Abstract: To measure a sum of electrical currents in different conductors, light is led in an optical sensing fiber around all the conductors. The sensing fiber can be wound around the conductors in a single loop or in several individual loops. Interspersed polarization maintaining fibers and retarders can be used to transfer the light between individual loops for preventing undesired signals from stray magnetic fields. The method has high accuracy is particularly suited for measuring large currents that sum up to zero.

Abstract: A system for evaluation of optical quality of an optical device includes a light source configured to generate light, the generated light be received by an optical device. An interferometric lens apparatus is removably mounted to the optical device to generate interference fringes. A camera device is configured to receive and display the interference fringes, and a computer configured to analyze the interference fringes received from the camera device to determine aberrations of the optical device and generate a recommendation to correct the determined aberrations. Methods for evaluating the optical quality of an optical device are also described.

Abstract: An interferometer of the invention includes: a first splitting element which includes a first transparent medium and a first splitting film formed on the first transparent medium, and which splits incident light into a first split beam and a second split beam, the first split beam being the incident light reflected by the first splitting element and the second split beam being the incident light transmitted through the first splitting element; and a second splitting element which includes a second transparent medium and a second splitting film formed on the second transparent medium, and which causes interference between the first split beam and the second split beam passed through different optical paths, the second splitting element being positioned such that a positional relationship between the second transparent medium and the second splitting film with respect to a direction of incidence on the second splitting element of the first split beam is opposite to a positional relationship between the first tr

Abstract: A positioning apparatus comprises a first measuring device measuring a position of the stage in a first measuring range, a second measuring device measuring a position of the stage in a second measuring range having an overlapping range overlapping the first measuring range, a third measuring device measuring a position of the stage in the overlapping range, and a controller controlling the first measuring device to take over the measurement value obtained by the second measuring device in the overlapping range in moving the stage from the second measuring range to the first measuring range, thereby switching from measurement by the second measuring device to measurement by the first measuring device. The controller performs correction processing based on the measurement by the third measuring device so as to reduce an error of the measurement value obtained by the first measuring device after the switching.

Abstract: An optical image measuring device forms an image of an object to be measured based on a result of light-receiving by a light-receiving part. This optical image measuring device comprises: a specifying part configured to specify the light irradiated state to the light-receiving surface of a light-receiving part via a light guiding part and a dispersion part; and an altering part configured to alter the relative position and/or direction between a light-receiving surface and the exit end of light from the light guiding part, based on the light irradiated state.

Abstract: In a method and a system for generating images a laser being tuneable at a rapid frequency and a corresponding synchronized detector are provided. In a preferred embodiment the tuneable laser and the detector are synchronized in time so that the wavelength from the tuneable laser is known when the detector is given its detected signal value. In accordance with another preferred embodiment the tuneable laser is a monolithic laser, and in yet another preferred embodiment the laser and the detector are located on a common chip module. The system can be used to generate OCT images.

Abstract: A method of manufacturing an optical element (5) comprises testing an optical surface (3) of the optical element, using an interferometer 1a directing measuring light (23a) onto the optical surface wherein the measuring light traverses two successive holograms (44, 48) disposed in the beam path of the measuring light upstream of the optical surface.

Abstract: The invention represents an improved method of measuring trenches on semiconductor wafers with optical spectroscopy. According to the described method, it is possible to characterize not only depth but also shape of the trench. The advancement is achieved by improved Effective Medium Approximation-based modeling of the optical response of trench structures.

Abstract: A method of and system for correcting mode hop wavelength error in data obtained measuring optical characteristics over a number of wavelengths, includes at a location where mode hop wavelength error occurs in an assemblage of data, representing optical characteristics with respect to wavelength of incident electromagnetic energy of a device under test, compensating or correcting the data to overcome errors due to mode hop occurring in the measurement process.

Abstract: A method for determining a change in a position of a support is described. The method includes determining the change in the position of the support used in an imaging system, where determining the change includes computing the position by operating a photodetector configured to detect laser energy that provides information regarding the position.

Abstract: A method and a system for analyzing the wavefront of a light beam, wherein a diffraction grating is arranged in a plane perpendicular to the light beam to be analyzed and optically conjugated to the analysis plane. Different emerging beams of the grating interfere to generate an image having deformations linked to the gradients of the wavefront to be analyzed. The method is characterized in that the grating carries out the multiplication of an intensity function which is implemented by a two-dimensional grating with hexagonal meshing of surface S transmitting the light of the beam to be analyzed into plural emerging beams arranged in a hexagonal meshing, by an phase function which is implemented by a two-dimensional grating with hexagonal meshing of surface 3S which introduces a phase shift close to 2?/3 (modulo 2?) between two adjacent secondary beams.

Abstract: In general, in a first aspect, the invention features a method that includes using an interferometry assembly to provide three different output beams, each output beam including an interferometric phase related to an optical path difference between a corresponding first beam and a corresponding second beam, each first beam contacting a measurement object at least once, monitoring the interferometric phases for each of the three different output beams, and deriving information about variations in the optical properties of a gas in the first beam paths from the three monitored phases.

Abstract: A microstructural feature and material property monitoring device for a metallic material that can easily adjust relative position between an irradiation position of laser beams applied to the metallic material to propagate pulsed ultrasonic waves in the metallic material and detection position of a laser interferometer, and therefore can accurately monitor the microstructural feature and material property of the metallic material. The device relatively moves the irradiation position of the laser beams generated by a laser oscillator and the detection position of the laser interferometer. The irradiation position of the laser beams generated from a laser oscillator and the detection position of the laser interferometer are controlled to be aligned with a relative position according to the microstructural feature and material property of the metallic material based on the time from the transmission of the pulsed ultrasonic waves to the detection by the laser interferometer.

Abstract: Provided are common path frequency domain and time domain OCT systems and methods that use non-specular reference reflection for obtaining internal depth profiles and depth resolved images of samples. Further provided is a delivering device for optical radiation, preferably implemented as an optical fiber probe with a partially optically transparent non-specular reflector placed in the vicinity of an associated sample. High frequency fringes are substantially reduced and a stable power level of the reference reflection is provided over the lateral scanning range. The partially optically transparent non-specular reflector is implemented as a coating placed on the interior surface of the optical probe window including spots of a metal, or a dielectric coating, separated by elements of another coating or just spaces of a clean substrate. In an alternative embodiment, the scattering elements are made 3-dimensional, having, for example, a spherical shape.

Abstract: The disclosure features multiple degree-of-freedom interferometers (e.g., non-dispersive interferometers) for monitoring linear and angular (e.g., pitch and/or yaw) displacements of a measurement object with compensation for variations in the optical properties of a gas in the interferometer measurement (and/or reference) beam paths. The disclosure also features interferometry systems that feature an array of interferometers (e.g., including one or more multiple degree-of-freedom interferometer), each configured to provide different information about variations in the optical properties of the gas in the system. Multiple degree-of-freedom interferometers are also referred to as multi-axis interferometers.

Abstract: An interferential spectroscopy detector including a waveguide having an input side and a mirror on an opposite side, and means for detecting electromagnetic rays delivering an electric signal as a function of local intensity of an electromagnetic wave, detection being produced between an input side and the mirror.

Abstract: The present invention provides a microscopy method and a microscope, which enable microscopic observation of desired information of a specimen with an extremely high S/N ratio in a short period of time without increasing intensity of a light sources. The method of the invention is characterized in that it comprises: a simultaneous irradiation step of irradiating a specimen with first and second electromagnetic rays having different wave length with the rays overlapping at least partly each other; and a simultaneous irradiation visualization step of visualizing a spatial distribution of a refractive index variation caused by the irradiation of the first electromagnetic ray as a phase contrast image of the second electromagnetic ray having passed through the specimen in the region of the specimen to which the overlapped the first and the second electromagnetic rays are irradiated.

Abstract: A fixed-point detector is provided. The fixed-point detector includes a plurality of fixed-point detecting patterns, a fixed-point detecting light source, and a plurality of photoelectric conversion elements. The plurality of fixed-point detecting patterns each have a pair of diffraction gratings for diffracting incident light in different directions. The fixed-point detecting light source irradiates the pair of diffraction gratings with light while moving in the measurement-axis direction with respect to the plurality of fixed-point detecting patterns. The plurality of photoelectric conversion elements move together with the fixed-point detecting light source, while receiving light beams diffracted by the respective diffraction gratings of the plurality of fixed-point detecting patterns and converting the diffracted light beams into electric signals.

Abstract: An interferometer for optically measuring an object (10), including a light source (1), at least one beam splitter (2) and at least one detector (12a, 12b), with the beam splitter being arranged in the beam path of the light source such that a light beam created by the light source is split into a working beam (3) and a reference beam (4). The interferometer is embodied such that the working beam impinges on the object (10) to be measured and the working beam is at least partially reflected by the object and interfered with the reference beam on the detector (12a, 12b).

Abstract: An interferometric-spatial-phase imaging (ISPI) system includes a substrate wafer. An alignment configuration is permanently embedded in the substrate wafer. The alignment configuration uses a global coordinate reference system by providing a plurality of global reference marks that encompass up to the entire substrate wafer. A plurality of alignment markings is provided on a surface in close proximity to the alignment configuration for obtaining continuous six-axis control of a scanning probe tip with respect to the global coordinate reference system.