Abstract: A method of producing an optoelectronic component includes providing a cavity; introducing a liquid matrix material with phosphor particles distributed therein into the cavity; introducing a semiconductor chip into the matrix material; sedimenting the phosphor particles in the matrix material; and curing the matrix material, wherein a conversion layer including phosphor particles is produced, said conversion layer being arranged on the semiconductor chip.

Abstract: Method and system of interferometrically measuring, in reflection, a non-spherical surface with two diffracted beams (of different diffraction orders) formed by a diffractive element positioned transversely to the axis of a common-path interferometer. The first diffracted beam substantially maintains the wavefront of a beam incident onto the diffractive element, while the second diffracted beam has a wavefront profile corresponding to the profile of the measured surface. The first diffracted beam may be reflected by the surface in a cat's eye configuration, while the second diffracted beam is reflected by the surface in a confocal configuration. The surface being measured can be modified to substantially balance radiant powers of the first and second diffracted beams upon reflection off the surface.

Abstract: An interferometer includes a light source and a beam splitter, via which the beam of rays emitted by the light source is split into a measurement beam and a reference beam. The measurement beam propagates in a measuring arm extending in a first direction between the beam splitter and a measuring reflector. The measuring reflector brings about an offset perpendicular to the direction of incidence between the measurement beam falling on it and the measurement beam reflected back by it. In a reference arm extending in a second direction, the reference beam propagates between the beam splitter and a reference reflector. In addition, the interferometer has a detector system, to which the superposed and recombined measurement beam and reference beam are able to be supplied, and via which a distance-dependent interference signal with respect to the position of the measuring reflector is able to be generated.

Abstract: Provided is an imaging apparatus for acquiring a tomographic image of an object to be inspected based on light obtained by combining return light from the object illuminated with measuring light and reference light corresponding to the measuring light, the imaging apparatus including: a reference-light amount changing unit provided in an optical path of the reference light, for changing a reference-light amount of the reference light; and a control unit for controlling the reference-light amount changing means so as to control the reference-light amount within a predetermined range and an image quality of the tomographic image within a predetermined image-quality evaluation range.

Abstract: An object of the present invention is to provide an optical inspection apparatus that suppresses an influence of quantum noise and obtains superior defect detection performance even when an amount of light is small and a method thereof. In order to resolve the above problem, the present invention provides an optical inspection apparatus that includes a light source which radiates light to a sample; a light interference device which causes target light transmitted, scattered, or reflected from the sample and reference light to interfere with each other, such that strength of light after the interference becomes lower than strength of the target light; a photon counter which measures a photon number of the light after the interference by the light interference device; and a defect identifier which identifies the presence or absence of a defect, on the basis of a detected photon number obtained by the photon counter.

Abstract: The scanning speed of a sample in Doppler OCT, etc., is increased to enable quick measurement of blood flow rate, blood flow volume, etc.

Abstract: An apparatus for detecting a 3D structure of an object. The apparatus has first and second laser emitters which generate laser radiation having first and second wavelengths, respectively, the first wavelength being different from the second wavelength. Optical devices are disclosed, including a beam splitter, which splits the laser radiation of the laser emitters in each case into a reference radiation and an illuminating radiation. The illuminating radiation impinges upon the object to be measured, is reflected by the object as object radiation and interferes with the reference radiation. A detector receives the interference patterns. The laser emitters are located such that the illuminating radiation of the first and second laser emitters impinge upon the object at different angles of incidence. Also discussed is a measuring device which measures the two wavelengths of the laser radiation of the laser emitters and influences the recording of the interference patterns.

Abstract: Provided herein is a TSV measuring interferometer that uses a variable field stop that adjusts such that a light is focused at an inlet and at a bottom surface of a TSV when measuring a diameter and depth of the TSV, thereby reducing a measurement time and result data, the interferometer also using a telecentric lens that adjusts the light injected into the TSV to be a straight line, so as to obtain a sufficient amount of light reaching the bottom surface to improve the accuracy of measurement even in a TSV having a large aspect ratio.

Abstract: A method for determining information about a test object includes combining two or more scanning interference signals to form a synthetic interference signal; analyzing the synthetic interference signal to determine information about the test object; and outputting the information about the test object. Each of the two or more scanning interference signals correspond to interference between test light and reference light as an optical path length difference between the test and reference light is scanned, wherein the test and reference light are derived from a common source. The test light scatters from the test object over a range of angles and each of the two or more scanning interferometry signals corresponds to a different scattering angle or polarization state of the test light.

Abstract: A method for determining roughness data and/or topography data of surfaces in material microscopy, particularly from flat samples, based on a shearing polarization interferometrical sequence with a microscopic “TIC” module (“Total Interference Contrast Module”) of a microscope, wherein the method can be carried out both polychromatically and monochromatically. At least two tilted wave fronts are generated, which after reflection or transmission on a sample generate two images of said sample in the form of fringe patterns, said images being offset relative to one another and interfering with one another, from which roughness values and height topographies of the surface of the sample are determined by application of image evaluation.

Abstract: A system and method of measuring feature depth using a common path auto-correlation low coherence interferometer including a light source having an output directed toward a first beam splitter, the first beam splitter directing at least a portion of a light beam from the light source toward a sample having two reflective interfaces including a top surface reflective interface and a feature bottom reflective interface. The first beam splitter can also pass toward a second beam splitter each of a reference light beam reflected from the top surface interface and a measurement light beam reflected from the feature bottom reflective interface. The second beam splitter directs the reference light beam to a first mirror and the measurement light beam to a second mirror and combines a reflected measurement light beam from the second mirror and a reflected reference light beam from the first mirror to form an interference pattern.

Abstract: A polarization imaging apparatus includes a laser light source and an image pickup element. Object light and reference light each include a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction. The image pickup element simultaneously captures an image of an interference pattern including (i) a first interference figure, (ii) a second interference figure, (iii) a third interference figure, and (iv) a fourth interference figure. The polarization imaging apparatus includes a reconstructing section generating respective reconstructed images of the object in regard to the first and second polarized-light components, from the first to fourth interference figures, and a polarized-light-image-calculating section obtaining polarized-light images from the reconstructed images.

Abstract: The time delay (and therefore the OPD) between object and reference beams in an interferometer is manipulated by changing the spectral properties of the source. The spectral distribution is tuned to produce a modulation peak at a value of OPD equal to the optical distance between the object and reference arms of a Fizeau interferometer, thereby enabling the use of its common-axis configuration to carry out white-light measurements free of coherence noise. Unwanted interferences from other reflections in the optical path are also removed by illuminating the object with appropriate spectral characteristics. OPD scanning is implemented without mechanical means by altering the source spectrum over time so as to shift the peak location by a predetermined scanning step between acquisition frames. The invention and its advantages are applicable to optical coherence tomography as well as conventional white light interferometry.

Abstract: An embodiment of the present invention realizes an interference measurement apparatus which can obtain an interference image to be used for obtaining three-dimensional information of a subject which dynamically changes.

Abstract: The present invention provides a measurement apparatus which measures a shape of a test object, including a detection unit configured to detect interference light between reference light from a reference surface and test light from the test object, thereby obtaining an interference image, and a processing unit configured to perform processing of obtaining the shape of the test object based on the interference image obtained by the detection unit, wherein in a measurement mode in which the interference image is obtained under a measurement condition that the optical path length difference measurable range is a second range smaller than a first range, the processing unit obtains a second shape of the test object by using data of an obtained first shape, and the interference image obtained by the detection unit in the measurement mode.

Abstract: A color chart having a plurality of mirror-image color blocks arranged in a matrix, with each color block a mirror image of an adjacent color block, each color block having rows and columns of color patches, wherein the concentration of a first color of the multiple colors changes unidirectionally across color patches in any given row of a color block, the concentration of a second color of the multiple colors changes unidirectionally across color patches in any given column of a color block, and the concentration of a third color of the multiple colors remains unchanged across all the plurality of color patches within a color block and differs only between color blocks.

Abstract: An imaging apparatus includes a light source; a first beam splitter for reflecting a projection beam emitted by the light source; an objective lens unit including a reflection reference surface for reproducing the projection beam into a measurement beam projected onto an object to generate a first reflection beam and a reference beam projected onto the reflection reference surface to generate a second reflection beam mixing with the first reflection beam and passing through the first splitter and forming an operating beam; a second beam splitter for modulating the operating beam into first and second sub-beams; a monochrome image detection device for passage of the first sub-beam to obtain an interferometric image with monochrome from a first interference region; and an image detection device for permitting passage of the second sub-beam in order to obtain a non-interferometric image from a second interference region.

Abstract: An aberration measurement system includes an interferometer that includes a polarization adjuster configured to adjust a polarization plane of coherent light, and a phase shifter configured to shift a phase of reference light. The aberration measurement system further includes a signal processing unit configured to obtain a nonpolarization aberration of the test object, and coefficients a=sin ? cos 2?, b=sin ? sin 2?, and c=cos ? for a retardation amount 2? and a principal axis direction ? of a polarization aberration of the test object, based on data of a plurality of interference pattern images which provide at least three complex visibilities obtained from the interferometer after a polarization adjuster adjusts the polarization plane of the coherent light, and to determine signs of the coefficients a, b, and c based on the nonpolarization aberration.

Abstract: A polarization sensitive spectral interferometer apparatus and method for analyzing a sample by optical energy reflected from the sample. The polarization sensitive spectral interferometer apparatus and method determines polarization properties of the sample by optical energy reflected from the sample.

Abstract: The invention relates to an apparatus and a method for determining a height map of a surface of an object. The apparatus can include positioning means for the object, a light source, an optical detector for converting the received light into electrical signals, first optics for directing light from the light source to the surface and for directing the light from the surface to the optical detector, a beam splitter located between the first optics and the surface, a reference mirror, second optics located between the beam splitter an the mirror for directing the light from the beam splitter to the mirror and from the mirror to the beam splitter, scanning means, processing means that converts the signal from the optical detector into a height map. The beam splitter can be a polarizing beam splitter. A controllable polarization controller can be located between the light source and the first optics.

Abstract: The time delay (and therefore the OPD) between object and reference beams in an interferometer is manipulated by changing the spectral properties of the source. The spectral distribution is tuned to produce a modulation peak at a value of OPD equal to the optical distance between the object and reference arms of a Fizeau interferometer, thereby enabling the use of its common-axis configuration to carry out white-light measurements free of coherence noise. Unwanted interferences from other reflections in the optical path are also removed by illuminating the object with appropriate spectral characteristics. OPD scanning is implemented without mechanical means by altering the source spectrum over time so as to shift the peak location by a predetermined scanning step between acquisition frames. Finally, the spectrum is controlled on a pixel-by-pixel basis to create a virtual surface that matches the profile of a particular sample surface.

Abstract: A detection apparatus and an imaging apparatus are capable of accurately conducting non-destructive observation of a target by using an incoherent electromagnetic wave. The detection apparatus has a generating section, a first coupler section, a delaying section, a second coupler section and a signal processing section. The generating section 101 includes a coherent electromagnetic wave source 102 and a diffusing section 103 for generating a pseudoincoherent electromagnetic wave by changing a propagation state of the coherent electromagnetic wave in accordance with a code pattern. The incoherent electromagnetic wave is split into first and second waves and the first wave is affected by the target of observation while the second wave is delayed by the delaying section. The first and second waves are then coupled to produce a coupled wave having a correlation signal of them and the signal is utilized to acquire information on the inside of the target of observation.

Abstract: An interferometer that measures a shape of a surface of an inspection object includes an interference optical system that splits light from a light source into inspection light and reference light and causes the inspection light reflected by the surface of the inspection object and the reference light to interfere with each other, and a photoelectric conversion element that detects interference fringes produced by interference between the inspection light and the reference light. The interference optical system includes a first optical element that transmits and reflects the inspection light, a second optical element that reflects the inspection light, and a moving unit configured to move the second optical element. The inspection light passes through the first optical element, is reflected by the second optical element, is reflected by the first optical element, and is then incident on the surface of the inspection object.

Abstract: The present invention provides a measurement apparatus which measures a wavefront of light traveling from a member to be measured, the apparatus including a first reference surface, a second reference surface configured to function as a reference surface for the first reference surface, an optical system configured to form a first interference pattern of light traveling from the member to be measured and light traveling from the first reference surface, and a second interference pattern of light traveling from the first reference surface and light traveling from the second reference surface, a detection unit configured to detect the first interference pattern and the second interference pattern, respectively, and a calculation unit configured to calculate a wavefront of light traveling from the member to be measured based on the first interference pattern and the second interference pattern detected by the detection unit.

Abstract: An orthogonal-polarization Mirau interferometric system is provided, wherein a narrow-band or broad-band incident light is split into a reference light and an inspection light with the polarizations thereof being orthogonal to each other by using a beam-splitting module, while projecting the inspection light on a measured object to form an object light, and then the object light and the reference light are combined to form a combined light, and thereafter, an analyzer is utilized to modulate the polarizations and the intensities of the two lights for making the two lights interfere with each other and thus create an interference pattern. The polarization of the object light and that of the reference light can be adjusted by using an analyzer to become orthogonal to each other, and the intensities of the object light and the reference light can be adjusted to about the same for producing an interference pattern with high contrast.

Abstract: Methods, devices and systems of an optical sensor for spatially smart 3-D object measurements using variable focal length lenses to target both specular and diffuse objects by matching transverse dimensions of the sampling optical beam to the transverse size of the flat target for given axial target distance for instantaneous spatial mapping of flat target, zone. The sensor allows volumetric data compressed remote sensing of object transverse dimensions including cross-sectional size, motion transverse displacement, inter-objects transverse gap distance, 3-D animation data acquisition, laser-based 3-D machining, and 3-D inspection and testing. An embodiment provides a 2-D optical display using 2-D laser scanning and 3-D beamforming optics engaged with sensor optics to measure distance of display screen from the laser source and scanning optics by adjusting its focus to produce the smallest focused beam spot on the display screen.

Abstract: A method and a device for dynamic measurement of the radial deformation of a bearing ring (12) of a rolling bearing (10) for a rotating element (16), a glass fiber segment (22) of a fiber optic sensor (24) that is fixed in or to the periphery of the bearing ring, a light signal which has been generated by the light source (30) being injected into the glass fiber segment, and the light signal passing through the glass fiber segment being detected by a detector (34), the longitudinal deformation of the glass fiber segment being determined from the change of at least one parameter of the light signal, when the light signal passes through the glass fiber segment, in order to determine the corresponding radial deformation of the bearing ring.

Abstract: An optical measuring apparatus may include a light source, linear polarizer, polarized beam splitter, quarter wave plate, objective lens, and/or light receiver. The polarized beam splitter may be configured to transmit linearly polarized light from the linear polarizer to any one of a first and second optical path. The quarter wave plate may be configured to circularly polarize light transmitted through the first optical path from the polarized beam splitter and transmit the circularly polarized light to an object to be measured, and the quarter wave plate may be configured to linearly polarize the circularly polarized light reflected from the object to be measured and transmit the linearly polarized reflected light to the second optical path of the polarized beam splitter. The objective lens may be configured to generate light having different wavelengths by generating chromatic aberration in the circularly polarized light from the quarter wave plate.

Abstract: The present invention relates to a vibration-insensitive interferometer using a high-speed camera and a continuous phase scanning method. The interferometer measures a measurement target by completely isolating influences of externally occurring vibrations from a frequency domain. The interferometer includes a light source unit for emitting light. A light transmission unit radiates the light emitted from the light source unit to the measurement target, splits light reflected from the measurement target into reference light and measurement light, and allows the reference light and the measurement light to interfere with each other, thus generating an interference fringe. A continuous phase scanning unit for radiates the reference light split by the light transmission unit through continuous phase scanning.

Abstract: A system and method for analyzing the dynamics of fluid layers on contact lenses utilizes phase shifting interferometry to quickly and accurately model the time-evolution of the fluid layers. The system and method are utilized for in vitro studies.

Abstract: A source module (12) generates mutually orthogonally polarized beams of light as emanating from two spatially separated point sources (Sv, Sw) for use in a phase shifting interferometer.

Abstract: The conventional two plates with beamsplitter of the Mirau interferometer are replaced with two achromatic ?/4 retarders. The upper surface of the second retarder is coated with a 50 percent reflecting film, so that it also functions as a beamsplitter. The objective is illuminated with a linearly polarized beam. As a result of this arrangement, the test and reference beam emerging from the Mirau interferometer are orthogonally polarized beams suitable for achromatic phase shifting, thereby facilitating the use of the Mirau interferometer for monochromatic to broadband phase-shifting interference microscopy. Alternatively, it can be used for equalization of beams intensity by placing a rotatable polarizer at the exit of the objective.

Abstract: An embodiment of the present invention realizes an interference measurement apparatus which can obtain an interference image to be used for obtaining three-dimensional information of a subject which dynamically changes.

Abstract: Systems and methods are provided for multi-function coherent imaging comprising directing a first coherent radiation beam and a second coherent radiation beam towards a detector, where the second coherent radiation beam is spatially offset, angularly offset, or spatially and angularly offset from the first coherent radiation beam. A portion of the first coherent radiation beam and a portion of the second coherent radiation beam may be combined to form a composite beam. An object may be radiated with the composite beam. A first intensity pattern may be formed by interfering with return radiation from the radiated object with the first coherent radiation beam and a second intensity pattern is formed with the return radiation from the radiated object and the second coherent radiation beam. A detector may simultaneously record a superposition of the first intensity pattern and the second intensity pattern.

Abstract: An optical image measuring device includes: an optical system that generates and detects interference light; an image forming part that forms a tomographic image based on the detection; an alignment part that performs alignment of the optical system with respect to an object; a focusing part that focuses the optical system with respect to the region of interest; a determining part that determines the suitability of the position of the optical system by the alignment part, the suitability of the focus state by the focusing part, and the suitability of the position of the tomographic image in a frame; a control part that, when it is determined that all of the positions of the optical system, position of focus state and the position in said frame are appropriate, controls the optical system and the image forming part, making it possible to obtain the tomographic image of the region of interest.

Abstract: Provided is an optical image measuring apparatus capable of obtaining a high-accuracy image without being influenced by a movement of an object to be measured. Flash light is emitted from a xenon lamp (2) and converted into broad band light by an optical filter (2A). A polarization characteristic of the flash light is converted into linear polarization by a polarizing plate (3). Then, the flash light is divided into signal light (S) and reference light (R) by a half mirror (6). A polarization characteristic of the reference light (R) is converted into circular polarization by a wavelength plate (7). The signal light (S) and the reference light (R) are superimposed on each other by the half mirror (6) to produce interference light (L). A CCD (23) detects interference light having the same characteristic as that of the produced interference light (L).

Abstract: A source module (12) generates mutually orthogonally polarized beams of light as emanating from two spatially separated point sources (Sv, Sw) for use in a phase shifting interferometer.

Abstract: In one aspect, the disclosure features methods that include using a microscope to direct light to a test object and to direct the light reflected from the test object to a detector, where the light includes components having orthogonal polarization states, varying an optical path length difference (OPD) between the components of the light, acquiring an interference signal from the detector while varying the OPD between the components, and determining information about the test object based on the acquired interference signal.

Abstract: An aberration measurement system includes an interferometer that includes a polarization adjuster configured to adjust a polarization plane of coherent light, and a phase shifter configured to shift a phase of reference light. The aberration measurement system further includes a signal processing unit configured to obtain a nonpolarization aberration of the test object, and coefficients a=sin ? cos 2?, b=sin ? sin 2?, and c=cos ? for a retardation amount 2? and a principal axis direction ? of a polarization aberration of the test object, based on data of a plurality of interference pattern images which provide at least three complex visibilities obtained from the interferometer after a polarization adjuster adjusts the polarization plane of the coherent light, and to determine signs of the coefficients a, b, and c based on the nonpolarization aberration.

Abstract: The invention relates to an apparatus and a method for determining a height map of a surface of an object. The apparatus can include positioning means for the object, a light source, an optical detector for converting the received light into electrical signals, first optics for directing light from the light source to the surface and for directing the light from the surface to the optical detector, a beam splitter located between the first optics and the surface, a reference mirror, second optics located between the beam splitter an the mirror for directing the light from the beam splitter to the mirror and from the mirror to the beam splitter, scanning means, processing means that converts the signal from the optical detector into a height map. The beam splitter can be a polarizing beam splitter. A controllable polarization controller can be located between the light source and the first optics.

Abstract: Methods for displaying anisotropic properties of an object. The object is illuminated with a first test beam characterized by a first polarization that, after traversing the object, is combined with a reference beam. The combined light of the first transmitted test beam and the reference beam is analyzed by a first pair of polarization analyzers, and interference created between the first transmitted test beam and the reference beam as analyzed by the first pair of analyzers is detected to derive intensity, phase and polarization of the first transmitted test beam. The same is then done with a second test beam that has a polarization with a component orthogonal to the first polarization. Based on the two analyzed beams, complex elements of a Jones matrix associated with the object in a local coordinate system are determined and a plurality of tangible images are displayed that characterize the object based on the complex elements of the Jones matrix.

Abstract: Methods, fourier domain optical coherence tomography (FDOCT) interferometers and computer program products are provided for removing undesired artifacts in FDOCT systems using continuous phase modulation. A variable phase delay is introduced between a reference arm and a sample arm of an FDOCT interferometer using continuous phase modulation. Two or more spectral interferograms having different phase delay integration times are generated. The spectral interferograms are combined using signal processing to remove the undesired artifacts. Systems and methods for switching between stepped and continuous phase shifting Fourier domain optical coherence tomography (FDOCT) and polarization-sensitive optical coherence tomography (PSOCT) are also provided herein.

Abstract: A method for approximating an influence of an optical system on the state of polarization of optical radiation comprises the steps of providing incoming optical radiation for the optical system in several incoming states of polarization, including at least one incoming state having circularly polarized radiation components; directing the incoming optical radiation onto the optical system; measuring at least one characteristic, including a phase distribution, of a resulting outgoing optical radiation emerging from the optical system with respect to each of the incoming states of polarization; and approximating the influence of the optical system on the state of polarization of optical radiation by evaluating the measured characteristics of the outgoing optical radiation.

Abstract: An optical profiler for an ultra-smooth surface, such as a magnetic recording disk, provides for a normally incident beam deflection against the target surface to be profiled. A linearly polarized laser light of a first polarization is focused on the target surface in a normally incident direction. The beam is reflected back along its original path from the focal point. Optics are provided that change the polarization of the reflected beam to a second polarization. A reflected beam, with a second polarization, is directed onto a position sensitive detector for evaluation.

Abstract: A phase-difference sensor measures the spatially resolved difference in phase between orthogonally polarized reference and test wavefronts. The sensor is constructed as a linear-carrier phase-mask aligned to and imaged on a linear-carrier detector array. Mireau and Fizeau polarization interferometric objectives are implemented with a thin conductive wire grid optically coupled to the objective beam splitter.

Abstract: A measurement method of measuring a wavefront aberration of an optical system to be measured, comprising a first measurement step of measuring wavefronts of the optical system to be measured with respect to linearly polarized light beams along at least three different azimuths, a first calculation step of calculating a wavefront of the optical system to be measured with respect to non-polarized light and a birefringent characteristic of the optical system to be measured, based on the wavefronts of the optical system to be measured, which are measured in the first measurement step, and a second calculation step of calculating a wavefront of the optical system to be measured with respect to arbitrary polarized light, based on the wavefront and the birefringent characteristic of the optical system to be measured, which are calculated in the first calculation step.

Abstract: A method and device for optical determination of physical properties of features, not much larger than the optical wavelength used, on a test sample are described. A beam is split into reference and illuminating beams having known polarization. The test sample is exposed to the illuminating beam and recombined to form an image. The image is detected using at least one sensor, which may be cameras. A point-to-point map of polarization, phase and power is extracted from data representing the image. Optionally, the sensor may be a camera. The sensor may detect at least three optical parameters, such as a Stokes vector, a Jones vector, a Jones matrix, a Mueller matrix or a coherency matrix.

Abstract: A method for inspecting a transparent substrate provides an index-matching fluid between an index-matched optical coupler and a surface of the transparent substrate. The method repeats, at two or more positions along the surface of the transparent substrate, steps of illuminating an inspection volume within the transparent substrate by directing a ribbon of light through the optical coupler and into the transparent substrate and detecting scattered light from the inspection volume at a detector that is optically conjugate with the inspection volume.

Abstract: A phase-difference sensor measures the spatially resolved difference in phase between orthogonally polarized reference and test wavefronts. The sensor is constructed as a linear-carrier phase-mask aligned to and imaged on a linear-carrier detector array. Each adjacent element of the phase-mask measures a predetermined relative phase shift between the orthogonally polarized reference and test beams. Thus, multiple phase-shifted interferograms can be synthesized at the same time by combining pixels with identical phase-shifts. The multiple phase-shifted interferograms can be combined to calculate standard parameters such as modulation index or average phase step. Any configuration of interferometer that produces orthogonally polarized reference and object beams may be combined with the phase-difference sensor of the invention to provide single-shot, simultaneous phase-shifting measurements.

Abstract: In an optical tomography system, a polarization changing system which converts linearly polarized light too non-linearly polarized light is provided in at least one of a light source unit, an optical path from the light source unit to a light dividing system, the optical path of the measuring light from the light dividing system to an object, the optical path of the reflected light from the object to the combining system and the optical path of the reference light from the light dividing system to the combining system. The polarization changing system is, for instance, a polarization-preserving optical fiber which is disposed so that the direction of polarization of the linearly polarized light and the direction of axis of polarization of the linearly polarized light differ from each other.