Abstract: A device for driving a mirror of a laser cavity has a deflectable body which matches the mirror in coefficient of thermal expansion and acts in response to forces from one or more piezoelectric elements. The piezoelectric elements deflect a membrane of the driver body which acts on the mirror in an axial direction to control the path length of the cavity. In a preferred embodiment, the driver body is made of a low expansion glass-ceramic or fused quartz material and has a peripheral ring and an inner hub for transfer of deflection forces to the mirror in either of two opposite directions.

Abstract: A rotation rate readout method employing a passive optical resonator. The ring resonator is operated at approximate resonance in reflection and rotation rate-dependent phase shifts are detected, in particular as first harmonics, in the resonator. Two partial light beams are first frequency shifted by equal and opposite amounts, such frequency shift being modulated. Light components coupled out of the resonator pass through a mode filter in the opposite direction and are detected as an interference signal by an opto-electronic converter. The latter signal is demodulated with respect to the modulation frequency or its harmonics and the rotation rate signal obtained therefrom. Self-compensation of the optical and electronic readout systems may be attained by periodic brief and strong damping of the ring resonator.

Abstract: A detection system is provided which has a very wide linear dynamic range (for a typical laser, fifteen orders of magnitude), as well as a high sensitivity (shot noise limited), high angular resolution (diffraction limited), and which is also polarization resolving. The apparatus is used for measuring optical power, and includes a system for producing two optical beams such that at some point and thereafter along an optical path of the beams, a frequency difference exists between the two beams, with one of the two beams having a known or constant optical power, and the other of the two beams being the beam whose power is to be measured. Also included is a combining element for coherently combining the two optical beams.

Abstract: Apparatus for producing a three phase signal from two or three optical beams at different optical frequencies, such signal having a frequency equal to the difference frequency or frequencies between the optical frequencies of said beams including, preferably, an equal energy single mode fiber optic coupler and optical focusing means, such as gradient index rods, for directing said light beams onto light conducting fibers, preferably single mode fibers, thence through the coupler, thence onto light detectors to produce a substantially balanced three phase electrical signal at said difference frequency or frequencies.In a preferred embodiment, the light beams are two in number, connected to only two input ports of said coupler, and the light beam sources are the output beams of counter- propagating ring laser beams in a ring laser gyro.

Abstract: A three-axis fiber-optic interferometer as applicable in particular to a gyrometer comprises three optical fibers forming rings disposed along three different axes. The three optical fibers are fed by a light beam emitted by a single source. A single interference photodetector receives the light beam after transit through the different fibers. Coupling devices couple the second fiber to the first fiber and the third fiber to the second fiber.

Abstract: The invention comprises an interferometric load sensor, or force balance 10 which utilizes etalons 12, 14 to form a reflective cavity 16. A fringe pattern is formed in cavity 16 by light from laser source 26. One of the etalons (14) is mounted to a section 20 that is sensitive to the application of a force 22. Flexing of cantilever 24 due to application of force 22 on section 20 changes the air gap wedge angle between the etalons 12, 14 and thereby shifts the fringe field formed in cavity 16. The shift in the fringe field is observed by light detectors 30, 32.

Abstract: In a method for measuring the flowing of the material, the following steps: forming an array of parallel strips of said material constituting a diffraction grating; submitting said grating at the same conditions as the material, the flowing of which is to be monitored; illuminating the grating by a single wavelength light beam and observing the diffracted light.

Abstract: A spectrometer construction is shown in which the chassis of the spectrometer is fabricated by stamping, punching, and bending sheet metal. The mirror supports and other elements are also formed from sheet metal. Precision locations are assured by tab and slot, or half-shear and recess, matching of the sheet metal parts. The mirrors in the spectrometer (other than those in the interferometer) are secured directly to vertical sheet-metal walls without intervening adjustments. The mirrors have unitary reflection and backing structures formed either by a diamond-cutting lathe, or by precision plastic molding. The same mirror locating means are used both during formation of each curved mirror surface and also in assembling of the mirror body in the spectrometer.

Abstract: A portion of each of the pair of counter-propagating laser beams in a ring laser cavity are extracted and redirected back into the cavity with servo controlled phase and amplitude. The phase and amplitude of one of the redirected beams is a function of a common first discriminant signal but independently controlled, and the phase and the amplitude of the second redirected beam is responsive to a second mutually exclusive discriminant signal and independently controlled. The redirected beams are such as to minimize the internal back scattering effects within the ring laser cavity.

Abstract: A two source passive ring resonator gyroscope having a single piece body with integral first, second and third resonator cavities. A first laser means uses the first resonator cavity to provide a first single frequency light source. A second laser uses the second resonator for a second laser to provide a second single frequency light source. The third resonator cavity is a passive high Q evacuated cavity having a closed optical path tuned to resonate at substantially the light frequency of the first and second resonator cavities. The first signal frequency light source is split into a propagating light source and a first reference frequency light source. The propagating source is coupled into the third resonator cavity to form a propagating light beam. The second single frequency light source is split into a second frequency light source and into a second reference frequency light source.

Abstract: A bottle is moved over a sector of a circular path and simultaneously rotated around its longitudinal axis for the opto-electronic inspection of the mouth area for chipping of the glass. The bottle is guided through the beam path of a measuring apparatus on its way over the circular path. A measuring beam passes at an oblique angle to the longitudinal axis of the bottle in the area of the mouth opening. The location dependent scanning signal generated by the measuring apparatus during each scan corresponding to every discrete angular position of the bottle displays a characteristic intensity modulation. The presence of a chip in the glass may be recognized in the scanning signal by the absence of the intensity maximum present at the location of a chip. The absence of the intensity maximum may be ascertained by measuring the distance between two adjacent intensity maxima and comparing the measured distance with a reference value.

Abstract: A differential plane mirror interferometer comprises a source (10) which emits a light beam containing two orthogonally polarized components of different frequencies; a source of a stabilized electrical reference signal (11) of a frequency corresponding to a difference frequency between the two components of the light beam; a beamsplitter/beam folder assembly (16, 16A) for converting the input beam into two separated, parallel, orthogonally polarized beams; a half-wave retardation plate (29A, 29) located in one of the separated beams to produce two separated parallel beams with the same polarization; means including a polarizing beamsplitter (44), for causing each of the separated parallel beams with the same polarization to be reflected twice by one of two plane mirrors (71, 70) to produce two parallel output beams with the same polarization; a half-wave retardation plate (29B, 29) located in one of the separated parallel output beams, with the beamsplitter/beam folder assembly (16, 16B) converting the two s

Abstract: In the present invention, the output signal of a dithered ring laser angular rate sensor and a signal representative of the resultant dithering of the sensor, are each independently signal analyzed to obtain the frequency components contained in such signals. Data pairs of frequency components of the same frequency are signal processed in a manner to derive a compensation or correction signal representative of the dither frequency component in the readout. In turn, the correction signal is subtracted from the readout signal to provide a corrected readout signal substantially devoid of any dither signal component.

Abstract: The device consists essentially of a frame designed to support the hologram, at least one source of electromagnetic radiation, at least one sensor and a processing unit which, in at least one predetermined relative position assumed by the aforesaid frame, source and sensor, verifies that the electrical signals emitted by the sensor and dependent upon the radiation associated with a portion of the reconstructed image of the hologram correspond to electrical signals previously stored in the memory of the processing unit.

Abstract: A differential plane mirror interferometer comprises a source (10) which emits a light beam containing two linear orthogonally polarized components; a beamsplitter/beam folder assembly (16, 16A) for converting the input beam into two separated, parallel, orthogonally polarized beams; a half-wave retardation plate (29A, 29) located in one of the separated beams to produce two separated parallel beams with the same polarization; means including a polarizing beamsplitter (44), for causing each of the separated parallel beams with the same polarization to be reflected twice by one of two plane mirrors (71, 70) to produce two parallel output beams with the same polarization; a half-wave retardation plate (29B, 29) located in one of the separated parallel output beams, with the beamsplitter/beam folder assembly (16, 16B) converting the two separated parallel orthogonally polarized output beams into a single output beam in which the phase difference between the two polarization components of the single output beam i

Abstract: A color separation device or chamber in the form of a regular rhombic dodecahedron. Each interior face or plane comprises a specifically colored reflecting surface and is arranged in such a manner that each interior plane expresses the given order of reflection suggested by a syllogistic algorithm. The conventional or regular dodecahedron is circumscribed by a sphere. The chamber is suitable as a cell for liquid or gas in an analysis instrument such as a spectrophotometer. Such a chamber may be equipped with inlet and outlet ports, light sources and light sensors at appropriate locations in the interior faces.

Abstract: A plurality of interference beams are obtained by making a pair of beams of reference and test-sample light diverge into a plurality of optical paths; providing phase difference between reference and test-sample beams constituting each of a plurality of pairs of reference and test-sample beams having traveled on the plurality of optical paths. The plurality of interference beams are respectively received by light receiving means such as image pickup elements, and the phase difference between the beams of reference and test-sample light is obtained on the basis of signals relating to the plurality of interference beams supplied from the light receiving means, thus obtaining the state of a wave surface of the test-sample beam.

Abstract: A ring loser gyroscope for sensing rotations about three orthogonal axes. A frame includes and internal arrangement of three intersecting cavities, each of which is arranged for measuring rotation about one of the orthogonal axes. Each cavity comprises a non-planar arrangement of four cavity legs. A pair of anodes and a cathode cooperate with the intersecting cavities and, in one embodiment, with bypass tubes, whereby undesired Fresnel-Frizeau phase shifts are eliminated by gas flow effect cancellations.

Abstract: A color reference standard and method of making same are disclosed. A transparent film having a matte surface and a spectral optical modulator are selected. The spectral optical modulator, preferably a glossy pigment, is coated onto the film surface opposite the matte surface, as by painting, hand drawn down, or silk screen application. So configured, the color reference standard provides a matte color reference standard when the glossy pigment coating is viewed through the matte film surface and a glossy reference standard when the glossy pigment is viewed directly from the opposite side of the reference standard. Advantageously, both the matte and glossy reference surfaces are cleanable without altering the reflectance values of the color standard.

Abstract: A path length control for a ring laser is described which captures a true peak power laser mode in the presence of parasitic secondary power modes. The control utilizes a decaying dither of the optical path length which decays from a large initial dither amplitude.