With Birefringent Element Patents (Class 356/365)
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Patent number: 6636309Abstract: Application of selected wavelength range, oblique angle of incidence, reflection mode, spectroscopic ellipsometry DELTA data to monitor and/or control fabrication of multiple layer High/Low Refractive Index Narrow Bandpass Optical Filters, either alone or in combination with transmissive or reflective non-ellipsometric data obtained at an essentially normal angle of incidence.Type: GrantFiled: July 27, 2001Date of Patent: October 21, 2003Assignee: J.A. Woollam Co.Inventors: Blaine D. Johs, Jeffrey S. Hale
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Patent number: 6633053Abstract: At least one qubit in a quantum computing device is created. At least one photon is placed into a superposition of quantum states. The quantum states each have an associated probability amplitude. The quantum states each are associated with a mode from a group of orthogonal modes. The probability amplitudes associated with the quantum states of the at least one photon are temporally separated thereby forming at least one qubit, the alternative values of which are thus temporally identifiable.Type: GrantFiled: April 3, 2000Date of Patent: October 14, 2003Inventor: Gregg Scott Jaeger
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Publication number: 20030184749Abstract: A birefringence measurement apparatus includes a measurement part for measuring a birefringence azimuth and a birefringence amount of an object to first and second light having different wavelengths from each other, and a determination part for calculating at least one of a birefringence azimuth and a birefringence amount to third light different in wavelength from the first and second light based on the birefringence azimuth and birefringence amount of the object to the first and second light.Type: ApplicationFiled: March 19, 2003Publication date: October 2, 2003Inventor: Shuichi Yabu
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Patent number: 6628388Abstract: A transparent flow channel fluidly communicates a fluid source and a collection reservoir. A light beam passes through a first polarizer having a first plane of polarization. The flow channel is orthogonal to the light beam. The light beam passes through a fluid sample as it flows through the flow channel. The light beam is then filtered through a second polarizer having a second plane of polarization rotated 90° from the first plane of polarization. The birefringence of certain crystalline materials present in the fluid sample rotates the plane of polarization of the light beam. The presence of these microcrystals thus causes a component of the beam to pass through the second polarizer and impinge an electronic photo-detector located in the path of the beam. The photo-detector signals the presence of the microcrystals by generating voltage pulses. A display device visually presents the quantitative results of the assay.Type: GrantFiled: March 21, 2001Date of Patent: September 30, 2003Assignee: The Regents of the University of CaliforniaInventors: Chris Darrow, Andrew Mirhej, Tino Seger
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Patent number: 6624889Abstract: An optical channel monitor (OCM) or filter for analyzing an incident light carrying a number of narrow band signal channels such as WDM or DWDM channels. The OCM or filter use an acousto-optic tunable filter to receive and refract from an incident light a refracted light such that the refracted light contains a test channel with a center frequency &ngr;0. A first birefringent element is provided for filtering from the refracted light a first polarized light and a second polarized light orthogonal to the first polarized light. The transmission curves are engineered such that the transmissions of the first and second polarized light are substantially equal at the center frequency &ngr;0 of the test channel. The OCM or filter has a second birefringent element for filtering from the first polarized light a first polarized portion and a second polarized portion.Type: GrantFiled: April 29, 2002Date of Patent: September 23, 2003Assignee: Oplink Communications, Inc.Inventor: Shifang Li
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Publication number: 20030156287Abstract: An optical wavelength analyser including: an entrance slit (4) for receiving a light beam (3) including signals with various wavelengths and passings the beam at least partly; a diffractor (6, 7, 9) for receiving the passed beam and diffracting the signals dependent on their wavelength; a detector (8) including adjacent detector elements (32, 33, 35, 36, 38, 39) for receiving the diffracted signals and generating their output signals; a processor (21) for determining the wavelengths from the output signals, in which the received light beam has a spatially uniform intensity; the diffractor diffracts each signal on a different detector element subset, consisting of at least a first element (32, 33, 35, 36, 38, 39) for receiving at least a first signal with a first signal level; the processor determines each signal's wavelength dependent on the first signal level and a calibration value.Type: ApplicationFiled: February 27, 2003Publication date: August 21, 2003Inventor: Lun Kai Cheng
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Patent number: 6583931Abstract: In a projection optical system having at least two silica glass optical members, a birefringence value is measured at each of points in a plane normal to the optical axis with the center at an intersection of each optical member with the optical axis, a distribution of signed birefringence values in each optical member is obtained by assigning a positive sign to each birefringence value when a direction of the fast axis thereof is a radial direction to the intersection with the optical axis and assigning a negative sign to each birefringence value when the direction of the fast axis thereof is normal to the radial direction, and the optical members are combined with each other so as to satisfy such a placement condition that a signed birefringence characteristic value of the entire projection optical system calculated based on the distributions of signed birefringence values is between −0.5 and +0.5 nm/cm both inclusive.Type: GrantFiled: December 27, 2001Date of Patent: June 24, 2003Assignee: Nikon CorporationInventors: Hiroyuki Hiraiwa, Issey Tanaka
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Patent number: 6567167Abstract: A real-time optical compensating apparatus reduces the PMD in an optical fiber by determining the principal states of polarization of the optical fiber and delaying one principal state of polarization with respect to the other.Type: GrantFiled: February 16, 2000Date of Patent: May 20, 2003Assignee: Massachusetts Institute of TechnologyInventors: Patrick C. Chou, Hermann A. Haus
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Publication number: 20030030805Abstract: A practical system and method for measuring waveplate retardation. The system employs a photoelastic modulator in an optical setup and provides high sensitivity. The analysis is particularly appropriate for quality-control testing of waveplates. The system is also adaptable for slightly varying the retardation provided by a waveplate (or any other retarder device) in a given optical setup. To this end, the waveplate position may be precisely altered to introduce correspondingly precise adjustments of the retardation values that the waveplate provides. The system is further refined to permit one to compensate for errors in the retardation measurements just mentioned. Such errors may be attributable to static birefringence present in the optical element of the photoelastic modulator that is incorporated in the system.Type: ApplicationFiled: October 2, 2002Publication date: February 13, 2003Inventor: Theodore C. Oakberg
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Publication number: 20030002042Abstract: A polarization detector is described which contains a beam splitter, which disperses an incident light beam into partial beam paths. The partial beams pass though &lgr;/4 wafers and a cholesterol layer and impinge upon detectors. The polarization direction of the incident light beam can be measured by the polarization detector with the aid of the signal level of the detectors.Type: ApplicationFiled: May 21, 2002Publication date: January 2, 2003Inventors: Werner Spath, Ulrich Steegmuller
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Patent number: 6480277Abstract: A circular dichroism spectrometer eliminates linear birefringent interference by having a first polarization modulator before the sample and a second polarzation modulator after the sample. The two polarization modulators vibrate at different frequencies so the signals can be distinguished and manipulated. The addition of the second polarization modulator, an additional lock in amplifier, and software to manipulate the two signals corresponding to the two vibrational frequencies allow a real time circular dichroism spectra free from interference to be determined.Type: GrantFiled: October 18, 2001Date of Patent: November 12, 2002Assignee: BioTools, IncInventor: Laurence A. Nafie
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Patent number: 6473181Abstract: A practical system and method for measuring waveplate retardation. The system employs a photoelastic modulator (22) in an optical setup and provides high sensitivity. The analysis is particularly appropriate for quality-control testing of waveplates (26). The system is also adaptable for slightly varying the retardation provided by a waveplate (26) or any other retarder device in a given optical setup. To this end, the waveplate (26) position may be precisely altered to introduce correspondingly precise adjustments of the retardation values that the waveplate (26) provides. The system is further refined to permit one to compensate for errors in the retardation measurements just mentioned. Such errors may be attributable to static birefringence present in the optical element of the photoelastic modulator (22) that is incorporated in the system.Type: GrantFiled: January 21, 2000Date of Patent: October 29, 2002Assignee: Hinds Instruments, Inc.Inventor: Theodore C. Oakberg
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Patent number: 6449091Abstract: Tuning to maximize the isolation provided by an optical isolator to one of a predetermined plurality of wavelengths is achieved by tilting the isolator with respect to an input beam of light. Further tuning to a peak response for a given wavelength is achieved by rotation of the isolator about its longitudinal axis while or after tilting. In the manufacture of the isolator a test beam is launched into an output port end directed toward the input end. Tilting, or tiling and rotating is initiated and light at the input end is measured while tilting/rotating. When the position is determined where the minimal amount of light is measured, the optical elements are glued or secured in place, thereby providing a way to alter the response of an isolator for a given wavelength of input light.Type: GrantFiled: December 3, 1996Date of Patent: September 10, 2002Assignee: JDS Fitel Inc.Inventors: Yihao Cheng, Neil Teitelbaum
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Patent number: 6441959Abstract: The present invention provides a dispersion compensator which utilizes a Virtually Imaged Phased Array (VIPA), gratings, and birefringent wedges to moderate chromatic dispersion, dispersion slope and polarization mode dispersion, and a method and system for testing such a dispersion compensator.Type: GrantFiled: October 11, 2000Date of Patent: August 27, 2002Assignee: Avanex CorporationInventors: Jialing Yang, Simon Cao, Jiyong Ma, Christopher Lin
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Patent number: 6411384Abstract: The present invention provides a method for calculating the birefringence of an optical element and selecting the direction of minimum birefringence in the optical element. The birefringence of the optical element is calculated by converting known piezo-optical constants in a specified three-dimensional orthogonal coordinate system for the optical material into piezo-optical constants in an arbitrary three-dimensional orthogonal coordinate system. The amount of change in the refractive index &Dgr;n1 of the optical material in a first direction and the amount of change in the refractive index &Dgr;n2 of the optical material in a second direction which is perpendicular to the first direction are calculated using a uniaxial stress that is applied to the optical material along the first direction.Type: GrantFiled: December 27, 2000Date of Patent: June 25, 2002Assignee: Nikon CorporationInventors: Shigeru Sakuma, Shuuichi Takano
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Patent number: 6407042Abstract: A composition is disclosed for application to a plant that comprises an exogenous chemical (for example, a postemergent herbicide), an aqueous diluent, and a first excipient substance that is amphiphilic. The weight/weight ratio of the first excipient substance to the exogenous chemical is between about 1:3 and about 1:100. The aqueous composition forms anisotropic aggregates on a wax layer, and the presence of the anisotropic aggregates can be detected by a test described herein. Compositions of the present invention, when applied to plants, provide enhanced biological activity per unit amount of exogenous chemical, as compared to otherwise similar compositions containing surfactants that do not form anisotropic aggregates. Without being bound by theory, it is presently believed that this enhanced biological activity results from the formation or enlargement of hydrophilic channels through the epicuticular wax of the plant.Type: GrantFiled: March 24, 2000Date of Patent: June 18, 2002Assignee: Monsanto Technology LLCInventors: Anthony J. I. Ward, Jisheng Ge, Jane L. Gillespie, Joseph J. Sandbrink, Xiaodong C. Xu
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Patent number: 6323947Abstract: Improvements in accuracy and sensitivity in mechanical-optical metrology apparatus are achieved through the use of a value for angle of incidence that is an average of positive and negative values for different arrangements of the metrology apparatus. In the ellipsometry type of metrology the average value for angle of incidence is established by using one of a reversal of light beam direction, the providing of a separate light beam mounting arm and the mechanical rotation of the sample.Type: GrantFiled: December 14, 1999Date of Patent: November 27, 2001Assignee: Interface Studies CorporationInventor: John Lawrence Freeouf
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Patent number: 6320657Abstract: An ellipsometer, and a method of ellipsometry, for analyzing a sample using a broad range of wavelengths, includes a light source for generating a beam of polychromatic light having a range of wavelengths of light for interacting with the sample. A polarizer polarizes the light beam before the light beam interacts with the sample. A rotating compensator induces phase retardations of a polarization state of the light beam wherein the range of wavelengths and the compensator are selected such that at least a first phase retardation value is induced that is within a primary range of effective retardations of substantially 135° to 225°, and at least a second phase retardation value is induced that is outside of the primary range. An analyzer interacts with the light beam after the light beam interacts with the sample. A detector measures the intensity of light after interacting with the analyzer as a function of compensator angle and of wavelength, preferably at all wavelengths simultaneously.Type: GrantFiled: July 19, 2000Date of Patent: November 20, 2001Assignee: Therma-Wave, Inc.Inventors: David E. Aspnes, Jon Opsal
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Patent number: 6317209Abstract: An apparatus for making automated measurements of an optical property of a sample includes a first stage which is movable along a predetermined line, a second stage for holding the sample, and a third stage which is movable along a predetermined line, correspondingly to the motion of the first stage. A light source is mounted on the first stage, and a light detector is mounted on the third stage. The second stage rotates the sample to a selected rotary position. The apparatus also includes a controller for coordinating movement of the first, second, and third stages such that the light source, the sample, and the light detector are optically aligned.Type: GrantFiled: December 9, 1999Date of Patent: November 13, 2001Assignee: Corning IncorporatedInventor: Richard S. Priestley
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Patent number: 6268914Abstract: A dynamic self calibration process periodically calibrates a system for precisely measuring low-level birefringence properties (retardance and fast axis orientation) of optical materials. Variations in birefringence measurements can be caused by, for example, changes in the environmental conditions ( e.g., ambient pressure or temperature) under which birefringence properties of a sample are measured. In one implementation, the dynamic self calibration process repeatedly calibrates the system at different selected frequencies to compensate for different selected baseline variations.Type: GrantFiled: January 14, 2000Date of Patent: July 31, 2001Assignee: Hinds Instruments, Inc.Inventor: Baoliang Wang
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Patent number: 6266141Abstract: Transmission light from a detection lens is directed to a polarization element as incident light. The polarization element is rotated, and the light is received and detected by an array-state light-receiving element, and the birefringence of the detection lens is calculated. The distance between a lens for radiating the diffusion light onto the detection lens and the detection lens itself can be optionally set. Observing the transmission image of the detection lens, the distance between the detection lens and the lens is determined. Thereby, it is possible to obtain optical elasticity interference fringes which at most are scarcely affected by optical distortions. In addition, a focusing magnification rate is most suitably set to match states of birefringence occurrence which are different in accordance with the detection lens or the placement thereof.Type: GrantFiled: April 22, 1999Date of Patent: July 24, 2001Assignee: Ricoh Company, Ltd.Inventor: Nobuhiro Morita
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Patent number: 6252712Abstract: An optical system with at least one optical element that causes a disturbance of the distribution of polarization over the cross section of a light beam wherein at least one birefringent optical element is provided, with a thickness which varies irregularly over the cross section, such that the disturbance of the distribution of polarization is at least partially compensated.Type: GrantFiled: February 19, 1999Date of Patent: June 26, 2001Assignee: Carl-Zeiss-StiftungInventors: Gerhard Fürter, Winfried Kaiser, Christian Wagner, Michael Gerhard, Karl-Heinz Schuster
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Patent number: 6219139Abstract: A structural specimen coated with or constructed of photoelastic material, when illuminated with circularly polarized light will, when stressed; reflect or transmit elliptically polarized light, the direction of the axes of the ellipse and variation of the elliptically light from illuminating circular light will correspond to and indicate the direction and magnitude of the shear stresses for each illuminated point on the specimen. The principles of this invention allow for several embodiments of stress analyzing apparatus, ranging from those involving multiple rotating optical elements, to those which require no moving parts at all. A simple polariscope may be constructed having two polarizing filters with a single one-quarter waveplate placed between the polarizing filters. Light is projected through the first polarizing filter and the one-quarter waveplate and is reflected from a sub-fringe birefringent coating on a structure under load.Type: GrantFiled: October 5, 1999Date of Patent: April 17, 2001Assignee: Stress Photonics Inc.Inventor: Jon R. Lesniak
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Patent number: 6188811Abstract: A current sensor having an optmized optical fiber coil for sensing the magnetic field of a current of wire passing by or through the coil. The coil is optimally spun such that a particular ratio of the spin rate to the intrinsic polarization beat length is such for best maintenance of the circular polarization state of the light in the coil. The coil fiber may also be Terbium doped for greater sensitivity. The phase or birefringence modulation of the light may be piezoelectric or electro-optic. A Faraday rotator may be used in place of those modulators. The system may be open loop or closed loop. The feedback scheme may be via the modulator or the phase nulling current affecting the sensing coil.Type: GrantFiled: October 31, 1998Date of Patent: February 13, 2001Assignee: The Texas A&M Universtiy SystemInventor: James N. Blake
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Patent number: 6157448Abstract: The object of the present invention is to measure the amount of birefringence of a target while enhancing spatial resolution. A birefringence measurement optical system is comprised of a Stabilized Transverse Zeeman Laser emitting laser beam in a predetermined polarization state toward a target, a halfwave plate (polarized light emission optical system), a linear polarizer (polarized light detection optical system) detecting information on the retardation, main axial direction and optical rotation angle of the target as a light signal which can be polarimetrically analyzed through the target, and a photo detector converting the light signal from the linear polarizer into an electric signal and detecting the electric signal. An optical fiber (light transmission path) taking out part of light fluxes of the light signal and optically transmitting the part of the light fluxes from the target toward the photo detector, is arranged between the photo detector and the target.Type: GrantFiled: October 8, 1999Date of Patent: December 5, 2000Assignee: Uniopt Co., Ltd.Inventors: Hiroyuki Kowa, Norihiro Umeda, Shinji Mochiduki
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Patent number: 6157449Abstract: A method and apparatus for characterizing and scanning an array of material samples in a combinatorial library in parallel is disclosed. The apparatus includes a sample block having a plurality of regions for containing the material samples, a polarized light source to illuminate the materials, an analyzer having a polarization direction oriented 90.degree. relative to the polarization direction of the polarized light source so as to filter out light intensities having the same polarization direction as the incident light beams from the light source after illuminating the material samples, and a detector for analyzing changes in the intensity of the light beams. In one aspect, the light source in combination with a polarizer, includes a plurality of light beams to simultaneously illuminate the entire array of materials with linearly polarized light such that the characterization can be performed quickly.Type: GrantFiled: October 19, 1998Date of Patent: December 5, 2000Assignee: Symyx TechnologiesInventor: Damian A. Hajduk
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Patent number: 6097488Abstract: A method and apparatus for measuring microstructures, anistropy and birefringence in polymers using laser scattered light includes a laser which provides a beam that can be conditioned and is directed at a fiber or film which causes the beam to scatter. Backscatter light is received and processed with detectors and beam splitters to obtain data. The data is directed to a computer where it is processed to obtain information about the fiber or film, such as the birefringence and diameter. This information provides a basis for modifications to the production process to enhance the process.Type: GrantFiled: June 22, 1998Date of Patent: August 1, 2000Assignee: Princeton UniversityInventors: Boris Grek, Joseph Bartolick, Alan D. Kennedy
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Patent number: 6081337Abstract: The present invention relates to methods and apparatus for measuring the optical properties, eg twist angle, cell gap, input director, of a transmissive or reflective liquid crystal cell. For a transmissive liquid crystal cell the cell is placed between a polarizer and an analyzer and the transmission spectrum observed while rotating the analyzer until zero transmission is obtained at at least one wavelength. The twist angle and the surface rubbing orientations of the liquid crystal cell are determined by the relative angle between the polarizer and the analyzer while the cell gap is determined from the calculated retardation value d.DELTA.n with known .DELTA.n. For reflective cells cell gap is determined based on a knowledge of twist angle and is accomplished by observing zero reflection wavelengths from a reflective cell with the polarizer and analyzer in cross-orientation.Type: GrantFiled: May 5, 1998Date of Patent: June 27, 2000Assignee: The Hong Kong University of Science & TechnologyInventors: Hoi-Sing Kwok, Shu-Tuen Tang
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Patent number: 6067155Abstract: Infrared and visible light energies are directed through a container onto a CCD camera that is responsive to both the visible and infrared light energy. Crossed polarizers are positioned on opposed sides of the container, and operate on the visible light energy in such a way as to block transmission of visible light to the camera in the absence of stress variations in the container, which alter polarization of the visible light energy traveling through the container. On the other hand, the polarizers have little or no effect on the infrared light energy, which creates a normally gray intensity of background light at the camera. In this way, incidence of visible light on the camera due to stress variations in the container appears as a bright signal against a normally gray background, while blockage of infrared light due to opaque variations in the container appears as a dark signal against the normally gray background.Type: GrantFiled: December 24, 1997Date of Patent: May 23, 2000Assignee: Owens-Brockway Glass Container Inc.Inventor: James A. Ringlien
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Patent number: 6055053Abstract: A structural specimen coated with or constructed of photoelastic material, when illuminated with circularly polarized light will, when stressed; reflect or transmit elliptically polarized light, the direction of the axes of the ellipse and variation of the elliptically light from illuminating circular light will correspond to and indicate the direction and magnitude of the shear stresses for each illuminated point on the specimen. The principles of this invention allow for several embodiments of stress analyzing apparatus, ranging from those involving multiple rotating optical elements, to those which require no moving parts at all. A simple polariscope may be constructed having two polarizing filters with a single one-quarter waveplate placed between the polarizing filters. Light is projected through the first polarizing filter and the one-quarter waveplate and is reflected from a sub-fringe birefringent coating on a structure under load.Type: GrantFiled: June 2, 1997Date of Patent: April 25, 2000Assignee: Stress Photonics, Inc.Inventor: Jon R. Lesniak
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Patent number: 6049411Abstract: Light from a collimated light source which is incident on a birefringent detector at a predetermined optimum angle interacts with the birefringent detector and is viewed by an imaging transducer in order to produce an image which shows changes in the birefringence of the birefringent detector caused by acoustic energy which has interacted with an object, the image thus showing heterogeneities in the object.Type: GrantFiled: October 14, 1998Date of Patent: April 11, 2000Assignee: SanTec Systems IncInventors: Jaswinder S. Sandhu, Witold J. Popek, Hongui Wang
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Patent number: 6043887Abstract: The state of polarization of an input light beam is tested by determining four components of a Stokes vector of the light. These correspond to components of the light in three polarization states, S.sub.1 : linear horizontal, S.sub.2 : linear at 45 degrees, S.sub.3 : right circularly polarized, and S.sub.0 the total power. It is not necessary to filter out these components directly and measure their powers. In accordance with this invention it is more convenient to measure the powers in three arbitrary polarization states that have known relationships to each other, and, also measure the total power. The actual Stokes vector components is calculated from this information. Conveniently, a device having three polarization beam splitting surfaces and a prism provides a novel way in which to obtain the necessary information from an input beam so that a set of equations can be solved to determine the state of polarization the input beam.Type: GrantFiled: November 27, 1998Date of Patent: March 28, 2000Inventors: Louis B. Allard, Robert I. MacDonald, Carey M. Garrett
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Patent number: 6034777Abstract: Disclosed is a method for evaluating parameters in parameterized equations for independently calculating retardence entered to orthogonal components in a beam of electromagnetic radiation which is caused to pass through spatially separated input and output windows, by each of said input and output windows. The present invention finds application in ellipsometric investigation of sample systems present in vacuum chambers, wherein a beam of electromagnetic radiation is caused to pass through an input window, interact with a sample system, and exit through an output window, and where it is necessary to separate out the effects of said input and output windows to arrive at sample system characterizing results.Type: GrantFiled: September 29, 1998Date of Patent: March 7, 2000Assignee: J.A. Woollam Co. Inc.Inventors: Blaine D. Johs, Craig M. Herzinger
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Patent number: 6023332Abstract: A device for measuring birefringence in an optical data carrier has a laser light source with a polarization modifier, a beamsplitter, a polarizer, a photodetector, and a controller operatively connected to the photodetector. The laser light source illuminates various spots on the optical data carrier by means of a laser beam. The photodetector receives a reflected laser beam, converts it into an electric signal and supplies this signal to the controller, which determines a value for the birefringence in the illuminated spot on the optical data carrier. Furthermore, the device is provided with a transparent reference element with known birefringence properties, a mirror, and for directing the laser beam towards the reference element in a first calibration position; directly towards the mirror in a second calibration position; and towards the optical data carrier during non-calibration time.Type: GrantFiled: January 14, 1999Date of Patent: February 8, 2000Assignee: Ifunga Test Equipment B.V.Inventors: Hakan Bergstrom, Ulf Wilhelmson, Lars Jonsson
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Patent number: 6016053Abstract: The voltage transformer has a measuring element in the electrical field between an internal conductor and an external conductor of a metal-encapsulated, gas-insulated switchgear. The measuring element includes a Pockels crystal, a crystal of transparent material which, under the influence of the electric field, influences polarized light that is radiated through on account of the Pockels effect. The Pockels crystal has two parallel walls transverse with respect to the field lines. A first deflection prism, which deflects a light beam through 180.degree., is disposed on the crystal face at the high-voltage end. Several optical elements are disposed at the face on the low-voltage side. The optical elements include a light input coupler for polarized light and two light output couplers. The reflected light beam impinges on a beam splitter, which splits the light beam into two partial beams. The first partial beam radiates firstly through a quarter-wave plate and then through a first analyzer.Type: GrantFiled: August 26, 1997Date of Patent: January 18, 2000Assignee: ABB Patent GmbHInventors: Christopher Yakymyshyn, Michael Brubaker, Michael Schwarz, Alexis Mendez, Dirk Ebbinghaus
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Patent number: 5999240Abstract: A retarder stack for transforming at least partially polarized light includes a first retarder and a second retarder. The first retarder has a first retardance and a first orientation and the second retarder has a second retardance and a second orientation both orientations with respect to the partially polarized light. The first retardance, first orientation, second retardance, and second orientation can be arranged to yield the desired polarization transformed light which includes a first spectrum and a second spectrum. The polarization of the first spectrum and the polarization of the second spectrum can be made orthogonal to each other. The polarizations can be linear or elliptical. If the polarization transformed light is linear, the directions of polarizations are different and in one case can be made perpendicular.Type: GrantFiled: May 9, 1997Date of Patent: December 7, 1999Assignee: ColorLink, Inc.Inventors: Gary D. Sharp, Kristina M. Johnson
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Patent number: 5982174Abstract: A magnetometer uses a material exhibiting the Faraday effect, in which the polarization of light transmitted through the material is changed in response to a magnetic field. When the material is placed in a Fabry-Perot cavity, multiple reflections of the light within the Fabry-Perot cavity increase the change in polarization and thus the sensitivity of the magnetometer. Other effects that alter the polarization of light can be employed instead.Type: GrantFiled: July 21, 1997Date of Patent: November 9, 1999Inventors: Richard B. Wagreich, Christopher C. Davis
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Patent number: 5963326Abstract: The present invention discloses an ellipsometer using incident light having a wide beam diameter, comprising: a collimator for making the light parallel; a polarizer for transforming the light into a suitable linearly polarized state and radiating onto the sample; a beam expander for expanding the light to the size required for a single measurement; an objective lens composed of an afocal lens system for capturing the light reflected from the sample; an analyzer for converting the reflected light to suitable linearly polarized light; an imaging lens composed of an afocal lens system for forming an image of the sample on a image sensor; and, a image sensor; whereby, measurement of the polarized light can be performed at high speed and high resolution.Type: GrantFiled: November 25, 1997Date of Patent: October 5, 1999Inventor: Katsuya Masao
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Patent number: 5956146Abstract: A birefringence measuring apparatus 30 measures a birefringence of a transparent substrate D1 of an optical disc D having a reflective layer D2 thereon by detecting a reflected light beam L2, which is a reflection of a light beam L1 from the disc. The light beam irradiates the disc at an incident angle of ".alpha.", penetrates the transparent substrate, and reflected by the reflective layer. The light beam emitted from a light source 1 has a coherence length shorter than an optical path length P which is a sum of optical paths P1 and P2. The optical path P1 is a distance from the surface of the transparent substrate to the reflective layer, and the optical path P2 is a distance from the reflective layer to the surface of the transparent substrate.Type: GrantFiled: January 28, 1998Date of Patent: September 21, 1999Assignee: Victor Company of Japan, Ltd.Inventor: Eiji Nakagawa
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Patent number: 5936730Abstract: A bio-molecule analyzer including a plurality of test sites on a transparent substrate, each test site having probe molecules attached thereto. An array of addressable light sources are positioned in optical alignment with a corresponding test site. A solution containing sample molecules is positioned in contact with the plurality of test sites. A detector array having a plurality of photodetectors positioned in optical alignment with the array of addressable light sources, one photodetector corresponding to each light source, and a light filter positioned between the detector array and the plurality of test sites for absorbing the light from the light sources and transmitting the light from the test sites to the detector array.Type: GrantFiled: September 8, 1998Date of Patent: August 10, 1999Assignee: Motorola, Inc.Inventors: Barbara M. Foley, Wenbin Jiang, Davis H. Hartman, Huinan Yu, Sean Gallagher
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Patent number: 5933000Abstract: Two light signals pass through a series connection of a first multimode optical fiber, a first polarizer, a Faraday sensor device, a second polarizer an a second multimode optical fiber in opposite directions. The polarization axes of the two polarizers are set at a polarizer angle .eta. or .theta. to the natural axis of the linear birefringence in the sensor device with cos(2.eta.+2.theta.)=-2/3. The measuring signal is derived as the quotient of two linear functions of the light intensities of the two light signals after passing through the series connection.Type: GrantFiled: June 23, 1997Date of Patent: August 3, 1999Assignee: Siemens AktiengesellschaftInventors: Thomas Bosselmann, Peter Menke
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Patent number: 5929993Abstract: Disclosed is dual-polarizer based system, and method for continuously monitoring the "total film retardance" of a birefringent film, where "total film retardance" is defined as the product of the difference in the indicies of refraction in the two directions of refringence in said film, multiplied with film thickness. The preferred embodiment involves the application of Fourier analysis to signals which pass through the system and a birefringent film therein, to provide a spectrum, changes in which are indicative of changes in monitored "total film retardance". The present invention allows real time monitoring of birefringent films during manufacture thereof, and, hence, via a control system, control of film manufacturing process parameters to the end that produced films present with a relatively more consistent thickness than is the case where the present invention is not utilized.Type: GrantFiled: March 3, 1998Date of Patent: July 27, 1999Assignee: J.A. Woollam Co. Inc.Inventor: Blaine D. Johs
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Patent number: 5912457Abstract: A pressure sensor includes two birefringent media, one of which is exposed o pressure to undergo pressure-variable birefringence. Polarized light passes through the birefringent media to be modulated in accordance with the pressure and is then made incident on a photodetector to detect the modulation. The use of two birefringent media provides temperature compensation.Type: GrantFiled: December 30, 1996Date of Patent: June 15, 1999Assignee: The United States of America as represented by the Secretary of the ArmyInventor: Michael McQuaid
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Patent number: 5909311Abstract: An object reflector detecting apparatus for identifying an object reflector by emitting a light from a polarized light source toward the object reflector and then detecting a reflected light from the object reflector characterized in that the light emitted from said polarized light source is a polarized light of which direction of polarization is specially defined, the polarized lights between said reflected light and said emitted light are different in the direction of polarization, and said object reflector detecting apparatus is adaped to detect only a component of the direction of polarization from said object reflector.Type: GrantFiled: May 6, 1997Date of Patent: June 1, 1999Assignee: Kabushiki Kaisha TopconInventors: Fumio Ohtomo, Kunihiro Hayashi, Jun-ichi Kodaira, Hiroyuki Nishizawa, Kenichiro Yoshino
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Patent number: 5886810Abstract: An optical assembly comprising an optical element and a transducer is suspended within an enclosure so that the optical assembly is free to vibrate within the enclosure. In one embodiment, the mechanisms for suspending the assembly do away with any elastomeric material that would cause outgassing in applications where the photoelastic modulator is used in a high vacuum environment. The suspension system also increases the efficiency of the system.Type: GrantFiled: September 29, 1997Date of Patent: March 23, 1999Assignee: Hinds Instruments, Inc.Inventors: Massoud M. Siahpoushan, James A. Hinds, Richard R. Rockwell
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Patent number: 5864403Abstract: A system and apparatus for the measurement of absolute biaxial birefringence of plastic materials is described. The materials which must be at least partially transparent can be constituted of one or several similar or dissimilar layers. In the latter case, the birefringence of each material can be determined. The technique uses a multiwavelength white light source that provides at least two beams projected at different angles of incidence on the sample. The beams pass through first polarizers before they are incident on the sample and through second polarizers after they have passed through the sample. The beams are then directed to a detector for measuring each beam intensity or transmittance as a function of wavelength for the incident angles at different times, and are analyzed using nonlinear regressions to determine retardation. By the knowledge of the thickness of the material, the absolute biaxial birefringences are calculated for any specific wavelength.Type: GrantFiled: February 23, 1998Date of Patent: January 26, 1999Assignee: National Research Council of CanadaInventors: Abdellah Ajji, Jacques Guevremont
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Patent number: 5847872Abstract: The circumferentially isotropic phase plate of the present invention includes (i) a plurality of first material layers which are formed by a first material on a transparent substrate and disposed in concentric circles around a predetermined axis within a plane orthogonal to an incident direction of a bundle of rays and (ii) a plurality of second material layers which are formed by a second material having a refractive index different from that of the first material and disposed in concentric circles around the predetermined axis so as to fill a space between the plurality of the first material layers, wherein the plurality of the first and second material layers are formed such that each layer thickness along the incident direction of the bundle of rays becomes uniform along a circumferential direction of the concentric circles, thereby constituting, as a whole, a form birefringent body which is isotropic in the circumferential direction of the concentric circles.Type: GrantFiled: November 22, 1996Date of Patent: December 8, 1998Assignee: Nikon CorporationInventor: Yoshinobu Ito
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Patent number: 5835222Abstract: Disclosed is a system, and regression-based method utilizing optical data, for use in identifying material systems which have been cut to have an optical axis oriented as desired with respect to a alignment surface. The present invention is particularly well suited to qualification of material systems such as optical compensators and retarders, which ideally have an optical axis oriented perpendicular to, or parallel to, an alignment surface.Type: GrantFiled: July 31, 1997Date of Patent: November 10, 1998Assignee: J.A. Woollam Co. Inc.Inventor: Craig M. Herzinger
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Patent number: 5815270Abstract: An all fiber-optic in-line photopolarimeter is disclosed. This photopolarimeter replaces the conventional 1.times.2 coupler, bulk beamsplitter and accompanying optics with a single 1.times.5 star coupler. This system can measure state of polarization of light in a fiber in situ.Type: GrantFiled: July 29, 1997Date of Patent: September 29, 1998Assignee: Board of Supervisors of Louisiana State University and Agricultural and Mechnical CollegeInventor: Shing M. Lee
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Patent number: 5757494Abstract: The present invention is applicable generally to Spectroscopic Rotatable and Rotating Element Ellipsometers which utilize a relatively large range of wavelengths. Disclosed is a system and method for controlling the polarization state of a polarized beam of light so that it is in a range where the sensitivity of a Polarization State Detector used to measure changes in said polarized beam of light resulting from interaction with a Sample System, to noise and measurement errors etc., is reduced. Exemplified is a system, and method of use, for simultaneously setting both measured ellipsometric ALPHA, and ellipsometric BETA parameter values, (or equivalents), within ranges, in which ranges the sensitivity of transfer functions, and mathematical regressions which utilize said ellipsometric ALPHA and ellipsometric BETA values in the calculation of sample system characterizing PSI and DELTA constant values, to noise and errors in measurement etc., is found to be negligible.Type: GrantFiled: April 14, 1995Date of Patent: May 26, 1998Assignee: J.A. Woollam Co. Inc.Inventors: Steven E. Green, Craig M. Herzinger, Blaine D. Johs, John A. Woollam