Abstract: The invention relates to a device for remote measurement of the properties of the atmosphere, more particularly a device used to detect atmospheric turbulence. The device operates on the lidar principle, using the backscattering of a laser beam by the air. The device comprises a laser emission source (1), optical means (5) for collecting a backscattered beam (3) that is backscattered by targets illuminated by the emission source (1), the backscattered beam (3) being substantially centerd about the wavelength of the emission source (1), and means (9) for generating interference fringes (24) resulting from the backscattered beam (3). The device also includes a spatial filter (11) allowing only a central spot of the interference fringes to be seen and, at the center of the spatial filter (11), a mask for blocking off the center of the central spot and more particularly the Mie line of the backscattered beam.

Abstract: A device according to one embodiment of the invention may be applied to measure the overlay (e.g. as a machine performance number) quickly and over an expanded range of locations (possibly everywhere) on a wafer. One method using such a device includes measuring the amplitude of a diffraction order of a diffraction pattern that results from interference between a pattern on wafer level and a pattern that is projected on the pattern on wafer level. The pattern that is projected may be present, for example, at reticle level.

Abstract: Described is a fringe generator for an interferometric measurement system having improved fringe stability and reproducibility. The fringe generator includes a light source at a characteristic wavelength and a diffractive element to generate a pair of diffracted beams from light received from the light source. The fringe generator also includes a lens to receive the pair of diffracted beams and to image the plane of the diffractive element onto an object to be measured. The generated fringe pattern is substantially independent to a change in the position of the light source relative to the lens and a change in the characteristic wavelength of the light source. A broadband light source can be used and the resulting broadband fringe pattern is substantially independent to a change in the position of the light source relative to the lens and to a change in the spectral distribution of the broadband light source.

Abstract: Systems and methods are described for recording multiple spatially-heterodyned direct to digital holograms in one digital image.

Abstract: There are carried out a first measurement operation for measuring the shape of a front surface of a sample held in a held state, a second measurement operation for measuring the shape of a back surface of the sample held in the same state, and a third measurement operation for measuring the shape of the back surface of the sample held so as to cause inverse distortion. First data are acquired on the basis of the front surface shape data obtained through the first measurement operation and the back surface shape data obtained through the second measurement operation. Second data are obtained on the basis of the front surface shape data obtained through the first measurement operation and the back surface shape data obtained through the third measurement operation. Holding distortion is determined on the basis of the first and second data.

Abstract: A method of processing an optical element having a spherical surface comprises providing a first interferometer apparatus having an interferometer optics with an aspherical lens for transforming a beam of a first spherical beam type into a beam of a second spherical beam type, arranging the optical element in a beam path of an incident beam provided by the interferometer optics, interferometrically taking a first measurement of the optical element, and determining first deviations of the spherical surface. The method further comprises arranging the aspherical lens in a beam path of a measuring beam provided by a beam source of a second interferometer apparatus, wherein the measuring beam is one of the first spherical type and the second spherical type, interferometrically taking a second measurement using the measuring beam, and determining second deviations of an aspherical surface of the aspherical lens.

Abstract: An interferometric measuring device for recording shape, roughness or separation distance of the surface of a measuring object, having a modulating interferometer, to which is supplied short coherent radiation by a radiation source, having a measuring probe that is spatially separated from the modulating interferometer and is coupled to it via a light-conducting fiber set-up, in which combined beam components are split in a common arm in a partially transmitting region into measuring and reference beams, and having receiver and evaluating devices for converting the supplied radiation into electrical signals and for evaluating the signals based on phase difference.

Abstract: The present invention integrates the surface plasmon resonance and common-path phase-shift interferometry techniques to develop a microscope for measuring the two-dimensional spatial phase variation caused by biomolecular interactions on a sensing chip without the need for additional labeling. The common-path phase-shift interferometry technique has the advantage of long-term stability, even when subjected to external disturbances. Hence, the developed microscope meets the requirements of the real-time kinetic studies involved in biomolecular interaction analysis. The surface plasmon resonance microscope of the present invention using common-path phase-shift interferometry demonstrates a detection limit of 2×10?7 refractive index change, a long-term phase stability of 2.5×10?4? rms over four hours, and a spatial phase resolution of 10?3 ? with a lateral resolution of 100 ?m.

Abstract: A method and system for providing fast interrogation of a signal received from a fiber optic sensor array using a low drive voltage, by modulating the array signal with a phase generated carrier optical signal having an odd harmonic modulation frequency, sending it to an interferometric system, and demodulating the array signal using a demodulation algorithm that is independent of the phase offset. A detector using direct detection method can be used to determine the signal's phase information. The odd harmonic modulation method allows the selection of a desirable odd harmonic PGC frequency with low drive voltage while providing similar performance of the usual PGC frequency that requires a higher drive voltage.

Abstract: A detector for interferometric distance or displacement measurement. The detector may receive orthogonally polarized object and reference path output beams, which are directed to a polarization-sensitive beam deflecting element. The beam deflecting element deflects one or both orthogonally polarized beams to provide a desired divergence angle between the beams. The diverging beams are input to a mixing polarizer. The beams exiting the mixing polarizer are similarly polarized and therefore interfere. The interfering diverging beams form interference fringes. The spatial phase of the fringes relative to a photodetector array characterizes the phase difference between the object and reference beams of the interferometer.

Abstract: Apparatus and methods are provided for implementing a full width array material scanning spectrophotometer by integrating a Fabry-Perot cavity filter with a silicon photodetector and a light focusing device (an optical guide or a SELFOC® lens). The material to be scanned is illuminated by a broad band illumination source (white LEDs or a fluorescence light source). The Fabry-Perot cavity gap can be tuned electromechanically to get multiple measurements to resolve the spectral distribution of the transmitted light signal. The array spectrophotometric architecture facilitates an elongated, substantially linear band detection and the associated spectral reconstruction technique resolves spectral distribution in the presence of multiple resonant peaks.

Abstract: The present invention relates to a method for determining a qualitative characteristic of an interferometric component (eg a planar waveguide structure) or a process for determining a qualitative characteristic of a stimulus of interest to which the interferometric component (eg the planar waveguide structure) has been exposed by measuring a non-positional characteristic of the interference fringes.

Abstract: Provided are target detection substrate for target detecting apparatuses capable of detecting various targets such as pathogens, biological substances and toxic substances without using a costly measuring apparatus; which can detect these targets with a low measurement error, high efficiency, simplicity, speed and sensitivity; and which can make a quantitative detection thereof. The target detection substrate includes at least a target interaction part which can interact with a target on an optical interference substrate, which optical interference substrate includes a substrate and a different refractive index film having a different refractive index from that of the substrate disposed on the substrate, and interferes irradiated light to radiate it as interference light where the total number of peak tops and peak bottoms in a graph of transmittance against wavelength of the interference light is from 1 to 20 in an arbitrary wavelength range of 100 nm.

Abstract: The invention aims to integrate a two-wave stationary interferometer on a photodetector during fabrication in order to constitute a miniature stationary Fourier transform spectrometer. The interferometer essentially comprises a plate having a first plane face coinciding with an image plane on semiconductor photosensitive elements and a second face that is not parallel to the first face. The second face reflects a wave that has a phase difference relative to the incident wave interfering with it that is a function of the local thickness of the plate.

Abstract: Techniques for compensating for geometric effects of beam misalignment in plane mirror interferometers are disclosed.

Abstract: An optical coherence tomography (OCT) apparatus includes an optical source, an interferometer generating an object beam and a reference beam, a transverse scanner for scanning an object with said object beam, and a processor for generating an OCT image from an OCT signal returned by said interferometer. At least the optical source, the interferometer, and the scanner are mounted on a common translation stage displaceable towards and away from said object. A dynamic focus solution is provided when the scanner and a folded object path are placed on the translation stage.

Abstract: A two-corner retroreflector that includes a common face positioned to receive two beams and two corners each positioned to receive one of the beams and retro-reflect it back through the common face.

Abstract: In general, in a first aspect, the invention features methods that include deriving a first beam and a second beam from an input beam and directing the first and second beams along different paths, where the path of the first beam contacts a measurement object, producing an output beam comprising a phase related to an optical path difference between the different beam paths, determining a position of the measurement object with respect to at least one degree of freedom based on information derived from the output beam, monitoring variations in a direction of the input beam, and using the monitored variations in the direction of the input beam to reduce errors in the determined position associated with deviations of the path of the input beam from a nominal input beam path.

Abstract: A method for determining a characteristic of an analyte in a biological sample, the method comprising: directing broadband light by means of a sensing light path at the biological sample, at a target depth defined by the sensing light path and a reference light path; receiving the broadband light reflected from the biological sample by means of the sensing light path; directing the broadband light by means of the reference light path at a fixed reflecting device; and receiving the broadband light reflected from the fixed reflecting device by means of the reference light path.

Abstract: A phase measuring apparatus for measuring phase characteristics of a film applied onto an object to be measured includes a shearing interference system for providing incident light onto the object or light reflected on the object with shearing interference, a detector for detecting shearing interference information, and a computing unit for calculating the phase characteristics of the film based on the shearing interference information.