Abstract: An apparatus and method for modified intrinsic state spectral analysis determines a proportion of a plurality of intrinsic structures of an optically active molecule. A spectropolarimeter generates a plurality of intrinsic spectra. Each of the plurality of intrinsic spectra is an intrinsic state vector corresponding to a plurality of intrinsic molecular structures. The spectropolarimeter also generates a spectrum for a sample of the optically active molecule. The sample spectrum is a sample state vector of the optically active molecule. A controller determines a plurality of estimate state vectors based on a plurality of perturbed intrinsic state vectors. Each of the plurality of perturbed intrinsic state vectors corresponds to a perturbed intrinsic structure. An optimum proportion of the plurality of perturbed intrinsic state vectors corresponds to each estimate state vector. The plurality estimate state vectors are matched against the sample state vector to determine a best match estimate state vector.

Abstract: A device for detecting defects (2, 3) in fibrous materials (4, 22) includes members (16, 17) for squeezing the material against a film (1), a separating member (24) downstream of the squeezing members for separating the fibrous material from the film, and an opto-electronic sensor (6) downstream of the separating member for imaging the film and defects. An image processing assembly (26, 44) is electrically connected to the output of the imaging assembly for sensing and counting the marks left on the film by the defects. A member (25) is provided for moving the film relative to the opto-electronic sensor. Various optical systems, particularly polarizers (9, 10), may be incorporated into the device.

Abstract: An optical measurement device is disclosed for evaluating the parameters of a sample. The device includes a polychromatic source for generating a probe beam. The probe beam is focused on the sample surface. Individual rays within the reflected probe beam are simultaneously analyzed as a function of the position within the beam to provide information at multiple wavelengths. A filter, dispersion element and a two-dimensional photodetector array may be used so that the beam may be simultaneously analyzed at multiple angles of incidence and at multiple wavelengths. A variable image filter is also disclosed which allows a selection to be made as to the size of the area of the sample to be evaluated.

Abstract: A sample is placed between a circular polarizer and an analyzer in an optical path between a monochromatic light source and a two-dimensional optical receiver. Parallel beams emitted from the monochromatic light source are converted into circularly polarized light by the circular polarizer. After transmitting the sample, the light is guided to the analyzer. While rotating the analyzer about the axis of the beams, image data are detected by optical receiver at a step of a regular rotation angle, and the detected image data are sampled to be sent to an image processing device in the next stage. On the basis of the image data, an operation is conducted on each pixel to obtain a relative phase difference due to birefringence of the sample, the two-dimensional birefringence distribution including the sign of the relative phase difference, and also the principal axis direction.

Abstract: In order to be independent of temperature when evaluating polarization-modulated light signals, DC and AC components from light power signals (S.sub.1, S.sub.2) are evaluated separately. The algorithm necessary for this purpose is specified.

Abstract: There is disclosed a method for measuring retardation .DELTA.nd of a liquid crystal cell in which a linearly polarized light beam is impinged upon a liquid crystal cell, the liquid crystal cell is rotated in a plane perpendicular to an optical axis of a measuring optical system so that the transmission through the liquid crystal cell for the light beam having a polarization parallel to that of the incident light beam becomes maximal, the wavelength of the incident light beam is varied to detect at least one wavelength .lambda..sub.s at which the transmission has an extreme and, finally, .DELTA.nd is calculated from .DELTA.nd=.lambda..sub.s .sqroot.m.sup.2 -(1/4) for the case of m-th minimal transmission or from .DELTA.nd=.lambda..sub.s .sqroot.m.sup.2 +m for the case of m-th maximal transmission.

Abstract: A polarimeter with a polarization state generator and a polarization state analyzer mounted together on a single rotary mount. This novel structure allows built-in alignment and synchronization of the polarization state analyzer and the polarization state generator. Because of this built-in alignment and synchronization, polarization properties of samples can be measured quickly, accurately, inexpensively, and reliably. The instrument can measure polarization properties of remote samples, without placing the sample inside the instrument. The surrounding lenses and mirrors are designed in such a way that light leaving the instrument will pass through the polarization state generator and light returning into the instrument will pass through the polarization state analyzer and onto a photodetector. Samples can be measured directly in reflection or in small-angle backscatter; or they can be measured in double-pass transmission with the addition of a mirror or retroreflector.

Abstract: An apparatus is provided for analyzing the polarization state a light beam. A rotatable disk provides, on a surface of the disk, a visual indicator and a centrally positioned polarizer. The indicator and polarizer rotate with the disk as a single unit. A drive motor is engaged with the rotatable disk for providing motive force in rotating the disk about its central rotational axis. A signal processing circuit includes an optical detector positioned on one side of the polarizer for receiving the light beam after the light beam passes through the polarizer. The optical detector produces a detector electrical signal of an amplitude generally dependent on the instantaneous rotational position of the rotatable disk, as such position is determinant of the light attenuating power of the polarizer on the light beam. The signal drives the visual indicator to produce a visual image as the disk rotates.

Abstract: High speed pattern and defect detection in flat panel displays, integrated circuits, photo mask reticles, CRT color masks, printed circuit boards, and any other patterned devices, regular or irregular, uses analog optical computing. Using appropriate illumination and optics, the Fourier transform of the image of a device under test is formed. The Fourier transform components of an ideal pattern are compared to the Fourier transform components of a measured pattern, and differences in relative intensities of the spatial components indicate a defect. A spatial separator is used to direct different components of the Fourier transform in different directions for parallel, simultaneous measurement and analysis. Utilizing Statistical Process Control, and properly comparing the different Fourier transform components, the defect is partially classified. Optical image processing is done in real time at the speed of light.

Abstract: A micropolarimeter comprises an analyzer (1) and a detector (3), which is typically a photodetector array. The detector has a circular configuration of a number N of sectors. Analyzer (1) and detector (3) form a unit with the analyzer assigning different polarization values to the sectors. Analyzer and the detector contain no moving parts. Three different embodiments are proposed for the analyzer: a glass cone, covered with a polarizing thin film stack, a metal grid polarizing array, and an array of polarizing waveguides. The micropolarimeter (14) is used preferably in a microellipsometer system which can serve as a tool for film diagnostics, especially optical characterization of thin films.

Abstract: A direct, noncontact temperature sensor includes an ellipsometer (104-106) to determine absorptance for layered structures and a pyrometer (102) to determine emissive power and combines the two measurements to determine temperature.

Abstract: Two linearly polarized beams of monochromatic laser light are amplitude modulated with low frequency sinusoids. The first laser is modulated with a sinusoid 90.degree. out of phase from the second laser. The two beams of laser light have their polarization axis fixed and separated by 45.degree.. These two beams are then collimated and combined into one composite beam using simple optics. This composite beam is then allowed to pass through an optically active substance of a calibrated path length. The laser radiation exiting the sample is passed through a optical notch pass filter, reducing any signal that may be present from any polarized ambient light by passing only light of the laser's frequency. The composite beam then passes into a beam splitting polarizing cube. This cube has the function of separating the beam into two orthogonal polarization components. The two beams of light exiting the cube are focused onto silicon photoelectric detectors.

Abstract: A method for assembling an optical isolator comprises a step for constructing a measuring system in which a light source, a lens system, a polarizer, an analyzer, and a light receiver are arranged in this order, and light projected from the light source and then transmitted through the lens system, the polarizer, and the analyzer, is received by the light receiver; a step for arranging optical elements for constituting a main body of the optical isolator between the polarizer and the analyzer; a step for measuring a maximum value and a minimum value in levels of the light received by the light receiver while the analyzer is rotated, thereby calculating a ratio of the minimum value to the maximum value; and a step for adjusting rotation positions of the respective components for constituting the main body of the optical isolator in order that the ratio becomes minimal.

Abstract: A polarization-modulation scanning laser microscope includes a conventional laser scanning microscope, which has been improved by addition of: a polarization state generator; a polarization state analyzer; a photo-detector for receiving laser light transmitted though a sample; a signal demodulator providing two signals in response to the transmitted laser light, one of the signals being indicative of polarization orientation, and the other signal being indicative of magnitude of the transmitted polarized light. A relay interface toggles between the two signals provided by the signal demodulator and at least one other signal provided either by the photodiode of the laser scanning microscope, or by an external optical beam induced current, or both. A signal processing unit provides an image output to a display device.

Abstract: A part for projecting a measuring light beam onto a sample and a light receiving part are arranged on the same side of a sample surface so that the measuring light beam is concentric with the light receiving part, the measuring light beam which is converted to a linearly polarized light beam through a polarizing element is projected to the sample so that the measuring light beam outgoing from the sample to the projecting side is received and detected through the same polarizing element. A plurality of sets of polarizing elements and light receiving parts are set so that the polarizing elements have different polarization directions, to calculate retardation from transmitted light intensity levels as obtained.

Abstract: A optical fiber polarimeter (10) includes a plurality of polarizing optical fibers (14) each having a different orientation with respect to a common reference line. A charge-coupled device having an array of pixels (32) is adapted to receive the light from the optical fibers (14) and generate a signal relating to the intensity of the light impinging on each pixel to a signal processor (18) that also orders the signals according to the orientation thereof and thereby provides a polarization phase versus intensity signal output.

Abstract: An ellipsometer has a nonpolarization beam splitter (18) for dividing reflected light (17) from an object to be measured (16) into portions traveling along first and second optical paths (18a, 18b), an analyzer (19) for passing the polarized light component in a reference direction of the reflected light portion traveling along the first optical path, and a polarization beam splitter (20) for dividing the reflected light portion traveling along the second optical path into two polarized light components in different directions with respect to the reference direction. The light beams passing through the analyzer (19) and polarization beam splitter (20) are sensed by first, second and third photodetectors (21a, 21b, 21c), respectively. In a coating thickness control method, first and second ellipsometers (35a, 35b) are placed before and after a coating apparatus (36) provided along the transport path of a belt-like plate to be coated (31). A first ellipsoparameter (.DELTA.1,.psi.

Abstract: A first polarizer and a second polarizer are located in an opposing relationship to each other on the optical axis of incident light with their polarization directions displaced from each other by a predetermined angle. A liquid crystal cell is arranged between the first polarizer and the second polarizer for rotation around the optical axis of the incident light. The incident light is introduced into the first polarizer while the liquid crystal cell is rotated. Transmission light, which is the incident light that has been transmitted successively through the first polarizer, the liquid crystal cell, and the second polarizer, is received by a photo-detector. The ratio between a variable component and a fixed component of the intensity of the transmission light is calculated. The cell gap of the liquid crystal cell is determined from the calculated ratio.

Abstract: In order to efficiently obtain data for calculating retardation values at a plurality of wavelengths, a sample having birefringence is placed between a polarizer and an analyzer, which are maintained in a parallel nicol relation to each other and rotated about an optical axis of measuring light. White measuring light is applied through the polarizer so that the light being passed through the sample and transmitted through the analyzer is received by a polychromator. A one-dimensional optical sensor is arranged on an outgoing imaging surface of the polychromator, to simultaneously detect transmitted light intensity values of a plurality of wavelengths. Since transmitted light intensity values of a plurality of wavelengths are obtained every polarization rotation angle of the polarizer and the analyzer, it is possible to obtain dispersion of retardation values with respect to wavelengths and the like by processing the data.

Abstract: Known polarization image detection systems produce an image illustrating structural information of a viewed scene which is representative of the degree of linear polarization. The present invention describes an improved detector system which enables more information to be extracted from the scene. The system comprises an optical arrangement having an optical axis (4) about which a retarder (1) and a linear polarizer (2) can be independently rotated, for producing a focussed image on a detector. This arrangement can be expressed mathematically in terms of Stokes parameters and Mueller matrices, and the expression can then be solved to provide three different polarization images representative of the viewed scene.

Abstract: Polarization dependent loss (PDL) of an optical component is computed in a deterministic method that requires only four measurements, each having a unique input state of polarization.

Abstract: A division-of-amplitude photopolarimeter based on conical grating diffraction includes a diffraction grating and at least four photodetectors. An incident light beam is directed at the grating at an oblique incidence angle .PHI. and the grating grooves are inclined at an arbitrary angle .alpha. with respect to the plane of incidence. Each of the photodetectors is positioned to intercept one of the diffracted orders and may be an area array detector if spectropolarimetry use is desired. Polarizing means may be inserted in the paths of one or more of the diffracted orders. A division-of-amplitude photopolarimeter based on planar grating diffraction includes a diffraction grating and at least four photodetectors; the grating is placed in the conventional spectrometer orientation with its grating grooves perpendicular to the plane of incidence.

Abstract: Movable optical parts included in an ellipsometer are omitted to increase the measurement speed and maintain constant, high measurement precision in film thickness measurement processing. A beam is radiated from a light source section onto a measurement target. A reflected beam having an elliptically polarized beam reflected by the measurement target is divided into four light components polarized in different directions. The optical intensities of the respective polarized light components are detected. Of the four detected optical intensities, one having the minimum value is omitted, and ellipsometric parameters .psi. and .DELTA. are calculated by using the remaining three optical intensities having the largest values. The ellipsometer comprises only stationary optical parts without using any movable optical parts. The polarization directions of the respective polarized light components, from which four optical intensities are obtained, are set at angles of 90.degree., 0.degree., +45.degree., and -45.degree.

Abstract: A spectroscopic ellipsometer comprises a wideband light source, together with a first optical system including a rotating polarizer which applies a parallel beam to a sample contained in an enclosure. The reflected beam is picked up by an analyzer in a second optical system which transmits said reflected beam to a monochromator which is followed by a photodetector which is connected to control electronics connected, in turn, to a microcomputer. An optical fiber is provided between the source and the first optical system. Advantageously, a second optical fiber provided between the second optical system and the monochromator.

Abstract: A method of calibrating polarimeter to work at an unknown wavelength comprising calibrating the polarimeter at a standard wavelength, using the calibrated polarimeter to measure a sample, measuring the same sample at the unknown wavelength and setting the polarimeter to give the same measurement at the said unknown wavelength as at the known wavelength. The method is particularly applicable to be calibration of a saccharimeter to work at an unknown wavelength in the near infra-red for the measurement of dark sugar samples. The invention is also a polarimeter or saccharimeter for carrying out the method.

Abstract: Movable optical parts included in an ellipsometer are removed to increase the measurement speed, and a specific quadrant to which a phase difference .DELTA. as an ellipsometric parameter belongs is determined by one measuring operation. A beam is radiated from a light source section onto a measurement target, and the reflected beam having an elliptically polarized beam, which is reflected by the target, is divided into four different polarized light components. The optical intensities of the respective light components are then detected. Ellipsometric parameters .psi. and .DELTA. are calculated on the basis of the detected four optical intensities. In addition, the above-mentioned four different polarized light components are obtained by using a wave plate. Furthermore, the polarization directions of the four polarized light components whose optical intensities are obtained are respectively set at angles -45.degree., +45.degree., 90.degree., and 0.degree. with respect to a reference direction.

Abstract: In a first step, the value of the synthetic retardation and the direction of the synthetic optical axis as angle data of a transparent substrate having a thin film thereon are measured. In a second step, the value of the retardation and the direction of an optical axis as angle data of only the transparent substrate are measured.

Abstract: A bottle stress analysis system using polarized light for determining stress levels of a transparent plastic bottle includes a rotation assembly for rotating the bottle. A polarized light source assembly is insertible into the bottle cavity to direct plane polarized light through the bottle wall and an analyzer assembly is positioned outside the bottle for measuring intensity of light passing through the bottle wall. In order to measure changes in polarization, the analyzer assembly has a polarization analyzer positioned to transmit the light to a photodetector. A mechanism for rotating either the polarized light source or the analyzer to determine maximum and minimum polarized light intensity at the photodetector facilitates determination of stress at a plurality of points along the bottle wall.

Abstract: Phas difference controller for use in equipments having a photoelastic modulator, such as ellipsometers and optical rotatory dispersion meters. For enabling the photoelastic modulator to produce the constant amplitude of the phase difference regardless of the change in the wavelength of light incident into the photoelastic modulator, and regardless of the change in the temperature of the photoelastic modulator itself or its atmosphere, the controller has a birefringence polarizer which splits incident light into two linearly polarized light beams, ordinary light and extraordinary light. One of them acts as reference light LR and the other one acts as main light LM. These light beams pass through a photoelastic modulator which is forced to vibrate at angular frequency of .omega.. After that, the passed reference light LR is detected by a photomultiplier via an analyzer. The photoelastic modulator is forced to vibrate at angular frequency of .omega.

Abstract: A method and an apparatus to re-calibrate a polarimeter without a standard source with known polarization. An input electromagnetic wave is sequentially transformed into many electromagnetic waves, all having substantially the same degree of polarization and at least three of the electromagnetic waves having different states of polarization. All the electromagnetic waves are measured by the polarimeter. The method then calculates a calibration factor which, when applied to the measured signals, generates substantially the same calculated degree of polarization for all the electromagnetic waves. A birefringent material, such as a wave-plate, can be used to generate the electromagnetic waves from the input electromagnetic wave. If the input electromagnetic wave is an optical wave, then loops of optical fibers or an electro-optic material, such as a LiNbO.sub.3 crystal, is used as the birefringent material.

Abstract: The invention concerns apparatus for monitoring optical fibers by detecting variations in the polarization of light being transmitted through the fibers. In one embodiment the optical fibre carries non-coherent light and the incoming light is split by a passive splitter (2) connected to a polarization beam splitter (5). Variations in the output of this polarization beam splitter are detected, amplified and filtered so that they can be compared with a preset reference voltage. A counter (12) is used to detect variations. Another embodiment relates to the detection of polarization variations in coherent systems.

Abstract: A polarization and birefringence measuring device has an optical source which causes a wide polarized light beam to impinge on a specimen. A photodetecting sensor having picture elements in two dimensions detects a light beam containing information about the specimen. A analyzer is situated in front of the photodetecting sensor and rotated to vary the amount of light which is transmitted. A frame memory memorizes the intensity of each picture element in the photodetecting sensor, and a computer determines the polarization state of parts of the specimen coresponding to the intensity of each picture element sampled. The computer samples the output of the photodetecting sensor when the rotation angle of the analyzer has reached a specified value, and this is memorized by the frame memory.

Abstract: An infrared laser polarimeter system for measuring the Mueller matrix of a sample is described which comprises, a infrared laser source for projecting a beam of preselected wavelength (preferably 3-14 .mu.m) along an optical axis, at least one polarizing element disposed along the axis for linearly polarizing the beam and producing an output beam for analysis, first and second rotatable optical retarders disposed between the source and polarizing element and defining a sample region therebetween, the second retarder being rotated at least five times that for the first retarder, an integrating sphere, and a detector for analyzing the output beam.

Abstract: A thickness of a liquid crystal cell is measured by placing a liquid crystal cell having a twist angle of .theta. between a polarizer and an analyzer, by measuring the strength of transmitted light through the analyzer with the polarizing angle of the polarizer tilted by 45.degree. from the orientation of the liquid crystal cell at its entry surface, and the polarizing angle of the analyzer tilted by further 45.degree. from the orientation of the liquid crystal at its output surface, by calculating retardation d.DELTA.n from the measured light strength, and by deriving a cell thickness d from both the retardation d.DELTA.n and a known birefringence .DELTA.n of the liquid crystal cell. Since this method provides the distribution of thickness data of liquid crystal cells, good quality liquid cells with uniform construction and thus without color shade can be selected.

Abstract: A modulated Faraday rotation signal is produced by passing a linearly polarized laser beam through a semiconductor wafer sample in a modulated magnetic field that is induced in an electromagnet by a sine wave generator and driver coupled thereto. The rotation signal is normalized by dividing by a transmission signal produced by modulating the beam with a chopper that operates at a different frequency from the frequency of the driver. The result is a Faraday rotation measurement with high signal-to-noise ratio and compensation for laser drift in intensity.

Abstract: An optically based apparatus for non-invasively determining the concentration of optically active substances in a specimen comprises, a source of a beam of spatially coherent light which is acted upon to produce a rotating linear polarized vector therein. A beam splitter splits the beam into a reference beam and a detector beam for passage through the specimen. The detector beam is received upon exiting the specimen and compared with the reference beam to determine the amount of phase shift produced by passage through the specimen. This amount of phase shift is converted into concentration of the optically active substance in the specimen.

Abstract: A method and apparatus for measuring a physical magnitude by means of an incoherent light source (10), an interferometric sensor (14) modulating the spectrum of the light beam emitted by the source at a characteristic frequency which is a function of the magnitude to be measured, a demodulator interferometer (18), and spectrum analysis means (22) having optical resolution making them insensitive to the modulation frequencies generated by the sensor (14) and the demodulator interferometer (18), and sensitive to the difference therebetween. The invention is particularly applicable for measuring physical magnitudes such as temperature, motion, electric field, etc.

Abstract: The ellipsometer and method involve directing polarized light for interaction with an optical system under study at different angles of incidence from a single beam of light and detecting the light interacted with the optical system by reflection and/or transmission for each of a plurality of different angles of incidence. The simultaneous illumination of the optical system under study at a whole range of angles of incidence from a single beam of light and the collection a large multiplicity of data from the different angles detected can be accomplished rapidly and easily and with accuracy without scanning and with only one ellipsometer. A lens is used to focus the incoming light to provide the range of different angles of incidence. The range of angles is at least one or two degrees and preferably thirty degrees or more. A second lens refocuses the interacted light to a linear, multi-element detector array which extends in the plane of the incidence.

Abstract: In a solar vector magnetograph for measuring solar magnetic fields including a telescope pointable to a solar zone and relay optics mounted there-behind, including a collimating lens, a quarter wave plate, a light polarizer, a beam expanding means, a narrow bandpass blocking filter to admit a narrow spectral band of polarized light, a reimaging lens to focus the resulting beam and an image receiver, the improvement provided is a solid Fabry-Perot etalon filter which is mounted between the blocking filter and the reimaging lens, such filter being of a desired refractive index and thickness so as to select a narrow band of the so-transmitted polarized light and to transmit same to the image receiver, all in order to isolate and record the emissions of atomic species and to infer the magnetic field at the solar zone.

Abstract: Two arrangements are disclosed to provide high resolution measurement of sub-micrometer and micrometer particle size distributions. In a first arrangement, scattered light is measured over a wide range of scattering angles. At the same time, light scattered at low scattering angles is measured with high angular resolution. In the second arrangment, an improved Polarization Intensity Differential Scattering (PIDS) measurement is made possible by providing an interrogating light beam of selected wavelength including a first component having a linear polarization plane and a second component having a differential linear polarization plane, wherein the linear polarizations of the components are orthogonal. Photodetecting arrays in one or more scattering planes detect light scattered by the particles at least at two scattering angles.

Abstract: Apparatus and method for determining dynamically the polarization vector direction, or polarization vector components and associated temporal phase angle, of a light beam. The apparatus includes a compact polarization beam splitter that receives a beam of light, separates the beam into two perpendicular polarization components and directs these components to a pair of optical detectors and associated circuits that form the sum and difference signals of the electrical signals produced by the optical detectors. This produces a projection of the polarization vector on a given direction. If the light is generally elliptically polarized, use of two such polarization beam splitters and four optical detectors allows reconstruction of the polarization ellipse for the light beam. Alternatively, use of one such polarization beam splitter, two optical detectors and a rotating wave plate in a multiplexed configuration allows reconstruction of the polarization ellipse.

Abstract: A method of and an apparatus for rapidly determining the polarization state of an incoming beam of light, such as from a fibre optic. The incoming beam is passed through a beam expander and then four separate portions of that beam are passed simultaneously through four Stokes filters respectively, arranged in a common plane. The four filtered beam portions are directed by respective lenses on to four detectors providing electrical signals indicative of the intensity of the respective filtered beams. From these four signals, the Stokes parameters may be deduced. The method allows very rapid assessments of the polarization state of an incoming beam to be achieved, and a bandwidth of several tens of KHz is attainable.

Abstract: A means of mapping the polarization across a laser beam 1 comprising the steps of dividing the laser beam into six beams 11, 12, 21, 22, 31, 32 each having a different polarization and phase. Measuring the intensity of each beam in charge coupled devices 111, 112, 121, 122, 131, 132, having an array of pixels. Matching the pixels in each array to their proper portion in laser beam 1. Adding the values obtained in each pixel to obtain a composite polarization map.

Abstract: In a driving mechanism for driving an oscillating polarizer in a polarimeter, the polarizer is driven by a stepper motor which is controlled by a computer to make a reciprocating movement. A reference position sensor is connected to the oscillating polarizer, to provide a reference signal when the oscillating polarizer is in a determined position. A zero position of the reference position sensor is obtained by spacing the reference position sensor a predetermined number of steps of the stepper motor.

Abstract: A method and apparatus for the automatic analysis of stress in a body. The device includes a measuring head and an apparatus for traversing the measuring head across a photosensitive material attached to the body. The measuring head measures the intensity of light reflected or dispersed from the photosensitive material. The reflected or dispersed light is emitted from and received by diodes in the measuring head. Electrical signals representative of the intensity of light traversing the photosensitive material in three directions are generated for each of a set of points on the photosensitive material. The electrical signals are analyzed by computer and converted to stress and strain data which may then be displayed on a plotter or monitor.

Abstract: A polarimeter for measuring the rotation of optically active samples comprises a light source which generates a measuring light beam, a polarizer mounted for rotation about the beam axis of the measuring light beam, a driving mechanism for reciprocating rotational movement of the polarizer, a sample vessel, an analyzer behind the sample vessel, a photoelectric detector, and balancing means which are controlled by the signal of the photoelectric detector and by which a position can be achieved in which the polarizer and analyzer are arranged substantially crosswise. The balancing means comprises a steeper motor for rotating the polarizer with an adjusting movement superimposed by the reciprocatingly rotational movement by which adjusting movement a quick coarse balancing of the polarizer plane of the measuring light beam relative to a zero position of the analyzer is achieved.

Abstract: The combination of a polarizer and an analyzer, and a sample interposed therebetween are rotated relative to each other to determine the relationship between the angle of rotation and the intensity of light transmitted through the arrangement. The birefringence of the sample is obtained from the retardation values calculated from the result of the determination. When the determination is made for two kinds of light with different wavelengths close to each other, the retardation can be determined straightforwardly. When at least three kinds of light with different wavelengths are used for the determination, different retardation values are obtained for the respective wavelengths for a highly accurate analysis.

Abstract: Two arrangements are disclosed to provide high resolution measurement of sub-micrometer and micrometer particle size distributions. In a first arrangement, scattered light is measured over a wide range of scattering angles. At the same time, light scattered at low scattering angles is measured with high angular resolution. In the second arrangement an improved Polarization Intensity Differential Scattering (PIDS) measurement is made possible by providing an interrogating light beam of selected wavelength including a first component parallel to the scattering plane and a second component perpendicular to the scattering plane. Photodetecting arrangements detect light scattered by the particles at least at two scattering angles.

Abstract: Apparatus for identifying a particulate substance in suspension based on the radiation scattering behavior of the substance, which apparatus includes a source of a collimated beam of substantially monochromatic radiation which is linearly polarized along a first polarization axis, at least two modulators disposed in the path of the polarized beam for effecting polarization modulation of the polarized beam about respective dynamic axes at respective modulation frequencies, a sample of the substance being held in the path of the beam between the modulators so that radiation is scattered by the substance in a scattering plane, a polarizing device disposed in the scattering plane for passing that portion of the scattered radiation which is parallel to a second polarization axis, and a signal processing device for producing an indication of the intensity of the radiation emerging from the polarizing device at frequencies corresponding to selected elements of a Mueller matrix which characterizes the scattering prop

Abstract: An optically sensing device is made up of the sensor materials that cause the value of birefringence to vary itself in accordance with external physical volume; a polarizer and an element provided with two total reflection surfaces causing the beam path to invert its direction by an angle of 180.degree.. The optically sensing device has the capability of setting the phase bias by applying the two total reflection surfaces causing the beam path to invert its direction by an angle of 180.degree.. Since each element has different functions, one functioning as a mirror and the other as a quarterwave plate, the optically sensing device is of extremely simple structure and is compact. In addition, since the optically sensing device provides a constant phase bias unlike the unstable performances of conventional quarterwave plates, it guarantees high-precision performance. Also, the use of inexpensive elements ensures reduced cost.