Abstract: A light-emitting apparatus, for enabling a beam of light to be projected on a desired target located a distance away to project the beam on the desired target without any or substantially any undesired movement. The apparatus may include a housing, a light generating device located within the housing and operable to generate a beam of light, a sensing device or devices for sensing an undesired action of the housing, a control circuit operable to provide a control signal corresponding to the sensed undesired action, and a drive device operable to counter act all or at least some of the undesired action of said housing in accordance with said control signal. The sensing device or devices may be one or more gyroscopes, accelerometers or other such devices.

Abstract: An arrangement for generating phase-shifted incremental signals characterizing relative positions of two objects moving with respect to each other along a measuring direction. The measuring arrangement includes a light source emitting bundles of beams, a measurement grating, a plurality of optional gratings and a scanning unit. The scanning unit includes a grating in a scanning plane, wherein the grating includes a plurality of blocks arranged periodically along the measuring direction with a grating periodicity equaling a fringe pattern periodicity, and each block includes n grating sections arranged along the measuring direction, each of the n grating sections having a periodic grating structure, deflecting the bundles of beams propagated through each of the n grating sections in several different spatial directions.

Abstract: Apparatus and method for increasing the sensitivity in the detection of optical coherence tomography and low coherence interferometry (“LCI”) signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source is split into N spectral bands. The N spectral bands are individually detected and processed to provide an increase in the signal-to-noise ratio by a factor of N. Each spectral band is detected by a separate photo detector and amplified. For each spectral band the signal is band pass filtered around the signal band by analog electronics and digitized, or, alternatively, the signal may be digitized and band pass filtered in software. As a consequence, the shot noise contribution to the signal is reduced by a factor equal to the number of spectral bands. The signal remains the same. The reduction of the shot noise increases the dynamic range and sensitivity of the system.

Abstract: A double-biprism electron interferometer is an optical system which dramatically increases the degree of freedom of a conventional one-stage electron interferometer. The double biprism interferometer, however, is the same as the optical system of the single electron biprism in terms of the one-dimensional shape of an electron hologram formed by filament electrodes, the direction of an interference area, and the azimuth of the interference fringes. In other words, the longitudinal direction of the interference area is determined corresponding to the direction of the filament electrodes, and the azimuth of the interference fringes only coincides with and is in parallel with the longitudinal direction of the interference area.

Abstract: A tilting angle measuring device includes an optical device, a four-quadrant optical detector and a computing unit. By the optical device, a light beam emitted by the coherent light source is processed into a reference beam and a test beam. The four-quadrant optical detector has four photoelectric converting units arranged in an array for respectively receiving the reference and test beams. The computing unit is electrically connected to the four-quadrant optical detector for computing a tilting angle of the object with respect to a predetermined position according to four intensity values of the test beam.

Abstract: A device and a method for suppressing 2nd order harmonic distortion in a Resonator Fiber Optic Gyroscope includes driving a laser to generate at least one of a plurality of counter propagating laser beams traveling through a fiber optic resonator according to a modulated signal. The modulated signal can be represented by a polynomial having two terms, and each of the two terms is suitably multiplied by a coefficient and a constant. A modulation amplitude adjuster amplifies the modulation signal by an amplification factor as it is used to drive the laser. When the amplification factor is suitably chosen to represent a square root of a ratio of the constants, the total harmonic distortion in the RFOG is minimized.

Abstract: An apparatus for determining a polarization-insensitive interferometric signal and a birefringence for a sample and methods for using such an apparatus to characterize the sample are proved herein. Such apparatuses may generally be designed to eliminate birefringence associated with the apparatus itself, collect data from the sample using light in both orthogonal states, and determine the interference birefringence associated with the collected data.

Abstract: An optical sampler with high temporal resolution comprises a TOAD device with a loop optical path at the inlet of which is input an optical signal to be sampled and along which path is arranged a point of input of an optical control signal produced by a source and appropriately delayed by a delay line to change on command the temporal position of the TOAD transmittance window compared to the signal to be sampled. In the loop there is also a nonlinear device. The sampler includes a controller to command the delay line to move step by step the transmittance window and make it run on the signal to be sampled. The mean power transmitted at the TOAD output is measured for each window position and a derivative on the mean powers found for each window position is performed, thus finding samples representing the optical signal.

Abstract: To measure a hollow three-dimensional object without contact, this object being translucent or transparent vis-á-vis a visible light, an image of the object is acquired by single-view backlit shadowgraphy, along a viewing axis, by observing this object with visible light, this image comprising at least one luminous line, an equation is established that connects at least one optogeometric parameter of the object to at least one geometric parameter of the luminous line, this geometric parameter is determined, and the optogeometric parameter is determined by means of the equation and the geometric parameter thus determined.

Abstract: Sinusoidal in-phase and in-quadrature signals at a given spatial frequency are combined with the irradiance signals generating a correlogram of interest and integrated over the length of the correlogram data-acquisition scan. The integration outputs are then used to calculate the amplitude and the phase of the correlogram signal at the selected spatial frequency, thereby producing targeted spectral information. The signal generator used to generate the in-phase and in-quadrature sinusoidal signals may be scanned advantageously through any desired range of spatial frequencies, thereby producing corresponding amplitude and phase spectral information for the correlogram. Because the procedure produces spectral information independently of the number of data frames acquired during the interferometric scan, it is materially more rapid than conventional FFT analysis.

Abstract: An apparatus and a method for detecting surface motion of an object subject to ultrasound are disclosed. The method comprises generating a laser beam, dividing the laser beam into a reference beam and an object beam to be directed onto the surface, thereby producing a scattered object beam, introducing a frequency shift between the reference beam and the scattered object beam, wherein the frequency shift is smaller than the ultrasonic frequency, detecting the interference between the scattered object beam and the frequency shifted reference beam using a plurality of detecting elements to generate a plurality of electrical interference signals, wherein the electrical interference signals each comprise a wanted signal component indicative of the surface motion and a noise signal component, and processing the electrical interference signals to determine the surface motion of the object.

Abstract: A system for detecting piston diversity between mirror segments. The system includes a pupil plane mask, a transform optical element, and an image detector. The pupil plane mask includes two or more open mask areas and two or more polarizers. Each polarizer is disposed within a respective one of the open mask areas. A first one of the two or more polarizers has a first polarization orientation, and a second of the two or more polarizers has a second polarization orientation.

Abstract: Methods and systems for using common-path interferometry are described. In some embodiments, a common-path interferometry system for the detection of defects in a sample is described. An illumination source generates and directs coherent light toward the sample. An optical imaging system collects light reflected from the sample including a scattered component of that is predominantly scattered by the sample, and a specular component that is predominantly undiffracted by the sample. A variable phase controlling system is used to adjust the relative phase of the scattered component and the specular component so as to improve the ability to detect defects in the sample.

Abstract: A method, implementable in a resonator fiber optic gyroscope (RFOG) having a first wave generator configured to produce a first resonance-detection modulating signal at a fundamental resonance frequency, includes generating with at least a second wave generator a second modulating signal at an even harmonic of the first modulating signal. The second signal is amplitude-modulated (AM) at a frequency that is harmonically unrelated to the first signal. The first signal is added to the second signal with a summing element to produce a resonator output bias error signal. An optimum amplitude is determined from the error signal. Subsequently, the amplitude of the first signal is controlled to the optimum amplitude.

Abstract: Disclosed herein is an apparatus for measuring the shape of a 3D object using an interferometer. The apparatus includes a light source unit, a beam splitter, a reference mirror, an actuator, an image pickup device, and a control unit. The light source unit emits light. The beam splitter divides the light from the light source unit. The reference mirror reflects light as a reference beam. The actuator moves the reference mirror. The image pickup device acquires a plurality of interference patterns by causing the reflected beam and the reference beam to interfere with each other. The control unit measures the shape of the object from the acquired interference patterns, outputs reference mirror drive signals to the actuator, and issues an image capture command at the end of image capture time that is shorter than settling time.

Abstract: Systems, arrangements and methods for obtaining three-dimensional imaging data are provided. For example, a broadband light source can provide a particular radiation. A first electro-magnetic radiation can be focused and diffracted, and then provided to at least one sample to generate a spectrally-encoded line. A second electro-magnetic radiation may be provided to a reference, which may include a double-pass rapidly-scanning optical delay, where the first and second electro-magnetic radiations can be based on the particular radiation. An interference between a third electro-magnetic radiation (associated with the first electro-magnetic radiation) and a fourth electro-magnetic radiation (associated with the second electro-magnetic radiation) can be detected. The spectrally-encoded line may be scanned over the sample in a direction approximately perpendicular to the line. Image data containing three-dimensional information can then be obtained based on the interference.

Abstract: A vibration-resistant interferometric scanning system and method are provided in the present invention. In the present invention, the brightness distribution in a high-coherence interference pattern is analyzed so as to perform a compensation action to lock the brightness distribution of a high-coherence interference pattern and consequently locking the fringe distribution of a low-coherence interference pattern or to perform a scanning operation composed of plural shifting actions with specified scanning distances in sequence and plural compensation actions to lock the fringe distribution in a low-coherence interference pattern corresponding to the surface profile of a measured object. Consequently, with the system and method of the present invention, the surface profile of a measured object disturbed by external or internal vibrations can be measured accurately and precisely.

Abstract: To achieve an apparatus capable of measuring a light absorption coefficient f a sample with high sensitivity. A ring down spectroscope uses a wavelength-variable femtosecond soliton pulse light source 1. Pulse light is input to a loop optical fiber 6 through a first light waveguide 4 and a wavelength selective switch 5. Ring down pulse light is input to a homodyne detector through the wavelength selective switch 5. On the other hand, pulse light propagating in the first light waveguide 4 is split and input to light waveguides constituting a second light waveguide 20 through an optical directional coupler 8 and a first optical switching element 12. The pulse light propagating in the second light waveguide 20 is input to the homodyne detector as reference light and used for synchronous detection. The plural light waveguides constituting the second light waveguide 20 differ in optical length in accordance with the length of the optical fiber 6, and can slightly change the optical length.

Abstract: The invention relates to a structure characterising device comprising means which are used for generating a first pump radiation and a second probe radiation and for transmitting different wavelength radiation, means for producing a time offset between said first pump and second probe radiation on the structure by means of detecting means of said second beam after the reflection or transmission thereof to said structure in such a way that an analysis signal is generated, means for processing said signal and identifying an area corresponding to the signal jump, for determining the jump amplitude according to different wavelengths, for comparing said amplitude with a theoretical amplitude variation pattern according to the wavelengths and for determining, for the wavelength characteristic for said theoretical pattern, a characteristic value associated to the structure thickness and to the radiation propagation velocity in said structure.

Abstract: Interferometers and autocorrelator based sensors are disclosed that are configured to have multiple sample arms which can be scanned and the backscattered low coherence source light from a sample resolved in a single sweep of one or more variable delays of the sensor. Borescopes and catheters capable of scanning multiple sections or areas of materials and tissues using these sensors are described.