Abstract: A method for measuring ultrashort light pulse which comprises a first step of linear optical filtering of the signal for which it is desired to measure the amplitude of the pulses by means of an acoustic interaction between the optical signal and a colinear or quasi-colinear acoustic beam, a second step of either mixing in a non-linear response electro-optical element of optical beams diffracted by the acoustic beam, followed by one detector for detecting the light intensity derived from the mixer, or effecting one integration detection of the square of the optical intensity diffracted by the acoustic beam.

Abstract: The present invention relates to an apparatus and to a method of load dependent analyzing an optical component (114), comprising the steps of: splitting an initial signal (115) into the reference signal (115b) into and into a measurement signal (115a), intermittently providing a load signal (108) to the component (114), providing the measurement signal (115a), to the component (114),so that the component (114) can influence the measurement signal (115a) to create a signal (120) influenced by and received from the component (114), superimposing the reference signal with the signal (120) received from the component (114), to provide a superimposed signal (118), detecting the superimposed signal (118) when the loading signal (108) is not present at the component (114) to provide an information containing signal (126), and processing the information containing signal (126) to determine an optical property of the component (114) dependent on a property of the load signal (118).

Abstract: The invention is directed to a system and method for implementing process control for paint thickness using sonic NDE techniques. The system may, for example, generate ultrasound waves in a test object during the manufacturing process. A detector such as an interferometer may be used to detect the ultrasound waves. An interpreter or analyzer may determine the thickness and or presence of a defect from the waves. Further, the interpreter may associate the thickness measurement and/or defect with a location about an object. Then, a control system may determine and implement an appropriate control action on the process. The control action may also be associated with the location about the object.

Abstract: The present invention is directed to a heterodyne reflectometer system and method for obtaining highly accurate phase shift information from heterodyned optical signals, from which extremely accurate film depths can be calculated. A linearly polarized light comprised of two linearly polarized components that are orthogonal to each other, with split optical frequencies, is directed toward a film causing one of the optical polarization components to lag behind the other due to an increase in the optical path in the film for that component. A pair of detectors receives the beam reflected from the film layer and produces a measurement signal, and the beam prior to incidence on the film layer and generates a reference signal, respectively. The measurement signal and reference signal are analyzed by a phase detector for phase shift. The detected phase shift is then fed into a thickness calculator for film thickness results.

Abstract: The fiber-optic sensor head (2) for a current or magnetic field sensor comprises an optical fiber which contains a magnetooptically active sensor fiber (3) and at least one polarization-maintaining supply fiber (5), which are optically connected, with the sensor fiber (3) having its fiber protective sheath removed. The sensor head (2) furthermore contains a capillary (6), in which at least the sensor fiber (3) is arranged. Furthermore, the sensor head (2) can be bent in the area of the sensor fiber (3), and a friction reducing means (7) is provided in the capillary (6), in order to reduce the friction between the sensor fiber (3) and the capillary (6). The friction reducing means (7) is advantageously an oil or a dry lubricating means (7). The capillary (6) is advantageously encased by a capillary casing (8). The sensor (2) allows very largely temperature-dependent measurements, is easy to install and allows measurements on large cross-section conductors.

Abstract: A device and a method for wavefront measurement of an optical system (7), in particular by an interferometric measurement technique. A dynamic range correction element (12, 12a) is arranged in the beam path upstream of the detector arrangement (11) and is designed such that the variation in the spatially dependent characteristic of a phase of the wavefront forming the interference pattern is kept below a prescribed limit value throughout a detection area. In addition or as an alternative, a set of several diffraction structures of different period length can be used with a shearing interferometry technique and/or a set of several pairs of a reference pinhole and a signal passage opening with different hole spacings can be used with a point diffraction interferometry technique for different sub-areas of the detection area. A remaining distortion error can be taken into account by determining a corresponding distortion transformation and applying the inverse distortion transformation.

Abstract: An improved confocal microscope system is provided which images sections of tissue utilizing heterodyne detection. The system has a synthesized light source for producing a single beam of light of multiple, different wavelengths using multiple laser sources. The beam from the synthesized light source is split into an imaging beam and a reference beam. The phase of the reference beam is then modulated, while confocal optics scan and focus the imaging beam below the surface of the tissue and collect from the tissue returned light of the imaging beam. The returned light of the imaging beam and the modulated reference beam are combined into a return beam, such that they spatially overlap and interact to produce heterodyne components. The return beam is detected by a photodetector which converts the amplitude of the return beam into electrical signals in accordance with the heterodyne components. The signals are demodulated and processed to produce an image of the tissue section on a display.

Abstract: The invention relates to an apparatus for optical spectroscopy having means to produce an interference pattern and having a spatially resolving detector which can record the interference pattern produced. In accordance with the invention, the wavefronts of at least one of the part rays involved in the interference pattern is influenced in dependence on the wavelength by spectrally dispersive or diffractive optical elements.

Abstract: A method and apparatus for an improved spectral imaging system is provided. The system is capable of measuring the fluorescence, luminescence, or absorption at selected locations on a sample plate. The emissions detection subassembly can tune to any wavelength within a continuum of wavelengths utilizing an interferometric spectral discriminator. The interferometric spectral discriminator creates an interferogram from which the wavelength spectra for each pixel of the array can be calculated, typically using Fourier transform analysis. In one aspect, the chromatic accuracy of the system is calibrated using a calibration slit placed in the input aperture of the input relay lens but outside of the sample image. The slit is illuminated using a source of known wavelength. The fringe count versus the wavelength of the slit illumination source is monitored and used to calibrate the spectral discriminator.

Abstract: Method and apparatus are disclosed that enable lasers to be stabilized in frequency to a high precision while simultaneously enabling rapid re-acquisition of stabilization control loops in the event of frequency locking loss. The principle of operation is to incorporate two etalons, one having a high finesse for frequency high stability, and one having a low finesse for wide error signal locking range, and electronics that pass control between two control systems in such a manner that any loss of frequency locking is rapidly re-acquired.

Abstract: A method and apparatus for wavefront analysis including obtaining a plurality of differently phase changed transformed wavefronts corresponding to a wavefront being analyzed which has an amplitude and a phase, obtaining a plurality of intensity maps of the plurality of phase changed transformed wavefronts and employing the plurality of intensity maps to obtain an output indicating the amplitude and phase of the wavefront being analyzed.

Abstract: A microscope includes a photon source which sequentially generates sets of quantum-mechanically entangled photons including at least two photons, a lens which focuses a set of photons, an actuator which varies a relative distance between a focal position of the lens and a specimen with a minute displacement, a detector detecting photons transmitted through or scattered by the specimen, and a counter counting coincidence detections of n-numbers of photons with the detector during a gating time which is set so that a rate that a number of photons detected during thereof belong to a single set of quantum-mechanically entangled photons exceeds a predetermined rate depending on the varied relative distance.

Abstract: The invention relates to a polarizing beam splitter device, an interferometer module system, a lithographic apparatus, and a device manufacturing method. The polarizing beam splitter device includes an optical element and a polarizing beam splitter layer. The optical element includes a retroreflector surface having three mutually perpendicular faces of high optical quality, a radiation beam passage surface and a handling surface. By designing the optical element, in particular the handling portion, to the shape of a beam splitter element, such as a prism, the handling portion, and thus the polarizing optical beam splitter device etc. itself, may be made more compact and with fewer surfaces to be polished and/or antireflection-coated. The positioning of the parts in a beam splitter is more reliable.

Abstract: A compact monolithic quadrature detector generates four signals from an input beam including orthogonally polarized object and reference beam components provided by an interferometer. The single input beam may be split into four output beams using a first beam splitting interface between two prisms, reflections at two air interface surfaces of the prisms, and a second beam splitting element. Different respective predetermined phase shifts may be imposed on the respective output beams by coatings on the beam splitting surfaces, which impart a different phase shift to the components of a transmitted beam as compared to a reflected beam. The four relatively phase shifted output beams may be directed through polarizers onto respective detectors to provide four signals usable to eliminate many common mode errors and determine the phase difference between the components of the original input beam with high accuracy.

Abstract: The present invention is directed to a device for imaging a gem, and more specifically, a device capable of imaging the fire of a gem and thereby enabling the qualitative assessment of the fire of the gem. The gem imaging device of the present invention includes an exterior assembly and an inner assembly. The exterior assembly includes a viewing system, an outer housing and a base, while the inner assembly includes a view opening, a light baffle, an illumination mechanism, a diffuser plate mechanism, an outer chamber, an inner chamber, a perforated inner compartment and a rotation mechanism. In use, a user images a gem located in the inner assembly of the gem imaging device, and specifically, located within the inner chamber. Based on the light reflected on, into or from the gem, the user may image the gem, and specifically, the fire of the gem.

Abstract: A method of measuring properties of a substrate, the method involving: illuminating a spot on the substrate with a standing wave measurement beam to generate a return measurement beam, the standing wave measurement beam characterized by a standing wave pattern; generating an electrical signal from the return measurement beam; causing the standing wave pattern to be at a succession of different positions on the surface of the substrate; and for each of the succession of different positions of the standing wave pattern, acquiring measurement data from the electrical signal.

Abstract: The structure size of a structure (100) is measured by forming an auxiliary measured value (Dx?, Dy?). A calibration measured value (Px?, Py?) is determined on the basis of a calibration structure (110), which comprises at least two structure elements (140) at a distance from one another, including at least the measured value sum of the width (By?) of one of the two structure elements (140) and the distance (Ay?) between the two structure elements (140). The calibration measured value (Px?, Py?) and a predetermined calibration preset value (Px, Py), which relates to the calibration structure (110), result in the determination of a calibration factor (C, Cx, Cy). The auxiliary measured value (Dx?, Dy?) is corrected using the calibration factor (C, Cx, Cy) in order to form the structure size measured value (Dx,k; Dy,k).

Abstract: An integrated optical sensor, using low coherence interferometry, is capable of determining analyte concentration in a material sample based on absorption, scattering and polarization. The sensor includes one or more light collectors, with each collector having a separation distance from the region where the sample is illuminated by the source. The light backscattered from the sample is combined with reference arm light at the same optical path length for each light collector. The intensity of interference may be correlated with the concentration of an analyte in the material, for example the glucose concentration in a turbid medium like skin. The sensor operation can be based on fiber optics technology, integrated optics, or a combination of these. The operation is such that the spectrally resolved scattering and absorption coefficients can be measured simultaneously. In addition, the operation of the sensor can be synchronized with other sensors, for example temperature, pressure, or heartrate.

Abstract: The invention provides a novel method for absolute fringe order identification in multi-wavelength interferometry based on optimum selection of the wavelengths to be used. A theoretical model of the process is described which allows the process reliability to be quantified. The methodology produces a wavelength selection which is optimum with respect to the minimum number of wavelengths required to achieve a target dynamic measurement range. Conversely, the maximum dynamic range is produced from a given number of optimally selected wavelengths utilized in a sensor. The new concept introduced for optimum wavelength selection is scalable, i.e. from a three wavelength system to a four wavelength system, from four wavelengths to five, etc.

Abstract: In general, in one aspect, the invention features assemblies that include a first polarizing beam splitter positioned in the paths of a pair of initial beams, the polarizing beam splitter being configured to combine the pair of initial beams to form an input beam. The assemblies further include an interferometer positioned to receive the input beam and configured to produce an output beam that includes information about an optical path difference between the paths of two component beams derived from the input beam. A second polarizing beam splitter is positioned in the path of the output beam and configured to split the output beam into a pair of secondary output beams that each include information about the optical path difference between the component beam paths.