at least said second power of the light intensities.
13. The apparatus of claim 5 , said non-linear light processing system ( 108 ) comprising a digital processor processing the light intensities.
14. The apparatus of claim 7 , said non-linear light processing system ( 108 ) comprising a signal intensity multiplier multiplying the light intensities.
15. The apparatus of claim 7 , said non-linear light processing system ( 108 ) comprising a photo detector outputting an electric signal proportional to at least said third power of the light intensities.
16. The apparatus of claim 7 , said non-linear light processing system ( 108 ) comprising a digital processor processing the light intensities.
17. The apparatus of claim 2 , further comprising:
a fourth collection optical fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ), optically connected with an object optical path ( 109 ) of said apparatus.
18. The apparatus of claim 4 , further comprising:
a fourth optical collection fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ), optically connected with said object optical path ( 109 ).
19. The apparatus of claim 18 :
said first optical fiber ( 201 ) comprising single mode fiber;
said second optical fiber ( 202 ) comprising single mode fiber;
said third optical fiber ( 203 ) comprising single mode fiber; and
said fourth optical fiber ( 204 ) comprising multi mode fiber.
20. The apparatus of claim 5 , further comprising:
a fourth optical collection fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ), optically connected with an object optical path ( 109 ) of said apparatus.
21. The apparatus of claim 20 :
said first optical fiber ( 201 ) comprising single mode fiber;
said second optical fiber ( 202 ) comprising single mode fiber;
said third optical fiber ( 203 ) comprising single mode fiber; and
said fourth optical fiber ( 204 ) comprising multi mode fiber.
22. The apparatus of claim 7 , further comprising:
a fourth optical collection fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ), optically connected with said object optical path ( 109 ).
23. The apparatus of claim 22 :
said first optical fiber ( 201 ) comprising single mode fiber;
said second optical fiber ( 202 ) comprising single mode fiber;
said third optical fiber ( 203 ) comprising single mode fiber; and
said fourth optical fiber ( 204 ) comprising multi mode fiber.
24. The apparatus of claim 22 , wherein:
said first fiber tip ( 1 ), said second fiber tip ( 2 ) and said third fiber tip ( 3 ) are configured such that light emitted therefrom substantially overlaps and is substantially unfocused at an intended distance of the object ( 122 ) from said first, second, and third fiber tips ( 1 , 2 , 3 ); whereby:
said first, second, and third fiber tips ( 1 , 2 , 3 ) are enabled to probe more closely to the object ( 122 ) than would be possible if the light emitted therefrom were to be focused on a single focal spot of the object ( 122 ).
25. The apparatus of claim 2 , further comprising:
at least one of said first optical fiber ( 201 ), said second optical fiber ( 202 ), and said third optical fiber ( 203 ) optically connected with an object optical path ( 109 ) of said apparatus.
26. The apparatus of claim 4 , further comprising:
at least one of said first optical fiber ( 201 ), said second optical fiber ( 202 ), and said third optical fiber ( 203 ) optically connected with said object optical path ( 109 ).
27. The apparatus of claim 7 , further comprising:
at least one of said first optical fiber ( 201 ), said second optical fiber ( 202 ), and said third optical fiber ( 203 ) optically connected with said object optical path ( 109 ).
28. The apparatus of claim 4 , further comprising:
light input into said apparatus, split into said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ); and
light output from said apparatus, joined from said reference optical path ( 107 ) and said object optical path ( 109 ).
29. The apparatus of claim 4 , further comprising:
light input into said apparatus, split into said reference optical path ( 107 ) and said object optical path ( 109 ); and
light output from said apparatus, joined from said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ).
30. The apparatus of claim 7 , further comprising:
light input into said apparatus, split into said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ); and
light output from said apparatus, joined from said reference optical path ( 107 ) and said object optical path ( 109 ).
31. The apparatus of claim 7 , further comprising:
light input into said apparatus, split into said reference optical path ( 107 ) and said object optical path ( 109 ); and
light output from said apparatus, joined from said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ).
32. The apparatus of claim 22 , further comprising:
light input into said apparatus, split into said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ); and
light output from said apparatus, joined from said reference optical path ( 107 ) and said object optical path ( 109 ).
33. The apparatus of claim 22 , further comprising:
light input into said apparatus, split into said reference optical path ( 107 ) and said object optical path ( 109 ); and
light output from said apparatus, joined from said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ).
34. The apparatus of claim 5 , said non-linear light processing system ( 108 ) further comprising:
at least two filters ( 152 , 154 ) filtering around different central wavelengths, the light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ), wherein:
light emerging from each of said at least two filters ( 152 , 154 ) is measured substantially simultaneously and correlated, thereby providing an expanded spectral range for measurement, and redundant measurement with improved signal to noise ratio.
35. The apparatus of claim 34 , said non-linear light processing system ( 108 ) further comprising a reference tap ( 156 ) tapping the light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ), to reduce the effect of any possible light intensity instability.
36. The apparatus of claim 7 , said non-linear light processing system ( 108 ) further comprising:
at least two filters ( 152 , 154 ) filtering around different central wavelengths, the light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ), wherein:
light emerging from each of said at least two filters ( 152 , 154 ) is measured substantially simultaneously and correlated, thereby providing an expanded spectral range for measurement, and redundant measurement with improved signal to noise ratio.
37. The apparatus of claim 36 , said non-linear light processing system ( 108 ) further comprising a reference tap ( 156 ) tapping the light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ), to reduce the effect of any possible light intensity instability.
38. The apparatus of claim 5 , further comprising:
light input into said apparatus from at least two light sources ( 110 ).
39. The apparatus of claim 38 , said at least two light sources ( 110 ) comprising substantially identical wavelength spectra, wherein:
intensities of said two light sources ( 110 ) add incoherently; and
said light input thereby comprises a higher intensity equal to intensities of said at least two light sources ( 110 ).
40. The apparatus of claim 38 , said at least two light sources ( 110 ) comprising different wavelength spectra, wherein:
said light input thereby comprises a wider spectrum than the separate spectra of said at least two light sources ( 110 ), resulting in shorter coherence length and improved spatial resolution.
41. The apparatus of claim 40 , further comprising at least two light source modulators ( 191 ), each said light source modulator ( 191 ) modulating light from one of said at least two light sources ( 110 ).
42. The apparatus of claim 7 , further comprising:
light input into said apparatus from at least two light sources ( 110 ).
43. The apparatus of claim 42 , said at least two light sources ( 110 ) comprising substantially identical wavelength spectra, wherein:
intensities of said two light sources ( 110 ) add incoherently; and
said light input thereby comprises a higher intensity equal to intensities of said at least two light sources ( 110 ).
44. The apparatus of claim 42 , said at least two light sources ( 110 ) comprising different wavelength spectra, wherein:
said light input thereby comprises a wider spectrum than the separate spectra of said at least two light sources ( 110 ), resulting in shorter coherence length and improved spatial resolution.
45. The apparatus of claim 44 , further comprising at least two light source modulators ( 191 ), each said light source modulator ( 191 ) modulating light from one of said at least two light sources ( 110 ).
46. An optical coherence tomography apparatus, comprising:
a first optical fiber ( 201 ), comprising a first fiber tip ( 1 ) thereof;
a second optical fiber ( 202 ), comprising a second fiber tip ( 2 ) thereof displaced from said first fiber tip ( 1 ) substantially in a fiber tip plane ( 71 ) substantially normal to an optical axis ( 72 ) of said apparatus;
a third optical fiber ( 203 ), comprising a third fiber tip ( 3 ) thereof displaced from said first fiber tip ( 1 ) and said second fiber tip ( 2 ) substantially in said fiber tip plane ( 71 ), such that said first fiber tip ( 1 ), second fiber tip ( 2 ) and third fiber tip ( 3 ) define said fiber tip plane ( 71 );
a first modulator ( 230 ) for modulation of light passed through said first optical fiber ( 201 );
a second modulator ( 232 ) for modulation of light passed through said second optical fiber ( 202 );
a third modulator ( 234 ) for modulation of light passed through said third optical fiber further ( 203 ); and
a non-linear light processing system ( 108 ) of at least of second power with respect to an intensity of light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ), thereby producing a localized, 2-dimensional instrumental function; wherein
not counting any collection fibers ( 204 ), said apparatus consists of no more optical fibers than said three optical fibers for said scanning through a 2-dimensional plane parallel to said fiber tip plane ( 71 ).
47. The apparatus of claim 46 , further comprising:
a reference optical path ( 107 );
a fourth modulator ( 236 ) for modulation of light passed through said reference optical path ( 107 ); and
said non-linear light processing system ( 108 ) of at least of third power with respect to an intensity of light passed through said first modulator ( 230 ), said second modulator ( 232 ), said third modulator ( 234 ), and said fourth modulator ( 236 ), thereby producing a localized, 3-dimensional instrumental function.
48. A probe head ( 270 ) apparatus for use in connection with an optical coherence tomography apparatus, comprising:
a first optical fiber ( 201 ), comprising a first fiber tip ( 1 ) thereof;
a second optical fiber ( 202 ), comprising a second fiber tip ( 2 ) thereof displaced from said first fiber tip ( 1 ) substantially in a fiber tip plane ( 71 ) substantially normal to an optical axis ( 72 ) of said probe head ( 270 );
a third optical fiber ( 203 ), comprising a third fiber tip ( 3 ) thereof displaced from said first fiber tip ( 1 ) and said second fiber tip ( 2 ) substantially in said fiber tip plane ( 71 ), such that said first fiber tip ( 1 ), second fiber tip ( 2 ) and third fiber tip ( 3 ) define said fiber tip plane ( 71 ); and
an optical connector ( 272 ) for connecting said probe head ( 270 ) to and disconnecting said probe head ( 270 ) from, said optical coherence tomography apparatus; wherein
not counting any collection fibers ( 204 ), said probe head consists of no more optical fibers than said three optical fibers.
49. The probe head ( 270 ) apparatus of claim 48 , wherein:
said first fiber tip ( 1 ), said second fiber tip ( 2 ) and said third fiber tip ( 3 ) are configured such that light emitted therefrom substantially overlaps and is substantially unfocused at an intended distance of an object ( 122 ) to be scanned from said first, second, and third fiber tips ( 1 , 2 , 3 ).
50. The probe head ( 270 ) apparatus of claim 48 , further comprising:
a fourth optical collection fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ), wherein:
said fourth fiber tip ( 4 ) is configured to receive light backscattered from the object ( 122 ).
51. The probe head ( 270 ) apparatus of claim 49 , further comprising:
a fourth optical collection fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ), wherein:
said fourth fiber tip ( 4 ) is configured to receive light backscattered from the object ( 122 ).
52. The probe head ( 270 ) apparatus of claim 50 :
said first optical fiber ( 201 ) comprising single mode fiber;
said second optical fiber ( 202 ) comprising single mode fiber;
said third optical fiber ( 203 ) comprising single mode fiber; and
said fourth optical fiber ( 204 ) comprising multi mode fiber.
53. The probe head ( 270 ) apparatus of claim 51 :
said first optical fiber ( 201 ) comprising single mode fiber;
said second optical fiber ( 202 ) comprising single mode fiber;
said third optical fiber ( 203 ) comprising single mode fiber; and
said fourth optical fiber ( 204 ) comprising multi mode fiber.
54. The probe head ( 270 ) apparatus of claim 49 , further comprising:
beveling on at least two of said first, second, and third optical fibers ( 201 , 202 , 203 ), causing the light emitted therefrom to substantially overlap at said intended distance of the object ( 122 ).
55. The probe head ( 270 ) apparatus of claim 51 , further comprising:
beveling on at least two of said first, second, and third optical fibers ( 201 , 202 , 203 ) causing the light emitted therefrom to substantially overlap at said intended distance of the object ( 122 ).
56. The probe head ( 270 ) apparatus of claim 49 , further comprising:
a probe head tip refractory element ( 262 ) causing the light emitted from said first, second, and third optical fibers ( 201 , 202 , 203 ) to substantially overlap at said intended distance of the object ( 122 ).
57. The probe head ( 270 ) apparatus of claim 51 , further comprising:
a probe head tip refractory element ( 262 ) causing the light emitted from said first, second, and third optical fibers ( 201 , 202 , 203 ) to substantially overlap at said intended distance of the object ( 122 ).
58. The probe head ( 270 ) apparatus of claim 57 , further comprising:
a pellet connected to said fourth fiber tip ( 4 ) between said fourth fiber tip ( 4 ) and said probe head tip refractory element ( 262 ).
59. An optical coherence tomography method, using an optical coherence tomography apparatus therefor, comprising the steps of:
providing a first optical fiber ( 201 ), comprising a first fiber tip ( 1 ) thereof;
providing a second optical fiber ( 202 ), comprising a second fiber tip ( 2 ) thereof displaced from said first fiber tip ( 1 ) substantially in a fiber tip plane ( 71 ) substantially normal to an optical axis ( 72 ) of said apparatus; and:
scanning an object ( 122 ) in a one-dimensional direction parallel to the displacement between said first fiber tip ( 1 ) and said second fiber tip ( 2 ) by adjusting a relative phase delay φ x ( 102 ) between said first optical fiber ( 201 ) and said second optical fiber ( 202 ); and
not counting any collection fibers ( 204 ), scanning in said direction parallel to said displacement between said first fiber tip ( 1 ) and said second fiber tip ( 2 ) using no more optical fibers than said two optical fibers.
60. The method of claim 59 , further comprising the steps of:
providing a third optical fiber ( 203 ), comprising a third fiber tip ( 3 ) thereof displaced from said first fiber tip ( 1 ) and said second fiber tip ( 2 ) substantially in said fiber tip plane ( 71 ), such that said first fiber tip ( 1 ), second fiber tip ( 2 ) and third fiber tip ( 3 ) define said fiber tip plane ( 71 );
scanning the object ( 122 ) in a direction parallel to the displacement between said first fiber tip ( 1 ) and said third fiber tip ( 3 ) by adjusting a relative phase delay φ y ( 104 ) between said first optical fiber ( 201 ) and said third optical fiber ( 203 ); and
not counting any collection fibers ( 204 ), scanning through a 2-dimensional plane parallel to said fiber tip plane ( 71 ) using no more optical fibers than said three optical fibers; whereby:
scanning of the object ( 122 ) through said 2-dimensional plane parallel to said fiber tip plane ( 71 ) is enabled by said adjusting said phase delay φ x ( 102 ) in combination with said adjusting said phase delay φ y ( 104 ).
61. The method of claim 59 , further comprising the step of:
scanning the object ( 122 ) in a direction substantially parallel to the optical axis ( 72 ) by adjusting a relative phase delay φ z ( 106 ) between a reference optical path ( 107 ) and an object optical path ( 109 ) of said apparatus; whereby:
scanning of the object ( 122 ) through a 2-dimensional plane defined by the displacement between said first fiber tip ( 1 ) and said second fiber tip ( 2 ), and the optical axis ( 72 ) is enabled by said adjusting said phase delay φ x ( 102 ) in combination with said adjusting said phase delay φ z ( 106 ).
62. The method of claim 60 , further comprising the step of:
scanning the object ( 122 ) in a direction substantially parallel to the optical axis ( 72 ) by adjusting a relative phase delay φ z ( 106 ) between a reference optical path ( 107 ) and an object optical path ( 109 ) of said apparatus; whereby:
scanning of the object ( 122 ) through a 3-dimensional volume is enabled by said adjusting said phase delay φ x ( 102 ) in combination with said adjusting said phase delay φ y ( 104 ) in further combination with said adjusting said phase delay φ z ( 106 ).
63. The method of claim 60 , further comprising the steps of:
modulating light passed through said first optical fiber ( 201 ) with a first modulation ( 230 );
modulating light passed through said second optical fiber ( 202 ) with a second modulation ( 232 );
modulating light passed through said third optical fiber further ( 203 ) with a third modulation ( 234 ); and
producing a localized, 2-dimensional instrumental function by non-linearly processing ( 108 ) to at least a second power with respect to intensity, light from said first modulation ( 230 ), said second modulation ( 232 ), and said third modulation ( 234 ).
64. The method of claim 61 , further comprising the steps of:
modulating light passed through said first optical fiber ( 201 ) with a first modulation ( 230 );
modulating light passed through said second optical fiber ( 202 ) with a second modulation ( 232 );
modulating light passed through said reference optical path ( 107 ) with a fourth modulation ( 236 ); and
producing a localized, 2-dimensional instrumental function by non-linearly processing ( 108 ) to at least a second power with respect to intensity, light from said first modulation ( 230 ), said second modulation ( 232 ), and said fourth modulation ( 232 ).
65. The method of claim 62 , further comprising the steps of:
modulating light passed through said first optical fiber ( 201 ) with a first modulation ( 230 );
modulating light passed through said second optical fiber ( 202 ) with a second modulation ( 232 );
modulating light passed through said third optical fiber further ( 203 ) with a third modulation ( 234 );
modulating light passed through said reference optical path ( 107 ) with a fourth modulation ( 236 ); and
producing a localized, 3-dimensional instrumental function by non-linearly processing ( 108 ) to at least a third power with respect to intensity, light from said first modulation ( 230 ), said second modulation ( 232 ), said third modulation ( 234 ), and said fourth modulation ( 232 ).
66. The method of claim 60 , further comprising the step of:
configuring said first fiber tip ( 1 ), said second fiber tip ( 2 ) and said third fiber tip ( 3 ) for overlapping light emitted therefrom substantially overlaps and is substantially unfocused at an intended distance of the object ( 122 ) from said first, second, and third fiber tips ( 1 , 2 , 3 ); whereby:
probing is enabled more closely to the object ( 122 ) with said first, second, and third fiber tips ( 1 , 2 , 3 ) than would be possible by focusing the light emitted therefrom on a single focal spot of the object ( 122 ).
67. The method of claim 63 , further comprising the step of:
configuring said first fiber tip ( 1 ), said second fiber tip ( 2 ) and said third fiber tip ( 3 ) for overlapping light emitted therefrom substantially overlaps and is substantially unfocused at an intended distance of the object ( 122 ) from said first, second, and third fiber tips ( 1 , 2 , 3 ); whereby:
probing is enabled more closely to the object ( 122 ) with said first, second, and third fiber tips ( 1 , 2 , 3 ) than would be possible by focusing the light emitted therefrom on a single focal spot of the object ( 122 ).
68. The method of claim 65 , further comprising the step of:
configuring said first fiber tip ( 1 ), said second fiber tip ( 2 ) and said third fiber tip ( 3 ) for overlapping light emitted therefrom substantially overlaps and is substantially unfocused at an intended distance of the object ( 122 ) from said first, second, and third fiber tips ( 1 , 2 , 3 ); whereby:
probing is enabled more closely to the object ( 122 ) with said first, second, and third fiber tips ( 1 , 2 , 3 ) than would be possible by focusing the light emitted therefrom on a single focal spot of the object ( 122 ).
69. The method of claim 63 , said step of non-linearly processing ( 108 ) comprising multiplying the light intensities.
70. The method of claim 63 , said step of non-linearly processing ( 108 ) comprising outputting an electric signal proportional to at least said second power of the light intensities, using a photo detector.
71. The method of claim 63 , said step of non-linearly processing ( 108 ) comprising digitally processing the light intensities.
72. The method of claim 65 , said step of non-linearly processing ( 108 ) comprising multiplying the light intensities.
73. The method of claim 65 , said step of non-linearly processing ( 108 ) comprising outputting an electric signal proportional to at least said second power of the light intensities, using a photo detector.
74. The method of claim 65 , said step of non-linearly processing ( 108 ) comprising digitally processing the light intensities.
75. The method of claim 60 , further comprising the steps of:
providing a fourth collection optical fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ); and
optically connecting said fourth optical fiber ( 204 ) with an object optical path ( 109 ) of said apparatus.
76. The method of claim 62 , further comprising the steps of:
providing a fourth collection optical fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ); and
optically connecting said fourth optical fiber ( 204 ) with an object optical path ( 109 ) of said apparatus.
77. The method of claim 76 , wherein:
said first optical fiber ( 201 ) comprises single mode fiber;
said second optical fiber ( 202 ) comprises single mode fiber;
said third optical fiber ( 203 ) comprises single mode fiber; and
said fourth optical fiber ( 204 ) comprises multi mode fiber.
78. The method of claim 63 , further comprising the steps of:
providing a fourth optical collection fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ); and
optically connecting said fourth optical fiber ( 204 ) with an object optical path ( 109 ) of said apparatus.
79. The method of claim 78 , wherein:
said first optical fiber ( 201 ) comprises single mode fiber;
said second optical fiber ( 202 ) comprises single mode fiber;
said third optical fiber ( 203 ) comprises single mode fiber; and
said fourth optical fiber ( 204 ) comprises multi mode fiber.
80. The method of claim 65 , further comprising the steps of:
providing a fourth optical collection fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ); and
optically connecting said fourth optical fiber ( 204 ) with an object optical path ( 109 ) of said apparatus.
81. The method of claim 80 , wherein:
said first optical fiber ( 201 ) comprises single mode fiber;
said second optical fiber ( 202 ) comprises single mode fiber;
said third optical fiber ( 203 ) comprises single mode fiber; and
said fourth optical fiber ( 204 ) comprises multi mode fiber.
82. The method of claim 80 , further comprising the step of:
configuring said first fiber tip ( 1 ), said second fiber tip ( 2 ) and said third fiber tip ( 3 ) for overlapping light emitted therefrom substantially overlaps and is substantially unfocused at an intended distance of the object ( 122 ) from said first, second, and third fiber tips ( 1 , 2 , 3 ); whereby:
probing is enabled more closely to the object ( 122 ) with said first, second, and third fiber tips ( 1 , 2 , 3 ) than would be possible by focusing the light emitted therefrom on a single focal spot of the object ( 122 ).
83. The method of claim 60 , further comprising the step of:
providing at least one of said first optical fiber ( 201 ), said second optical fiber ( 202 ), and said third optical fiber ( 203 ) optically connected with an object optical path ( 109 ) of said apparatus.
84. The method of claim 62 , further comprising the step of:
providing at least one of said first optical fiber ( 201 ), said second optical fiber ( 202 ), and said third optical fiber ( 203 ) optically connected with said object optical path ( 109 ).
85. The method of claim 65 , further comprising the step of:
providing at least one of said first optical fiber ( 201 ), said second optical fiber ( 202 ), and said third optical fiber ( 203 ) optically connected with said object optical path ( 109 ).
86. The method of claim 62 , further comprising the steps of:
splitting light input into said apparatus, into said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ); and
joining light output from said apparatus, from said reference optical path ( 107 ) and said object optical path ( 109 ).
87. The method of claim 62 , further comprising the steps of:
splitting light input into said apparatus, into said reference optical path ( 107 ) and said object optical path ( 109 ); and
joining light output from said apparatus, from said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ).
88. The method of claim 65 , further comprising the steps of:
splitting light input into said apparatus, into said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ); and
joining light output from said apparatus, from said reference optical path ( 107 ) and said object optical path ( 109 ).
89. The method of claim 65 , further comprising the steps of:
splitting light input into said apparatus, into said reference optical path ( 107 ) and said object optical path ( 109 ); and
joining light output from said apparatus, from said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ).
90. The method of claim 80 , further comprising the steps of:
splitting light input into said apparatus, into said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ); and
joining light output from said apparatus, from said reference optical path ( 107 ) and said object optical path ( 109 ).
91. The method of claim 80 , further comprising the steps of:
splitting light input into said apparatus, into said reference optical path ( 107 ) and said object optical path ( 109 ); and
joining light output from said apparatus, from said first optical fiber ( 201 ), said second optical fiber ( 202 ), said third optical fiber ( 203 ), and said reference optical path ( 107 ).
92. The method of claim 63 , said step of non-linearly processing ( 108 ) further comprising the steps of:
filtering around at least two different central wavelengths ( 152 , 154 ), the light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ); and
providing an expanded spectral range for measurement, and redundant measurement with improved signal to noise ratio, by measuring substantially simultaneously and correlating the filtered ( 152 , 154 ) light.
93. The method of claim 92 , said step of non-linearly processing ( 108 ) further comprising the step of:
reducing the effect of any possible light intensity instability by tapping ( 156 ) the light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ).
94. The method of claim 65 , said step of non-linearly processing ( 108 ) further comprising the steps of:
filtering around at least two different central wavelengths ( 152 , 154 ), the light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ); and
providing an expanded spectral range for measurement, and redundant measurement with improved signal to noise ratio, by measuring substantially simultaneously and correlating the filtered ( 152 , 154 ) light.
95. The method of claim 94 , said step of non-linearly processing ( 108 ) further comprising the step of:
reducing the effect of any possible light intensity instability by tapping the light passed through said first modulator ( 230 ), said second modulator ( 232 ), and said third modulator ( 234 ).
96. The method of claim 63 , further comprising the step of:
inputting light into said apparatus from at least two light sources ( 110 ).
97. The method of claim 96 , said at least two light sources ( 110 ) comprising substantially identical wavelength spectra, said light input thereby comprising a higher intensity equal to the intensity of said at least two light sources ( 110 ) by adding incoherently, intensities of said two light sources ( 110 ).
98. The method of claim 96 , the light input from said at least two light sources ( 110 ) comprising different wavelength spectra, said light input thereby comprising a wider spectrum than the separate spectra of said at least two light sources ( 110 ), resulting in shorter coherence length and improved spatial resolution.
99. The method of claim 98 , further comprising the step of:
light source modulating ( 191 ) modulating light from each of said at least two light sources ( 110 ).
100. The method of claim 65 , further comprising the step of:
inputting light into said apparatus from at least two light sources ( 110 ).
101. The method of claim 100 , said at least two light sources ( 110 ) comprising substantially identical wavelength spectra, said light input thereby comprising a higher intensity equal to the intensity of said at least two light sources ( 110 ) by adding incoherently, intensities of said two light sources ( 110 ).
102. The method of claim 100 , the light input from said at least two light sources ( 110 ) comprising different wavelength spectra, said light input thereby comprising a wider spectrum than the separate spectra of said at least two light sources ( 110 ), resulting in shorter coherence length and improved spatial resolution.
103. The method of claim 102 , further comprising the step of:
light source modulating ( 191 ) modulating light from each of said at least two light sources ( 110 ).
104. An optical coherence tomography method, using an optical coherence tomography apparatus therefor, comprising the steps of:
providing a first optical fiber ( 201 ), comprising a first fiber tip ( 1 ) thereof;
providing a second optical fiber ( 202 ), comprising a second fiber tip ( 2 ) thereof displaced from said first fiber tip ( 1 ) substantially in a fiber tip plane ( 71 ) substantially normal to an optical axis ( 72 ) of said apparatus;
providing a third optical fiber ( 203 ), comprising a third fiber tip ( 3 ) thereof displaced from said first fiber tip ( 1 ) and said second fiber tip ( 2 ) substantially in said fiber tip plane ( 71 ), such that said first fiber tip ( 1 ), second fiber tip ( 2 ) and third fiber tip ( 3 ) define said fiber tip plane ( 71 );
modulating light passed through said first optical fiber ( 201 ) with a first modulation ( 230 );
modulating light passed through said second optical fiber ( 202 ) with a second modulation ( 232 );
modulating light passed through said third optical fiber further ( 203 ) with a third modulation ( 234 ); producing a localized, 2-dimensional instrumental function by non-linearly processing ( 108 ) to at least a second power with respect to intensity, light from said first modulation ( 230 ), said second modulation ( 232 ), and said third modulation ( 234 ); and
not counting any collection fibers ( 204 ), scanning through a 2-dimensional plane parallel to said fiber tip plane ( 71 ) using no more optical fibers than said three optical fibers.
105. The method of claim 104 , further comprising the steps of:
modulating light passed through a reference optical path ( 107 ) of said apparatus with a fourth modulation ( 236 ); and
producing a localized, 3-dimensional instrumental function by non-linearly processing ( 108 ) to at least a third power with respect to intensity, light from said first modulation ( 230 ), said second modulation ( 232 ), said third modulation ( 234 ), and said fourth modulation ( 232 ).
106. A method for using a probe head ( 270 ) apparatus in connection with an optical coherence tomography apparatus, comprising the steps of:
providing a first optical fiber ( 201 ) of said probe head ( 270 ), comprising a first fiber tip ( 1 ) thereof;
providing a second optical fiber ( 202 ) of said probe head ( 270 ), comprising a second fiber tip ( 2 ) thereof displaced from said first fiber tip ( 1 ) substantially in a fiber tip plane ( 71 ) substantially normal to an optical axis ( 72 ) of said probe head ( 270 );
providing a third optical fiber ( 203 ) of said probe head ( 270 ), comprising a third fiber tip ( 3 ) thereof displaced from said first fiber tip ( 1 ) and said second fiber tip ( 2 ) substantially in said fiber tip plane ( 71 ), such that said first fiber tip ( 1 ), second fiber tip ( 2 ) and third fiber tip ( 3 ) define said fiber tip plane ( 71 ); and
connecting and disconnecting ( 272 ) said probe head ( 270 ) to and from said optical coherence tomography apparatus; wherein
not counting any collection fibers ( 204 ), said probe head consists of no more optical fibers than said three optical fibers.
107. The method of claim 106 , further comprising the step of:
configuring said first fiber tip ( 1 ), said second fiber tip ( 2 ) and said third fiber tip ( 3 ) for overlapping light emitted therefrom substantially overlaps and is substantially unfocused at an intended distance of an object ( 122 ) to be scanned from said first, second, and third fiber tips ( 1 , 2 , 3 ).
108. The method of claim 106 , further comprising the steps of:
providing a fourth optical collection fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ), and
configuring said fourth fiber tip ( 4 ) to receive light backscattered from the object ( 122 ).
109. The method of claim 107 , further comprising the steps of:
providing a fourth collection optical fiber ( 204 ), comprising a fourth fiber tip ( 4 ) thereof residing substantially in said fiber tip plane ( 71 ), and
configuring said fourth fiber tip ( 4 ) to receive light backscattered from the object ( 122 ).
110. The method of claim 108 , wherein:
said first optical fiber ( 201 ) comprises single mode fiber;
said second optical fiber ( 202 ) comprises single mode fiber;
said third optical fiber ( 203 ) comprises single mode fiber; and
said fourth optical fiber ( 204 ) comprises multi mode fiber.
111. The method of claim 109 , wherein:
said first optical fiber ( 201 ) comprises single mode fiber;
said second optical fiber ( 202 ) comprises single mode fiber;
said third optical fiber ( 203 ) comprises single mode fiber; and
said fourth optical fiber ( 204 ) comprises multi mode fiber.
112. The method of claim 107 , further comprising the step of:
causing the light emitted therefrom to substantially overlap at said intended distance of the object ( 122 ) by beveling at least two of said first, second, and third optical fibers ( 201 , 202 , 203 ).
113. The method of claim 109 , further comprising the step of:
causing the light emitted therefrom to substantially overlap at said intended distance of the object ( 122 ) by beveling at least two of said first, second, and third optical fibers ( 201 , 202 , 203 ).
114. The method of claim 107 , further comprising the step of:
causing the light emitted from said first, second, and third optical fibers ( 201 , 202 , 203 ) to substantially at said intended distance of the object ( 122 ), using a probe head tip refractory element ( 262 ).
115. The method of claim 109 , further comprising the step of:
causing the light emitted from said first, second, and third optical fibers ( 201 , 202 , 203 ) to substantially overlap at said intended distance of the object ( 122 ), using a probe head tip refractory element ( 262 ).
116. The method of claim 115 , further comprising the step of:
connecting a pellet to said fourth fiber tip ( 4 ) between said fourth fiber tip ( 4 ) and said probe head tip refractory element ( 262 ).