Abstract: Disclosed is a system including: (i) an interferometer configured to direct test electromagnetic radiation to a test surface and reference electromagnetic radiation to a reference surface and subsequently combine the electromagnetic radiation to form an interference pattern, the electromagnetic radiation being derived from a common source; (ii) a multi-element detector; and (iii) one or more optics configured to image the interference pattern onto the detector so that different elements of the detector correspond to different illumination angles of the test surface by the test electromagnetic radiation.

Abstract: An apparatus and method for using a counter-propagating signal method for locating events is disclosed. The apparatus and method uses a Mach Zehnder interferometer through which counter-propagating signals can be launched. If the sensing zone of the Mach Zehnder interferometer is disturbed, modified counter-propagating signals are produced and the time difference between receipt of those signals is used to determine the location of the event. A microcontroller receives feedback signals which adjusts polarization controllers so that the polarization states of the counter-propagating signals can be controlled to match the amplitude and/or phase of the output signals. Detectors are provided for detecting the modified signals.

Abstract: A phase-shifting interferometry (PSI) method and corresponding system including: (i) recording an interferogram for each phase in a sequence of phases between test light reflected from a test surface and reference light reflected from a reference surface, the test and reference light being derived from a common source, each interferogram corresponding to an intensity pattern produced by interfering the reflected test light with the reflected reference light, the interferograms defining an interferometry signal for each of different transverse locations of a cavity defined by the test and reference surfaces, each interferometry signal including a series of intensity values corresponding to the sequence of phases, with the difference between each pair of phases in the sequence defining a corresponding phase shift increment; (ii) calculating an initial phase map for the cavity based on at least some of the recorded interferograms; (iii) calculating an estimate for each of at least some of the phase shift increme

Abstract: A single fiber full-field optical coherence tomography (OCT) imaging probe (300) includes a hollow tube (301), and a single fiber (305) disposed within the tube for transmitting light received from a broadband light source to a beam splitter (350) in the tube optically coupled to the single fiber (305). The beam splitter (350) splits the light into a first and a second optical beam, wherein the first beam is optically coupled to a reference arm including a MEMS reference micromirror (335) which provides axial scanning and the second beam is optically coupled to a sample arm for probing a sample to be imaged. Both the reference arm and the sample ami are disposed in the tube. A photodetector array (315) is preferably disposed inside the tube (301) optically coupled to the beam splitter (350). The photodetector array (315) receives a reflected beam from the MEMS reference micromirror (335) and a scattered beam from the sample to form an image of the sample.

Abstract: A semiconductor ring laser gyro includes: a semiconductor laser for emitting light from each end of the gyro; at least one reflection prism comprising a plurality of reflection surfaces for forming an optical circuit, the at least one reflection prism adapted to receive and internally reflect the light emitted from the semiconductor laser; a transmissive mirror disposed at one of the plurality of reflection surfaces of the at least one reflection prism and adapted to transmit part of the light traveling clockwise and part of the light traveling counterclockwise through the optical circuit; and a beam multiplexing prism for multiplexing the light transmitted through the transmissive mirror.

Abstract: A pressure measurement system and method are described. The system uses a tunable laser and a Fabry-Perot sensor with integrated transducer. A detector senses the light modulated by the Fabry-Perot sensor. A signal conditioner, which can be located up to 15 km away, then uses the detector signal to determine the displacement of the diaphragm, which is indicative of pressure exerted against the diaphragm. Use of a temperature sensor to generate a signal, fed to the signal conditioner, to compensate for temperature is also contemplated.

Abstract: Methods for displaying anisotropic properties of an object. The object is illuminated with a first test beam characterized by a first polarization that, after traversing the object, is combined with a reference beam. The combined light of the first transmitted test beam and the reference beam is analyzed by a first pair of polarization analyzers, and interference created between the first transmitted test beam and the reference beam as analyzed by the first pair of analyzers is detected to derive intensity, phase and polarization of the first transmitted test beam. The same is then done with a second test beam that has a polarization with a component orthogonal to the first polarization. Based on the two analyzed beams, complex elements of a Jones matrix associated with the object in a local coordinate system are determined and a plurality of tangible images are displayed that characterize the object based on the complex elements of the Jones matrix.

Abstract: The optical connector includes a holder unit, a first optical fiber fixedly supported by the holder unit and having an inclined end face, a first collimating lens spaced from the inclined end face, a mounting unit supported relative to the holder unit, a second optical fiber disposed opposite the first collimating lens and having an inclined end face, a second collimating lens disposed between the first collimating lens and the second optical fiber and spaced from the inclined end face of the second optical fiber, wherein an optical transmission system comprising the first optical fiber and the first collimating lens is symmetric to an optical transmission system comprising the second optical fiber and the second collimating lens with respect to a plane perpendicular to the optical axis.

Abstract: A compact and stable interferometer is easily built only with fusion splices. The air-holes of a microstructured fiber are intentionally collapsed in the vicinity of the splices and this broadens the propagating optical mode, allowing coupling from core to cladding modes. The transmission spectrum is sinusoidal and of single frequency, indicating predominant interference between the fundamental core mode (7) and a cladding mode (6). A regular interference spectrum can be observed from 650 nm to 1600 nm with fringe visibility reaching 80%. The fringe spacing is inversely proportional to the distance between the splices. This behavior has a significant impact in optical sensing and communications and so the interferometer can be applied for strain sensing. The device comprises two splices (5) of a microstructured optical fiber (1), said splices (5) determining two regions in which the air-holes (4) are collapsed, separated a length (L) along which said two modes are excited.

Abstract: A resonator gyroscope comprises a reference laser generator to produce a reference light; a first slave light source to produce a first slave light locked to the reference light; a second slave light source to produce a second slave light locked to the reference light; a resonator coupled to said first and second light sources, the resonator having first and second counter-propagating directions and resonance tracking electronics coupled to the Sagnac resonator to generate a first beat frequency based on a first resonance frequency for the first counter-propagating direction, a second beat frequency based on a second resonance frequency for the second counter-propagating direction, and a third beat frequency based on a third resonance frequency for the second counter-propagating direction; wherein the rotational rate of the resonator gyroscope is a function of the first, second and third beat frequencies.

Abstract: An alignment interferometer telescope apparatus comprises a coherent laser source, a first beam splitter, a reference spherical mirror, a light source, first and second reticles, and a second beam splitter. At an interference location within the apparatus, a reference laser wave and a test laser wave are allowed to interfere to produce a combined laser wave.

Abstract: An optical fringe generation member control apparatus is provided. The control apparatus includes a detection unit that is configured to detect an optical fringe. Further, the control apparatus includes a control unit that is configured to control operation of a member on which the optical fringe is generated. The control unit controls the operation based on a detection result by the detection unit.

Abstract: Methods, fourier domain optical coherence tomography (FDOCT) interferometers and computer program products are provided for removing undesired artifacts in FDOCT systems using continuous phase modulation. A variable phase delay is introduced between a reference arm and a sample arm of an FDOCT interferometer using continuous phase modulation. Two or more spectral interferograms having different phase delay integration times are generated. The spectral interferograms are combined using signal processing to remove the undesired artifacts. Systems and methods for switching between stepped and continuous phase shifting Fourier domain optical coherence tomography (FDOCT) and polarization-sensitive optical coherence tomography (PSOCT) are also provided herein.

Abstract: A method and system for determining an optimized artificial impedance surface is disclosed. An artificial impedance pattern is calculated on an impedance surface using an optical holographic technique given an assumed surface wave profile and a desired far field radiation pattern. Then, an actual surface wave profile produced on the impedance surface from the artificial impedance pattern, and an actual far field radiation pattern produced by the actual surface wave profile are calculated. An optimized artificial impedance pattern is then calculated by iteratively re-calculating the artificial impedance pattern from the actual surface wave profile and the desired far field radiation pattern. An artificial impedance surface is determined by mapping the optimized artificial impedance pattern onto a representation of a physical surface.

Abstract: A measurement displacement system and method are described. The measurement displacement system comprises a sensor head configured to transmit input optical beams and to receive measurement beams. The system comprises a transmission grating configured to diffract the input optical beams into sub-beams comprising more than one diffraction order. The transmission grating is adapted move in a direction. The measurement displacement system comprises a reflective element configured to diffract the sub-beams from the transmission grating and to return the sub-beams to the transmission grating. The reflective element is substantially stationary relative to the sensor head and the transmission grating selectively recombines the sub-beams to form the measurement beams and returns the measurement beams to the sensor head.

Abstract: A shape measuring apparatus for measuring the shape of a measurement target surface includes an interferometer and computer. The interferometer senses interference light formed by measurement light from the measurement target surface and reference light by a photoelectric converter, while changing the light path length of the measurement light or the reference light. The computer Fourier-transforms a first interference signal sensed by the photoelectric converter to obtain a phase distribution and an amplitude distribution, shapes the amplitude distribution, inversely Fourier-transforms the phase distribution and the shaped amplitude distribution to obtain a second interference signal, and determines the shape of the measurement target surface based on the second interference signal.

Abstract: A gyroscope having photonic crystals for sensing rotation uses the Sagnac effect to determine angular motion. The gyroscope comprises a photonic crystal capable of guiding counter-propagating light beams in a closed path. A light source, coupling, and detection apparatus permits detection of phase changes between the counter-propagating beams, thereby permitting measurement of angular rotation. The photonic crystal comprises a periodic structure of pillars and voids which creates a photonic bandgap waveguide within which light waves in the proper wavelength range propagate with low loss.

Abstract: A system and method for measuring interferences are disclosed. The system is based on the concept of a composite interferometer. The sample is measured while a simultaneous compensation of the phase deviation due to the relative displacement of the optical delay component between the measurements at different pixels of the sample is performed. In the application of profilometry, the information of the surface profile of a material is obtained from the phase shift of the interference signal. By using the proposed compensation mechanism, an axial resolution at nanometer scale can be achieved. For the measurement of a thin film, a polarized probe beam is oblique incident on the sample. The system can perform a simultaneous measurement of the refractive index and the thickness of the thin film. From the ratio of the intensities of the interferograms of TE and TM waves as well as the phase shifts of the interferograms, the refractive index and the thickness of the thin film can then be obtained simultaneously.

Abstract: A color detector includes a light source configured to generate light with a spectrum of wavelengths; a plurality of filters in optical communication with the light source, wherein each filter is configured to pass a bandwidth of wavelengths around a different peak wavelength; and a plurality of photodetectors, each configured to receive light passed through a respective filter of the plurality of filters. The bandwidth of each filter is configured to Correspond to a bandwidth of a curve from a set of standard color matching functions. A method for improving color detection accuracy in a color detector includes matching a bandwidth passed by each of a plurality of color filters with a bandwidth and peak wavelength of a Commission Internationale de l'Eclairage (CIE) color matching function; and separately detecting an amount of light passed by each the filter.

Abstract: A surface reflection encoder scale is used with a surface reflection encoder for detecting a relative movement amount of a member for making a relative move. The surface reflection encoder scale includes a substrate of the member or a substrate provided on the member and a reflection phase grating provided on the substrate and having asperities for changing a phase of reflected diffracted light on its surface. The asperities of the phase grating are formed of a deposition film of metal silicide and chromium.