Abstract: A modular flow-through cell is described which has main block member having a first pathway which leads from an inlet port to a large bore and a second passageway which leads from the large bore to an outlet port. A cartridge assembly is removably inserted into the large bore to provide an optical path for light to pass through a fluid sample.

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: Process and interferometric device for detecting and measuring the concentration, in a single operation, of all gases, having almost periodic absorption structures, contained in a gaseous mixture, each of the gases being associated with a characteristic path difference. Luminous flux is analyzed after passage through a cell containing the mixture, using to a multiple-wave interferometer, for example, a Fabry-Perrot interferometer, in which the inside faces of plates therein are highly reflective, and one of which plates is displaceable at a constant speed, it thus being possible to sweep a very wide range of path difference. Analysis of the output signal is performed frequency band by frequency band, by seeking the maximum.

Abstract: The invention relates to an optical fiber measuring device of the type in which variation of a measured parameter causes a difference of progression of light waves in the optical fiber. Such a device permits measurement of speed of rotation, or of current and magnetic field. The device includes an electronic device for digitally processing a signal indicative of phase shift of one light wave relative to another, the light waves propagating through a preferably monomode optical fiber in a SAGNAC ring interferometer, modulated by a phase modulator.

Abstract: A grating-interference type displacement meter apparatus is disclosed wherein a convex lens or a concave mirror is disposed such that a focal point thereof is placed on a refraction plane or a diffraction plane of a diffraction grating, or wherein zeroth-order beams transmitted through the diffraction grating are reflected back in the same direction by a rectangular prism or a triangular prism for reentrance thereof onto the diffraction grating. Hereby, a plurality of optical beams produced by the diffraction grating are directed to propagate parallely to directions of propagation thereof defined in its design.

Abstract: A measuring method and apparatus for measuring the shape of an optical surface using Fizeau interference is disclosed. The states of three surfaces are determined by measuring Fizeau fringes between all possible pairs of said surfaces. In at least one of these measurements means for reversing the coordinate axis in the beam is provided.

Abstract: An apparatus (12) generates information about the width of pulses in an optical train using an autocorrelation technique. In the apparatus, the incoming beam (10) is split into two paths (10a, 10b). The path length of one of the beams (10b) is varied using a reciprocating stage (40) having a reflector (50) mounted thereon. The stage is driven by a cam (42) rotating at a constant speed. A portion (42b) of the curvature of the cam is arranged such that the distance between the rotational axis (44) of the cam and the stage varies proportionally with the rotational angle of the cam such that the path length of the beam will change at a constant rate. The two beams are then recombined in a second harmonic generation crystal (28) which generates an output signal. The output signal is monitored by a photodetector (30) and may be displayed on an oscilloscope to provide a measurement of the pulse width of the input pulses.

Abstract: Pressure and temperature are sensed with first and second interferometers having beam paths originating at an optical fiber located at a collimating lens focal point. One interferometer includes a deformable membrane having a deformation responsive to the sensed pressure and temperature which cause the membrane position to vary with respect to a face of a glass plate. In the second interferometer the optical path length varies as a function of the sensed temperature. The collimating lens collects optical beams derived from the first and second interferometers and supplies them to the optical fibre. In one embodiment, the interferometers are coaxial and in parallel; in a second embodiment the interferometers are in series.

Abstract: In an on-line scanning sensor system, certain components of an FT-IR interferometer are isolated from vibrations that cause inaccuracies in measurements provided by the system, thereby allowing the sensor system to be used on-line in manufacturing environments. More particularly, vibration-absorbing suspension devices suspend selected interferometer components such that the center of suspension of the suspended interferometer component is substantially coincident with the center of gravity of the suspended components.

Abstract: A method of stress-optical force measurement where a linearly polarized light ray is guided into a stress-optical measurement array consisting of several measurement members on which the force to be measured acts in a distributed manner. The light ray successively traverses the measurement members while being influenced in a force-dependent manner and is applied to a subsequent evaluation unit for evaluation. The invention also relates to a measurement device for performing the method, comprising a measurement array and an evaluation unit between two plates which are arranged in parallel at a distance from one another. The measurement array consists of at least three spaced stress-optical measurement members which keep the plates at a distance from one another, influence the light ray in a force-dependent manner, and guide the light ray into the evaluation unit arranged between two measurement members.

Abstract: A heterodyning interferometric monitoring apparatus for simultaneously measuring in situ and in real time the optical and physical thicknesses of a sample during a deposition process. A linearly polarized monochromatic light beam is passed through a frequency shifter which produces therefrom a dichromatic light beam having two orthogonally linearly polarized components at respective different frequencies. The dichromatic beam is applied to a modified Twyman-Greene interferometer, from which two heterodyne light beams emerge. The first of the two light beams is a combination of light at the first frequency reflected from the sample and light at the second frequency reflected from a reference plate, from which the physical thickness of the sample can be determined using a heterodyne signal detector.

Abstract: An angular displacement interferometer system capable of measuring accurately changes in angular displacement comprises a source (10) of a frequency stabilized input beam with two linear orthogonally polarized components; a tilted parallel plate or shear place (16) with regions of reflection, antireflection, and polarizing coatings for converting the input beam (12) into two separated, parallel, orthogonally polarized beams (30, 31); a half-wave retardation plate (29) located in one of the separated beams (31) for converting the two separated, parallel, orthogonally polarized beams (30, 31); into first and second beams which are spatially separated parallel, and have the same polarization (30, 33); a polarizing beamsplitter (40) and quarter-wave retardation plate (44) for transmitting the first and second beams (34, 35) to a fixed plano mirror (70) nominally perpendicular to the first and second beams for reflecting the first and second beams back into the quarter-wave retardation plate (44), polarizing beams

Abstract: Apparatus and method for determining and recording a calculated impact point of one or more projectiles discharged from a firearm include a sighting mechanism with a field of view display unit, sensor elements, a recording unit, and a trajectory calculating microprocessor unit, the microprocessor unit for storing parameter data and for responding to sensor and/or manual data input signals and modifying the image presented by the field of view display unit. The trajectory calculating microprocessor unit, in response to the sensor data and parameter data, determines the trajectory of a projectile. The calculated impact point of the projectile is used to superimpose an indicia, namely an impact point-reticle on the image of the field of view of the display unit relative to the zero-range reticle or standard cross-hair setting.

Abstract: The invention relates to a straightness interferometer system, for measuring transverse deviations in the relative movement of machine parts. The preferred embodiment comprises a laser (30) which directs a single frequency laser beam, polarized in two orthogonal modes, along a principal axis P onto a beam splitter (24) which splits the beam into its two modes to provide two secondary beams (26,28). One of the secondary beams (26) is undeviated from the principal axis, the other (28) is deviated through a small angle. A roof-top reflector-prism combination (30/40) is positioned in the paths of both secondary beams in a plane normal to the principal axis, the prism being arranged to deflect the deviated beam into a direction parallel to the principal axis so that both beams are reflected back to the beam splitter where they re-combine to form a combined beam.

Abstract: A Dynamic Laser Speckle Profilometer (DLSP) apparatus and method are provided to preform nondestructive analysis of materials, components, and assemblies by creating an optoelectronic phase map. This phase map is used to generate the deformation and resonance mode mapping of an object under test. The Dynamic Laser Speckle Profilometer system is based upon the low optical noise design of a double pulsed laser speckle interferometer incorporating a single frequency polarized laser, a high bandwidth amplitude modulator, a phase modulator, a phase tracker, a range finder, and a light sensitive surface, all under computer control. This produces a series of interference images of an object under test. The dynamic laser speckle profilometer method uses a series of interference images, the Carre' phase algorithm, and recursive speckle elimination, to produce phase maps of the object under test.

Abstract: An apparatus for analysis of samples (E) by ellipsometry, and an analysis procedure. The light beam (F) passes through a polarizer (4), a rotating (omega) doubly refracting plate (5) and an analyzer (6). The measurement uses the second and fourth harmonics of the speed of rotation of the plate (5). Application in particular to the growth and etching of thin films.

Abstract: Disclosed is an apparatus for measuring particles or particulates in a fluid in a measuring cell provided with a measuring window through which a laser beam is projected or through which light scattered from the particles passes. The surface of the measuring window is spherical with a radius of curvature whose center is at a point on which the laser beam converges for measurement. With this arrangement, light focused on the convergence point or light coming from the point always passes through the interface between the window and the fluid in the cell at an angle that is normal thereto. Thus no reflection of the light passing through the window occurs at the interface with the result that fluctuations of the refractive index of the fluid in the cell do not effect the focusing point of the light.

Abstract: A highly sensitive apparatus for sensing the position of a movable member comprises an optical directional coupler providing four external ports. Light from a short coherence length diode laser is injected into the first port. The coupler serves as a beam splitter to direct one portion of the injected light to the member via the second port and a single mode optical fiber. Part of this one portion is reflected concurrently from the member and from the adjacent polished coating at the end face of said fiber back into said fiber and optically coupled via the third port to a photodetector to provide a signal whose amplitude is indicative of the position of the member, based upon the relative phase of said concurrent reflections.The other portion of the injected light is optically coupled to and via the fourth port to another photodetector for providing, as a reference, a signal proportional to the intensity of the injected light.

Abstract: An assembly and method for monitoring the alignment of a workpiece with respect to a reference. The assembly and method employ an element which preferably comprises a capability for optical phase conjugation. Advantage which can result from the use of the element include enhanced sensitivity to alignment variations for both large and very small angle deviations from the reference.

Abstract: Disclosed .[.in.]. .Iadd.is .Iaddend.an aligning and exposing method suitable for use in the production of LSIs. Coherent ray beams are applied from two directions to form .Iadd.an .Iaddend.interference fringe through interference of the coherent rays. A diffraction grid is disposed in the optic paths of the ray beams substantially in parallel with the interference fringe. The ray beams reflected .[.and.]. .Iadd.or .Iaddend.transmitted by the grid are converged by a lens system and the intensities of the ray beams are measured to detect the relative position between the interference fringe formed by two coherent ray beams and the diffraction grid, thereby to permit a highly accurate alignment of fine semiconductor element. The pitch of the grid on the substrate is selected to be n (n being an integer) times as large as the pitch of the interference fringe, so that the grid for alignment purpose is formed simultaneously with the formation of the LSI pattern by photolithographic technic.