WO2007070565A2 - Interferometre paraboloide hors axe a eclairage hors axe - Google Patents

Interferometre paraboloide hors axe a eclairage hors axe Download PDF

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Publication number
WO2007070565A2
WO2007070565A2 PCT/US2006/047520 US2006047520W WO2007070565A2 WO 2007070565 A2 WO2007070565 A2 WO 2007070565A2 US 2006047520 W US2006047520 W US 2006047520W WO 2007070565 A2 WO2007070565 A2 WO 2007070565A2
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WO
WIPO (PCT)
Prior art keywords
light
illumination
optical fiber
paraboloid mirror
axis
Prior art date
Application number
PCT/US2006/047520
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English (en)
Other versions
WO2007070565A3 (fr
Inventor
Alex Klooster
Carl Aleksoff
Original Assignee
Coherix, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/301,320 external-priority patent/US7440114B2/en
Priority claimed from US11/299,548 external-priority patent/US20070133008A1/en
Application filed by Coherix, Inc. filed Critical Coherix, Inc.
Publication of WO2007070565A2 publication Critical patent/WO2007070565A2/fr
Publication of WO2007070565A3 publication Critical patent/WO2007070565A3/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G01B11/2441—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures using interferometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02001—Interferometers characterised by controlling or generating intrinsic radiation properties
    • G01B9/02007—Two or more frequencies or sources used for interferometric measurement

Definitions

  • This invention relates generally to the optical field, and more specifically to an improved system optical system for interferometric imaging.
  • FIGURE 1 is a schematic diagram of a prior art interferometer.
  • the particular interferometer shown in FIGURE 1 is conventionally called a Michelson interferometer, and has been used since the nineteenth century in optical experiments and measurements.
  • a light source 10 produces light that is collimated by passing through a lens system 11 to produce a parallel beam of light 12 that passes to a beamsplitter 13.
  • the beam of light 12 is partially reflected to a reference mirror 14 and partially transmitted to an object 15.
  • Light reflected from the reference mirror 14 partially passes through the beamsplitter to an image receiver 16.
  • Light reflected from the object is partially reflected from the beamsplitter 15 and is passed to the image receiver 16.
  • the image receiver 16 may be film, or may be an electronic photodetector or a CCD or a CMOS array, or any other image receiver known in the art.
  • both the reference mirror 14 and the object 15 are flat mirrors aligned perpendicular to the incoming light from beam 12, and the light path traversed by the light from the light source to the image receiver is identical, the light from both the reference mirror and the object mirror will be in phase, and the image receiver will show a uniformly bright image.
  • Such devices were the bane of undergraduate optics students before the advent of lasers, since the distances had to be equal to within distances measured by the wavelength of the light and the mirrors had to be aligned within microradians. Even with the advent of lasers with very long coherence lengths, such devices are subject to vibration, thermal drift of dimensions, shocks, etc.
  • FIGURE l The Michelson interferometer design of FIGURE l is useful to explain the many different types of interferometers known in the art.
  • the reference mirror 14 is moved back and forth in the direction of the arrow in FIGURE 1.
  • the phase of the light beam reflected from the reference mirror and measured at the image receiver 16 will change by 180 degrees with respect to the phase of the light reflected from the object 15 for every displacement of one quarter wavelength.
  • the light from the two beams reflected from the object 15 and the reference mirror 14 will interfere constructively and destructively as the mirror moves through one-quarter wavelength intervals. If the intensity of both the reference and object beams are equal, the intensity at the image receiver will be zero when the mirrors are positioned for maximum destructive interference. Very tiny displacements of one of the mirrors 14 or 15 can thus be measured.
  • FIGURE 2 is a schematic diagram of a prior art imaging interferometer much like the interferometer of FIGURE 1, except that the light source does not use a lens to collimate the light into a parallel beam 12. Instead, an off-axis paraboloid mirror 24 is used to reflect the light output 26 of an optical fiber 20 into a parallel beam of light 12. Mirror 24 is a section having a reflecting surface that is part of a parabola of revolution about the axis 22.
  • the end of the optical fiber 20 is placed on the axis 22 at or very near the focal point P of the paraboloid mirror, i.e., the point to which a parallel light beam parallel to light beam the axis 22 (which is the optical axis of the paraboloid mirror) coming in to and reflected from the mirror 24 would be focused.
  • the optical fiber 20 may incorporate a lens system (not shown) that appears to diverge the beam of light from the focal point P.
  • An optical system (shown symbolically as lens 29) is shown for imaging the surface of the object 15 on to the image receiver 16.
  • the optical system 29 and image receiver 15 can be integrated into a camera, where the image size of the object 15 on the image receiver may be much smaller than the size of the object 15.
  • the optical set up shown in FIGURE 2 is shown as a telecentric optical system, where diverging light rays 25 scattered from a point on the surface of the object 15 diverge until they pass through lens 29, then travel parallel to each other through an aperture 27, and are converged again to a point on the surface of the image receiver 16.
  • both prior art versions of the Michelson interferometer incorporate far too many cumbersome and expensive optical elements.
  • the prior art interferometers must include a reference mirror, a beam splitter, and an optical system or lens for collimating the light into the image receiver. Accordingly, there is a need in the art for interferometric system for investigating, imaging, and measuring the topography of the surfaces of large objects having lighter and/or less expensive optical elements. Moreover, there is a need in the art for an interferometric system having an easily variable ratio of object illumination intensity to reference beam intensity.
  • the present invention includes an interferometric imaging system that reduces or eliminates the need for any of the cumbersome and expensive optical elements associated with the prior art.
  • the system of the present invention includes a paraboloid mirror defining an axis and an illumination source adapted to radiate light from an illumination point at an off-axis portion of the paraboloid mirror, wherein the illumination point is disposed remotely from the axis of the paraboloid mirror.
  • the illumination point is disposed relative to the axis of the paraboloid mirror such that light diverges from the illumination point and proceeds to the paraboloid mirror.
  • the paraboloid mirror reflects light from the illumination source into a substantially parallel beam of light for illumination of an object.
  • the paraboloid mirror of the present invention functions as both a collimator of light from the illumination point as well as a collector of light reflected from the object under examination.
  • FIGURES 1 and 2 are schematic drawings of prior art interferometric systems.
  • FIGURE 3 is a schematic diagram of an interferometric system in accordance with a preferred embodiment of the present invention.
  • FIGURE 4 is a depiction of calculated distortions of divergent light at an object.
  • FIGURE 5 is a depiction of calculated distortions of divergent light at an image receiver.
  • FIGURE 6 is a schematic drawing of a variation of the preferred embodiment of the invention.
  • FIGURE 7 is a schematic drawing of another variation of the preferred embodiment of the invention.
  • FIGURE 8 is a schematic drawing of another variation of the preferred embodiment of the invention.
  • FIGURE 9 is a schematic drawing of another variation of the preferred embodiment.
  • a preferred embodiment of the present invention includes an mterferometric imaging system that reduces or eliminates the need for any of the cumbersome and expensive optical elements associated with the prior art.
  • the system of the preferred embodiment includes a paraboloid mirror defining an axis and an illumination source adapted to radiate light from an illumination point at an off-axis portion of the paraboloid mirror, wherein the illumination point is disposed remotely from the axis of the paraboloid mirror.
  • the illumination point is disposed relative to the axis of the paraboloid mirror such that light diverges from the illumination point and proceeds to the paraboloid mirror.
  • the paraboloid mirror reflects light from the illumination source into a substantially parallel beam of light for illumination of an object.
  • the paraboloid mirror of the present invention functions as both a collimator of light from the illumination point as well as a collector of light reflected from the object under examination.
  • the large reference mirror, the large beam splitter, and the lens described in the prior art are no longer needed.
  • Light 36 is radiated from an illumination source 30 and is shown diverging from an illumination point Pi disposed remotely from the focus point P of the paraboloid mirror 24 and thus remotely from an optical axis 22 of the paraboloid mirror 24. The light travels to the paraboloid mirror 24 and is reflected as a substantially parallel beam 37 that falls on the surface of an object 15.
  • a collimated light beam 37 is not parallel to the optical axis 22 of the paraboloid mirror.
  • Object light 38 is shown as a parallel beam reflecting from a surface of the object 15, where the surface is substantially perpendicular to the optical axis 22.
  • Object light 38 reflects again from the paraboloid mirror 24, and is then brought to a focus at a second point P 2 that is also disposed remotely from the focal point P and the optical axis 22 of the paraboloid mirror 24.
  • the system includes an aperture 31 that limits the light scattered from the object surface 15. Additionally, the system of preferred embodiment can include a beamsplitter 33 such that inbound light 39 is combined with light from a reference light source 32 prior to receipt by an image receiver 34.
  • the image receiver 34 captures the image of the surface of the object 15 and displays an interferometric phase image of the object surface.
  • a second variation of preferred embodiment of the system can also include a computer (not shown) connected to the image receiver 34.
  • the computer functions to capture and display phase images of the surface of the object 15 at different relative phases between the reference source 32 and the illumination source 3O and different wavelengths of light from the reference source 32 and the illumination source 30.
  • the computer further functions to construct synthetic phase images and holograms from the phase and wavelength data, functions that are known generally in the art of interferometry.
  • the illumination source 30 can be a laser light source, a diode laser light source, a light emitting diode (LED) light source, a gas discharge light source, an optical fiber laser, or an arc or incandescent light source.
  • a laser light source a diode laser light source, a light emitting diode (LED) light source, a gas discharge light source, an optical fiber laser, or an arc or incandescent light source.
  • the illumination source 30 can be optically coupled to an optical fiber.
  • the optical fiber is adapted to direct light from the illumination source 30 to the illumination point Pi.
  • the illumination source 30 can include for example a diode laser source, a light emitting diode, or an arc or incandescent light source that is connectable to the optical fiber.
  • the illumination source 30 can be a fixed frequency light source, a tunable frequency light source, or any other type of light source that is either fixed or tunable with respect to frequency.
  • the paraboloid mirror 24 In order to use the paraboloid mirror 24 as both a collimating optical element and as an image gathering optical element, there must be room for the incoming and outgoing focused beams to pass each other without obstruction or physical occlusion of either beam. Otherwise, a beam splitter would have to be used at or near the intersection point of the incoming or outgoing beams, and only a quarter of the possible object illumination light would reach the camera. Accordingly, in another variation of the system of the preferred embodiment, the beam splitter 33 can transmit most of the inbound light 39, while reflecting only a small part of a reference light from a reference source 32.
  • the point Pi is defined as apart from the focus P of the paraboloid mirror 24 when the distortion introduced in the beam incident on the object 15 is greater than one wave distortion across the object 15 as long as the paraboloid mirror 24 is paraboloid to within a small part of a wavelength.
  • the prior art system cited had the object illumination located so that the wavefront distortion at the object was less than one wave.
  • the point Pi is defined as being near to the point P when the illumination light 36 passes closely to but is not blocked by the aperture 31, and when the illumination source 30 and associated optics do not occlude or block inbound light 39 or obstruct optical elements necessary to combine the inbound beam 39 with the reference light from the reference source.
  • FIGURE 4 shows that the calculated distortions at the object are eighteen waves when the paraboloid mirror 24 is a thirty centimeters square mirror and where the optical axis 22 is forty eight millimeters from the edge of the mirror, the free space length from Pi to the object 15 surface is three thousand five hundred twenty two millimeters, and the point Pi is displaced from the focus point P by two millimeters.
  • the system can include a phase changing element adapted to change the phase of the light directed by the optical fiber.
  • a phase changing element 62 is connected to an optical fiber 60 that directs the illumination light 36 to the paraboloid mirror 24.
  • the optical fiber 60 is stretchable such that a mechanical, electronic, electro-mechanical or thermal device can alter and/ or extend the length of the optical fiber 60 thereby providing a corresponding change in the phase of the light directed by the optical fiber 60.
  • the phase changing element 62 can include for example a mechanical, electronic, electromechanical or thermal device that is adapted to alter and/or extend the length of the optical fiber 60 thereby providing a corresponding change in the phase of the light directed by the optical fiber 60.
  • the phase changing element 62 includes a piezoelectric tube 70, a portion of which is attached to the optical fiber 60 by an adhesive 74, epoxy, or other similar bonding agent. Another portion of the tube 70 is joined to a base 72 that is fixed with respect to the paraboloid mirror 24. In operation, the application of a voltage to the piezoelectric tube 70 lengthens piezoelectric tube 70, thereby stretching the optical fiber 60 and changing the relative phase of the illumination light 36 by a predetermined number of wavelengths.
  • the system further includes a second illumination source adapted to radiate light from an illumination point at an off-axis portion of the paraboloid mirror 24 such that the second illumination point is disposed remotely from the axis 22 of the paraboloid mirror 24.
  • the second illumination source can be a laser light source, a diode laser light source, a light emitting diode (LED) light source, a gas discharge light source, an optical fiber laser, or an arc or incandescent light source.
  • the second illumination source can be optically coupled to a second optical fiber.
  • the second optical fiber is adapted to direct light from the illumination source to the illumination point Pi.
  • the second illumination source can include for example a diode laser source, a light emitting diode, or an arc or incandescent light source that is connectable to the optical fiber.
  • the second illumination source can be a fixed frequency light source, a tunable frequency light source, or any other type of light source that is either fixed or tunable with respect to frequency.
  • FIGURE 8 An example of this variation of the system of the preferred embodiment is shown in FIGURE 8, in which a first optical fiber 80 and a second optical fiber 82 are disposed within a predetermined range of each other thereby producing the illumination light 36.
  • Each of the optical fibers 80, 82 can be placed so that the respective illumination points of the fibers are within a few hundred microns of each other.
  • the predetermined range between the first illumination point and the second illumination point is approximately 350 microns.
  • the predetermined range between the first illumination point and the second illumination point is less than 350 microns.
  • the predetermined range between the first illumination point and the second illumination point is between 100 and 350 microns.
  • each of the first optical fiber 80 and the second optical fiber 82 provides a diverging beam of light that diverges from different points Pm. Accordingly, each of the first optical fiber 80 and the second optical fiber 82 can have individual phase changing elements 62 attached thereto, or each fiber may be attached to a single phase changing element 62. As noted above, a phase changing element 62 is connected to an optical fiber 80, 82 that directs the illumination light 36 to the paraboloid mirror 24. In one alternative, the optical fiber 80, 82 is stretchable such that a mechanical, electronic, electro-mechanical or thermal device can alter and/ or extend the length of the optical fiber 80, 82 thereby providing a corresponding change in the phase of the light directed by the optical fiber 80, 82.
  • the phase changing element 62 can include for example a mechanical, electronic, electro-mechanical or thermal device that is adapted to alter and/or extend the length of the optical fiber 80, 82 thereby providing a corresponding change in the phase of the light directed by the optical fiber 80, 82.
  • the phase changing element 62 can include a piezoelectric tube 70 as shown in FIGURE 7, a portion of which is attached to the optical fiber 80, 82 by an adhesive 74, epoxy, or other similar bonding agent. Another portion of the tube 70 is joined to a base 72 that is fixed with respect to the paraboloid mirror 24. In operation, the application of a voltage to the piezoelectric tube 70 lengthens piezoelectric tube 70, thereby stretching the optical fiber 80, 82 and changing the relative phase of the illumination light 36 by a predetermined number of wavelengths.
  • the system further includes a fiber optical beam combiner adapted to combine light directed by the first optical fiber and the second optical fiber.
  • the fiber optical beam combiner 90 is adapted to combine light directed by multiple optical fibers 92, 94, and 96, wherein each of the optical fibers 92, 94, 96 direct light from distinct illumination sources 93, 95, and 97.
  • Each of the multiple optical fibers 92, 94, 96 can be connected to a phase changing element as described above.
  • a phase changing element can be connected to a separate optical fiber 60 that is adapted to direct a consolidated beam of light subsequent to the fiber optical beam combiner 90.
  • Each of the illumination sources 93, 95, 97 can include for example a laser light source, a diode laser light source, a light emitting diode (LED) light source, a gas discharge light source, an optical fiber laser, an arc or incandescent light source, or any combination or permutation thereof.
  • a laser light source for example a laser light source, a diode laser light source, a light emitting diode (LED) light source, a gas discharge light source, an optical fiber laser, an arc or incandescent light source, or any combination or permutation thereof.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

Système d'imagerie interférométrique à miroir paraboloïde définissant un axe et à source d'éclairage rayonnant la lumière depuis un point d'éclairage au niveau d'une partie hors axe du miroir, sachant que le point d'éclairage est distant par rapport à l'axe du miroir considéré. Ce point est placé par rapport à l'axe dudit miroir de sorte que la lumière diverge du point en question et se dirige vers le miroir, lequel réfléchit la lumière provenant de la source en un faisceau de lumière sensiblement parallèle pour l'éclairage d'un objet. Le miroir décrit tient lieu à la fois de collimateur de lumière depuis le point d'éclairage et de collecteur de lumière réfléchie depuis l'objet examiné.
PCT/US2006/047520 2005-12-12 2006-12-12 Interferometre paraboloide hors axe a eclairage hors axe WO2007070565A2 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US11/301,320 2005-12-12
US11/301,320 US7440114B2 (en) 2005-12-12 2005-12-12 Off-axis paraboloid interferometric mirror with off focus illumination
US11/299,548 US20070133008A1 (en) 2005-12-12 2005-12-12 Optical fiber delivered reference beam for interferometric imaging
US11/299,548 2005-12-12

Publications (2)

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WO2007070565A2 true WO2007070565A2 (fr) 2007-06-21
WO2007070565A3 WO2007070565A3 (fr) 2009-09-24

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PCT/US2006/047521 WO2007070566A2 (fr) 2005-12-12 2006-12-12 Faisceau de reference achemine par fibre optique pour imagerie interferometrique
PCT/US2006/047520 WO2007070565A2 (fr) 2005-12-12 2006-12-12 Interferometre paraboloide hors axe a eclairage hors axe

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PCT/US2006/047521 WO2007070566A2 (fr) 2005-12-12 2006-12-12 Faisceau de reference achemine par fibre optique pour imagerie interferometrique

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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4653855A (en) * 1984-10-09 1987-03-31 Quantum Diagnostics Ltd. Apparatus and process for object analysis by perturbation of interference fringes
US4814774A (en) * 1986-09-05 1989-03-21 Herczfeld Peter R Optically controlled phased array system and method
US5071251A (en) * 1989-06-12 1991-12-10 California Institute Of Technology Wavelength independent interferometer
US6327038B1 (en) * 1999-09-21 2001-12-04 Ut-Battelle, Llc Linear and angular retroreflecting interferometric alignment target
US6507405B1 (en) * 1999-05-17 2003-01-14 Ultratech Stepper, Inc. Fiber-optic interferometer employing low-coherence-length light for precisely measuring absolute distance and tilt
US20030112442A1 (en) * 2001-08-28 2003-06-19 Baney Douglas M. Optical analyzer and method for reducing relative intensity noise in interferometric optical measurements using a continuously tunable laser
US20040179204A1 (en) * 2003-03-10 2004-09-16 Fuji Photo Optical Co., Ltd. Speckle interferometer apparatus
US6806965B2 (en) * 2001-05-22 2004-10-19 Zygo Corporation Wavefront and intensity analyzer for collimated beams
US20050270543A1 (en) * 2004-06-07 2005-12-08 Fujinon Corporation Wavefront-measuring interferometer apparatus, and light beam measurement apparatus and method thereof

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5548403A (en) * 1994-11-28 1996-08-20 The Regents Of The University Of California Phase shifting diffraction interferometer
US6654119B1 (en) * 1999-04-21 2003-11-25 Chromagen, Inc. Scanning spectrophotometer for high throughput fluroescence detection

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4653855A (en) * 1984-10-09 1987-03-31 Quantum Diagnostics Ltd. Apparatus and process for object analysis by perturbation of interference fringes
US4814774A (en) * 1986-09-05 1989-03-21 Herczfeld Peter R Optically controlled phased array system and method
US5071251A (en) * 1989-06-12 1991-12-10 California Institute Of Technology Wavelength independent interferometer
US6507405B1 (en) * 1999-05-17 2003-01-14 Ultratech Stepper, Inc. Fiber-optic interferometer employing low-coherence-length light for precisely measuring absolute distance and tilt
US6327038B1 (en) * 1999-09-21 2001-12-04 Ut-Battelle, Llc Linear and angular retroreflecting interferometric alignment target
US6806965B2 (en) * 2001-05-22 2004-10-19 Zygo Corporation Wavefront and intensity analyzer for collimated beams
US20030112442A1 (en) * 2001-08-28 2003-06-19 Baney Douglas M. Optical analyzer and method for reducing relative intensity noise in interferometric optical measurements using a continuously tunable laser
US20040179204A1 (en) * 2003-03-10 2004-09-16 Fuji Photo Optical Co., Ltd. Speckle interferometer apparatus
US20050270543A1 (en) * 2004-06-07 2005-12-08 Fujinon Corporation Wavefront-measuring interferometer apparatus, and light beam measurement apparatus and method thereof

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WO2007070565A3 (fr) 2009-09-24
WO2007070566A3 (fr) 2009-01-08
WO2007070566A2 (fr) 2007-06-21

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