Abstract: A passive ring resonator gyroscope comprising a single piece body having an integral first and second resonator cavity. The first resonator cavity has a single frequency laser means with internal cavity mounted reflective surfaces to provide a single frequency light source to the second resonator cavity. The single frequency light source is sharply tuned. The second resonator cavity is a passive high Q evacuated cavity having a closed second optical path tuned to resonate at the single frequency light frequency of the first resonator cavity. A cavity servo means is provided for controlling the resonant frequency of the second resonator high Q cavity to simultaneously and substantially track the resonant frequency of the first resonator high Q cavity. An output servo means is provided for detecting the change in frequency of the single frequency light within the second resonator in response to said body rate input to the sensitive axis and for providing an output signal.

Abstract: A passive ring resonator gyroscope comprising a single piece body having an integral first and second resonator cavity. The first resonator cavity contains a single frequency laser that provides a sharply tuned single frequency light source to the second resonator cavity. The single frequency light source is split to form first and second sources. The second resonator cavity is a passive high Q cavity with a closed second optical path. The two light sources are fed into the second resonator and propagate as CW and CCW beams within the second resonator. A first servo channel develops a first control signal to tune the frequency of the CW beam to a resonance peak. A second servo channel develops a second control signal to tune the CCW beam to its resonance peak. By converting both servo error outputs into frequency, the relative frequency difference between the CW and CCW beams are recorded as the frequency shift in response to the body rate rotation about the sensitive axis.

Abstract: In an angular rate sensor including a plurality of thin film waveguides and a directional coupler, a plurality of interdigitated transducers arranged to propagate energy into the waveguides and detect the resulting counterpropagating waves.

Abstract: Setting the driving signal of a phase modulator in the sensing loop of a fiber optic gyroscope to zero for a period of time .tau. equal to the transit time of the light waves through the gyro causes the gyro to assume a known zero reference state. In this zero reference state the counterpropagating light waves are in phase except for the phase shift caused by rotation of the sensing loop. During this zero reference state, a biase signal for demodulation purposes and a signal that will cause a phase shift equal and opposite to the rotation-induced phase shift are applied to the phase modulator. These signals null the rotation-induced phase shift as seen by a photodetector for a period equal to the transit time.

Abstract: A system for carrying out holographic interferometry utilizes the same pulsed laser both for the exposure of holograms and for the reconstruction of combined wavefronts resulting from the exposure of a test object to two time spaced laser pulses. This enables the real-time observation of fringes due to interference due to deformation of a test object between timed spaced laser pulses. Pulses used to reconstruct the combined wavefronts are synchronized to the field interval of a video camera associated with a frame grabber so that the combined image may be presented on a video monitor as a continuous flicker-free image. The combined wavefronts may be obtained from separately exposed holograms, from a hologram together with a direct image of an object produced by the same pulse used to reconstruct the hologram, or from a single hologram double exposed by two laser pulses.

Abstract: A calibration disk used for an optical disk inspection unit to correct the measurement values of the mechanical characteristics, such as plane deflection and eccentricity of optical disks, and comprising at least one of three correction sections: an axial displacement correction section, a radial displacement correction section, and a focus error output voltage correction section which are formed on one or both sides of the calibration disk, concentric to the center of rotation of the disk so that measurement values, such as the surface deflection, can be corrected automatically and accurately by simply setting the calibration disk on an inspection unit.

Abstract: A high power solid state semiconductor fiber optic ring laser which includes an optical amplifier diode having its waveguide region oriented at an angle between Brewster's angle and 0.degree. with respect to the normal to the diode cleavage planes together with antireflection coatings disposed on the diode cleavage planes. The optical amplifier diode being optically coupled with the ends of an optical fiber.

Abstract: A dither drive system for a ring laser gyroscope includes a computer, a digital to analog converter, a filter, and a power amplifier. The system senses the dither frequency of the gyro frame and produces a digital signal that corresponds to a specified dither drive signal and toggles the dither drive signal to drive the flexure at its resonant frequency. The dither drive system generates digital waveforms that approximate the sine function and digital waveforms that approximate the cosine function and applies the digital waveforms in quadrature to the flexure.

Abstract: A shim for use in defining a fluid passage in a particle detecting fluid cell has a base portion of metal and head portion, defining the fluid passage, which haws a metal core and a covering which is non-corrodible by water and acid. The sides of the covering and the base portion define continuous flat surfaces which are sandwiched between plates defining the other boundaries of the flow passage. The coverings form a fluid tight seal with the plates and the base portions of the shims bear the compressive forces exerted on the shims by the plates.

Abstract: A displacement measuring apparatus has an illuminating device for illuminating a diffraction grating with a radiation beam, an optical system for directing first and second diffracted beams created by the diffraction grating with to the diffraction grating, the optical system being provided so that the first and second diffracted beams have a common optical path and travel in opposite directions along the optical path. In addition, a device receives an interference beam formed by first and second re-diffracted beams created by the first and second diffracted beams being diffracted by the diffraction grating, and outputs a signal conforming to the displacement of the diffraction grating relative to the radiation beam.

Abstract: A cell for holding a fluid medium for passing a beam of laser radiation through it to generate Raman shifted radiation is provided with a vaned agitator designed to effect flow of the fluid within the cell across the beam path, so that there is continually provided a fresh column of the optical medium within the beam path.

Abstract: A collimator solid state laser light source is spun at a very high speed to generate a reference plane for use in the construction industry. The drive housing and the laser light source are extremely compact, light and portable, and can be mounted to a surveyor's transit and telescope. Within the housing is a drive shaft which has the laser light source attached at precisely 90 degrees to the spin axis of the drive shaft. A logic circuit is also attached to the drive shaft so that the logic circuit board, the drive shaft, and the laser light source are all rotated as a unit. An electric motor and a motor control board card are positioned within the housing for rotating the drive shaft. The operator first calibrates the transit so that it is horizontal and positioned in plumb above the reference point.

Abstract: A fine surface profile meter includes an X-Y stage, supported by a leaf spring, for supporting a sample thereon, a piezoelectric actuator for two-dimensionally scanning the X-Y stage, a positioning table, disposed below the X-Y stage, for positioning the X-Y stage at an arbitrary position, an objective lens disposed above the X-Y stage, an observation optical system for allowing an operator to observe an enlarged sample image, a measurement optical system, an optical axis of which is aligned with an optical path of the objective lens through a beam splitter, the measurement optical system for emitting a laser beam onto the sample through the objective lens and to receive the laser beam reflected by the sample, a calculator circuit for calculating height information of the sample using an output from the measurement optical system and for obtaining a two-dimensional distribution of the height information, a cover for shielding the X-Y stage, the positioning means, the objective lens, the beam splitter, the obs

Abstract: A photoelectric position encoder using diffraction imagery has a laser light source emitting parallel, coherent light. As least one light sensing device senses the light amount received from the light source and provides an output signal corresponding thereto. A transfer slit plate having periodic slits is disposed between the light source and the light sensing device. The light sensing device thus senses the variation in the received light amount caused by the movement of the transfer slit plate. The light sensing device also senses brightness and darkness fringes of a diffraction image caused by the periodic slits of the transfer plate. Circuitry is coupled to the light sensing device and issues a position signal corresponding to the position of the transfer slit plate.

Abstract: Disclosed herein is a ring laser gyroscope having a non-reciprocal polarization rotation device such as a Faraday rotator configured to provide, through use of a Faraday magnet, a relatively uniform magnetic field across the profile of the Faraday rotator. By providing a uniform magnetic field across the diameter of the Faraday rotator, the magnetic lensing effects are reduced and the thermal sensitivity of the gyroscope's bias is substantially reduced.

Abstract: A manual device for the detection of photometric values on a printed product comprises a measuring head extruding from a housing into a measuring position. The measuring head is mounted together with its optical components on a measuring carriage, which may be displaced along the bottom of the housing by means of a drive motor between a rest position and a measuring position. The drive motor drives via a gear, a drive pulley and a grid axle for a monochromator. A sliding gear and a locking device are coordinated with the drive pulley, with the locking device immobilizing the measuring carriage precisely in the measuring position. The drive motor serves to displace the measuring carriage until the locking process essentially begins; and after this process, serves to rotate the grid axle.

Abstract: The disclosure pertains to a device for the measurement, in a wide range, of a non-reciprocal phase shift generated in a ring interferometer, to a measuring method and, chiefly , to an optic fiber gyrometer. It also concerns a method of measurement, notably a method for the measurement of rotation speed. The disclosure concerns an improvement in a measuring device comprising a phase modulation device enabling the phase to be automatically locked to an interference fringe of the device. The improvement lies mainly in the fact that the light source emits, in the ring, several light frequencies so as to make it possible to remove uncertainty on the order (0, .pi., 2.pi., etc.) of the interference fringe on which the automatic control is achieved. The disclosure can be applied notably to the making of devices for the measurement of angular speeds. The disclosure can be aplied chiefly to the making of optic fiber gyrometers.

Abstract: A method and apparatus for optically detecting transient motion from a scattering surface. A laser beam having a predetermined frequency is directed onto such a surface to thereby scatter the laser beam and produce a scattered laser beam defining an optical wavefront and having an optical spectrum with a central peak at the laser frequency and a sideband on either side of the central peak. The laser beam scattered by the surface is caused to interfere with a reference beam derived from the scattered laser beam and having an optical wavefront substantially matching the wavefront of the scattered beam and an optical spectrum with a single peak at the laser frequency and no sidebands, to obtain an optical signal which is detected and converted into an electrical signal representative of the transient motion.

Abstract: A dimension of an object disposed on a substrate, such as the width of a line of material deposited on a substrate in an integrated circuit manufacturing procedure, is measured by directing a plane wave of electromagnetic energy of predetermined dimensions toward the object at a predetermined angle of incidence. Electromagnetic energy scattered from two predetermined parts or features, such as the edges, of the object are combined so that they produce an interference pattern in space varying between maxima and minima. The characteristics of the interference pattern permit the dimension of the object to be deduced.

Abstract: An apparatus .Iadd.and method .Iaddend.for measuring in a non-contact manner the depth of pits and grooves formed by etching in periodic patterns on the surface of a substrate. The measurement is based on the detection of the intensity of a diffraction ray excluding that of the 0th order through the irradiation of a light beam with variable wave length to the sample. Whereas, the conventional measuring system is sensitive to a diffraction ray of the 0th order, i.e., the major component of the reflected light, that hampers the detection of a higher order diffraction ray carrying information of the depth.