Class / Patent application number | Description | Number of patent applications / Date published |
356484000 | Having light beams of different frequencies (e.g., heterodyning) | 72 |
20080204760 | Swept wavelength imaging optical interrogation system and method for using same - A swept wavelength imaging optical interrogation system and a method for using the same to interrogate one or more biosensors are described herein. The swept wavelength imaging optical interrogation system is built upon a swept wavelength optical interrogation technology where a 2-D label free image is extracted from a series of high speed spectral images of the biosensor(s) without the need of performing mechanical scanning. | 08-28-2008 |
20080231860 | Optical Device and Method for Sensing Multiphase Flow - A method for measuring the velocity of a multiphase fluid flowing in a pipe. The method comprises directing at least two collimated beams of light from an illuminator through the multiphase fluid by transparent portions of the pipe. The at least two collimated beams are spaced apart in a direction of flow of the multiphase fluid by a predetermined distance. The method also includes detecting scattered, deflected and attenuated light with at least two photodetectors to produce at least two signals. The at least two photodetectors are associated with the at least two collimated beams. The method also includes calculating a cross-correlation function between the at least two signals to determine a time delay between the signals and calculating the average velocity of the multiphase fluid by taking the ratio of the predetermined distance to the time delay. | 09-25-2008 |
20080297806 | APPARATUS AND METHOD FOR CONTROLLING RANGING DEPTH IN OPTICAL FREQUENCY DOMAIN IMAGING - Exemplary embodiments of an apparatus are provided. For example, the exemplary apparatus can include at least one first arrangement providing at least one first electro-magnetic radiation to a sample, at least one second electro-magnetic radiation to a first reference and at least one third electro-magnetic radiation to a second reference. A frequency of radiation provided by the first arrangement generally varies over time. The exemplary apparatus may also include at least one second arrangement which is configured to detect a first interference between at least one fourth electro-magnetic radiation associated with the first electro-magnetic radiation and at least one fifth electro-magnetic radiation associated with the second radiation. The second arrangement is also configured to detect a second interference between at least one sixth electro-magnetic radiation associated with the first electro-magnetic radiation and at least one seventh electro-magnetic radiation associated with the third radiation. | 12-04-2008 |
20090021746 | TOMOGRAPHY APPARATUS - In a tomograpy apparatus: low-coherence laser light is split into measurement light and reference light; the frequency of the reference light is slightly shifted from the frequency of reflected light generated by reflection of the measurement light by a sample; the reference light is optically combined with the reflected light; interference light generated by interference of the reference light with the reflected light when the reference light is combined with the reflected light is detected: fluorescence emitted by excitation of a fluorescent dye or a fluorescent pigment in the sample when the sample is irradiated with the measurement light is detected: a first tomographic image of the sample is formed by the detected interference light, and a second tomographic image of the sample is formed by the detected fluorescence. | 01-22-2009 |
20090027686 | Optical heterodyne fourier transform interferometer - An interferometer and method for interferometric analysis are provided. The methodology includes generating first and second light beams from a light source, interacting the first light beam with an object under inspection, forming, from light emanating from the object under inspection in response to the interacting, an image of the light source on an image sensor, projecting the second light beam on the image on the image sensor, the combination of the light emanating from the object under inspection and the second light beam forming a collective image on the image sensor, applying a Fourier transform to the collective image formed on the image sensor, thereby forming a phase image, and isolating a wavefront map of the object under inspection from within the phase image. | 01-29-2009 |
20090046296 | FIBER-OPTIC HETERODYNE IMAGING VIBROMETER - A method and system for performing two-dimensional laser Doppler vibrometry (LDV) are disclosed. A high speed fiber optic heterodyne imaging vibrometer can be used for the imaging of high speed surface deformation and/or vibration. Images provided by the high speed fiber optic heterodyne imaging vibrometer can be representative of movement, e.g., displacement or vibration, of the surface being imaged. | 02-19-2009 |
20090251706 | VIBROMETER AND METHOD FOR OPTICALLY MEASURING AN OBJECT - A vibrometer and a method for optically measuring oscillations at an object, including a radiation source for creating a source beam, a beam splitter to split the source beam into a measuring beam and a reference beam, an optic interference device for interfering the reference beam with a measuring beam, at least partially reflected by the object, and a detector, with the interference device and the detector being embodied cooperating such that a measuring beam, at least partially deflected by the object, and the reference beam interfere on the detector. The vibrometer is embodied as a heterodyne vibrometer, having an optic frequency shift unit, which is arranged in the optical path of the vibrometer, to form a carrier frequency by creating a frequency difference between the measuring beam and the reference beam. The beam splitter and the frequency shift unit are embodied as an acousto-optic modulator in an optic construction element to deflect the source beam, with the acousto-optic modulator being embodied such that the source beam entering the acousto-optic modulator can be split into at least two diffraction beams: a first diffraction beam of diffraction order of 1 and a second diffraction beam of diffraction order of −1, and the acousto-optic modulator is arranged in the optical path of the vibrometer such that one of the two diffraction beams represents the measurement beam and the other diffraction beam represents the reference beam. | 10-08-2009 |
20100014096 | OPTICAL SENSING SYSTEM AND OPTICAL DEVICES THEREFOR - A sensing system comprises a light source having three or more distinct wavelengths for illuminating a plurality of distinct areas in a field of view, a sensor for measuring the reflectance of the distinct areas at each of the distinct wavelengths, and an identifier for identifying at least one object in the field of view from the measured reflectance at each of the wavelengths. | 01-21-2010 |
20100128279 | SCANNING MICROSCOPE USING HETERODYNE INTERFEROMETER - The present invention relates to a scanning microscope using a heterodyne interferometer, which can be used for mapping or imaging complex optical parameters such as physical structures and material properties of a sample under test. The heterodyne interferometer is designed to provide in- and quadrature-phase interference signal which can be used for extracting the phase and amplitude change induced on the probe beam. The phase and the amplitude of the probe beam, which is reflected from or transmitted through the sample, are modified by the physical structures and material properties of the sample. Therefore, by scanning the probe beam, local variations of the phase and amplitude can be mapped, and, thereby, three-dimensional microscopic physical structures and material properties can be imaged by processing the phase and amplitude values. | 05-27-2010 |
20100141956 | DUAL BEAM HETERODYNE FOURIER DOMAIN OPTICAL COHERENCE TOMOGRAPHY - The present invention relates to an apparatus and a method combining achromatic complex FDOCT signal reconstruction with a common path and dual beam configuration. The complex signal reconstruction allows resolving the complex ambiguity of the Fourier transform and to enhance the achievable depth range by a factor of two. The dual beam configuration shares the property of high phase stability with common path FDOCT. This is of importance for a proper complex signal reconstruction and is in particular useful in combination with handheld probes such as in endoscopy and catheter applications. The advantages of the present invention are in particular the flexibility to choose arbitrarily positioned interfaces in the sample arm as reference together with the possibility to compensate for dispersion. | 06-10-2010 |
20100253950 | Carrier-Envelope Phase Shift Using Linear Media - The carrier-envelope phase in a train of optical pulses is varied utilizing the dispersive properties of lossless plates while the total dispersion in transmission is maintained practically constant. The plates include sloped surfaces and are mounted for displacement such that the ratio of the thicknesses of the two plates through which the optical pulses will pass can be varied by displacing the plates so as to shift the carrier-envelope phase in the optical pulses. In one embodiment, the plates include a barium fluoride wedge and a fumed silica wedge, wherein the wedges are bond together to form a composite structure with thicker and thinner portions of the wedges inversely matched. | 10-07-2010 |
20110085173 | Phase From Defocused Color Images - Phase differences associated with a defocused wavefront can be determined from a single color image. The color image, which is a measurement of intensity as a function of wavelength, is used to calculate the change in intensity with respect to wavelength over the image plane. The change in intensity can then be used to estimate a phase difference associated with the defocused wavefront using two-dimensional fast Fourier transform solvers. The phase difference can be used to infer information about objects in the path of the defocused wavefront. For example, it can be used to determine an object's shape, surface profile, or refractive index profile. It can also be used to calculate path length differences for actuating adaptive optical systems. Compared to other techniques, deriving phase from defocused color images is faster, simpler, and can be implemented using standard color filters. | 04-14-2011 |
20110096334 | HETERODYNE INTERFEROMETER - A heterodyne interferometer includes a light source, an optical system, and a signal generator including at least two light-receiving elements that respectively output a first signal and a second signal. The signal generator generates a third signal and a fourth signal of which phases are respectively shifted by 90° from phases of the first signal and the second signal, generates a first periodic signal by adding a signal that is obtained by multiplying the first signal and the second signal to a signal that is obtained by multiplying the third signal and the fourth signal, and generates a second periodic signal by subtracting a signal that is obtained by multiplying the first signal and the fourth signal from a signal that is obtained by multiplying the second signal and the third signal. | 04-28-2011 |
20110096335 | HANDHELD INTERFEROMETER BASED WAVELENGTH METER - A handheld wavelength meter that includes a housing that encloses a non-stable reference signal source, an interferometer with rotating retroreflectors, optical-electrical converters, a frequency multiplier, and a controller. | 04-28-2011 |
20110235049 | Wavefront Sensing Method and Apparatus - Wavefront sensing apparatus comprises a beam splitter ( | 09-29-2011 |
20120057170 | DEMODULATION METHOD - A demodulation method for a pseudo-heterodyne signal, wherein the pseudo-heterodyne signal has a phase-modulated carrier signal and the pseudo-heterodyne signal is digitally sampled. A demodulation method at least partially avoids the disadvantages known from the prior art is implemented according to the invention in that the digitally sampled pseudo-heterodyne signal is subjected to a discrete Fourier transformation and at least one output Fourier coefficient featuring an amplitude and a phase is determined, an atan | 03-08-2012 |
20120320381 | MEASUREMENT APPARATUS AND MEASUREMENT METHOD - A measurement apparatus obtains a reference signal from light modulated by a first frequency, obtains a measurement signal from light modulated by the first frequency and a second frequency, and measures a position of a target object by calculating a phase difference between the reference signal and the measurement signal. The apparatus includes: a demodulation unit which demodulates the measurement signal by the first frequency; a decimation filter which removes harmonic components from the signal generated by the demodulation unit; a detection unit which detects periodic error components included in the signal output from the decimation filter; a removing unit which removes the periodic error components from the signal output from the decimation filter; and a calculation unit which calculates the position of the target object based on the signal output from the removing unit. | 12-20-2012 |
20130063728 | MEASURING APPARATUS - A measuring apparatus includes an optical frequency comb source configured to emit an optical frequency comb in which a plurality of frequency components are arranged at equal frequency intervals, a beam splitter configured to split a beam emitted from the optical frequency comb source into a test beam to be irradiated onto a test surface and a reference beam to be irradiated onto a reference surface, an optical path difference changing element configured to change an optical path difference between the reference beam and the test beam, an image sensor configured to capture an interference pattern formed by interference between the test beam and the reference beam, and an analyzer configured to calculate a position of the test surface based upon a signal of the interference pattern captured while the optical path length difference is being changed by the optical path difference changing element. | 03-14-2013 |
20130107276 | DEVICE AND METHOD FOR INTERFEROMETRIC MEASURING OF AN OBJECT | 05-02-2013 |
20130258348 | METHOD AND APPARATUS FOR MEASURING THE REFRACTIVE INDEX OF AIR BASED ON THE LASER SYNTHETIC WAVELENGTH INTERFEROMETRY - The present invention discloses a method and an apparatus for measuring the refractive index of air based on the laser synthetic wavelength interferometry, wherein a laser synthetic wavelength interferometer comprises a dual-frequency laser, a beamsplitter, a first polarizing beamsplitter, a second polarizing beamsplitter, a first corner-cube retroreflector and a second corner-cube retroreflector; a quartz vacuum cavity is disposed in the measuring optical path in parallel to the light propagation direction; when the measurement is performed, air is introduced into the quartz vacuum cavity until it is consistent with outside environment; the variation of the refractive index of air inside the cavity will cause change of the interference signal of the wavelength λ | 10-03-2013 |
20140240715 | Natural light interferometer - Disclosed is a Natural Light Interferometer. The interferometer measures the amplitude and phase distribution of a coherent or incoherent electromagnetic signal, including natural light. In principle, the amplitude and phase distribution of any signal of any wavelength, incoherent or coherent, may be measured using this technique. The corresponding image may be reconstructed as well. The interferometer exploits Fourier transform heterodyne techniques but extends this technology to incoherent signals. The interferometer generates the analyzing signal by exploiting nanotechnology-based signal generation stimulated by the original signal. The Natural Light Interferometer applications include surveillance and reconnaissance; metrology; space-based free-flying, tethered or rigid interferometer arrays; and ground-based sparse interferometer arrays. There is also disclosed a homodyne embodiment of the Natural Light Interferometer that exploits quadrature phase techniques. | 08-28-2014 |
20140253927 | ACOUSTIC SIGNAL RECEIVING APPARATUS AND PHOTO-ACOUSTIC TOMOGRAPHY - An acoustic signal receiving apparatus including: a Fabry-Perot sensor including a Fabry-Perot interferometer configured to convert an acoustic wave into a light intensity signal; a control unit configured to set a first wavelength and a second wavelength; a detecting unit configured to convert light intensities obtained by irradiation of the Fabry-Perot sensor with light from the first light source and the second light source into electric signals; and a signal processing unit configured to acquire a difference between an electric signal corresponding to the first wavelength and an electric signal corresponding to the second wavelength, wherein the control unit is configured to set the first wavelength and the second wavelength so that differential values of reflectivity spectrum of the Fabry-Perot sensor are different at the first wavelength and the second wavelength. | 09-11-2014 |
20140307263 | MEASURING APPARATUS AND ARTICLE MANUFACTURING METHOD - Provided is a measuring apparatus that includes a heterodyne interferometer; a first detector configured to detect interference light between reference light and light to be detected, and output a measured signal; a second detector configured to detect interference light between the first and the second light, and output a reference signal; an oscillator configured to generate a standard signal having a frequency corresponding to a frequency shift amount; a first synchronization detector configured to perform synchronous detection of the measured signal and the standard signal; a second synchronization detector configured to perform synchronous detection of the reference signal and the standard signal; a first processing unit that determines a phase difference between the measured signal and the reference signal based on the outputs of the first synchronization detector and the second synchronization detector; and a second processing unit that determines the position of the object based on the phase difference. | 10-16-2014 |
356485000 | For dimensional measurement (e.g., thickness gap, alignment, profile) | 49 |
20110211197 | HETERODYNE DETECTION DEVICE FOR IMAGING AN OBJECT BY RE-INJECTION - The disclosure relates to a detection device for imaging an object, that comprises: a laser cavity for transmitting an original light signal at an original wavelength towards the object in order to generate an evanescent wave at the surface of the object; a conversion means adapted for converting the evanescent wave into a progressive signal; a re-injection means adapted for injecting the progressive signal into the laser cavity in order to generate interference inside the laser cavity between the progressive signal and the original light signal; a detection means adapted for detecting the interference in order to determine the characteristics of the object; characterised in that the device includes a wavelength modification means adapted so that the wavelength of the progressive signal injected into the laser cavity is different from the original wavelength. | 09-01-2011 |
20120257213 | APPARATUS AND METHOD FOR DETERMINING A DEPTH OF A REGION HAVING A HIGH ASPECT RATIO THAT PROTRUDES INTO A SURFACE OF A SEMICONDUCTOR WAFER - An apparatus and method for determining a depth of a region having a high aspect ratio that protrudes into a surface of a semiconductor wafer are provided. The apparatus comprises a multi-wavelength light source, a semiconductor wafer holder for holding a semiconductor wafer, a head for directing the light source onto the semiconductor wafer, a spectrometer for collecting light comprising multiple wavelengths reflected from the semiconductor wafer and analysis means for determining a depth of the region from an interference pattern of light reflected from the semiconductor wafer by performing Fourier domain optical coherence tomography. | 10-11-2012 |
20140368830 | Optical Measurement Device for Detecting Distance Differences and Optical Measurement Method - The invention relates to an optical measuring device for acquiring in situ a difference in distance between a support and an edge region of an object to be measured. The optical measuring device has a measuring head with dual beam guide which directs a first measuring beam towards the support and a second measuring beam towards the edge region of the object to be measured. Means are provided for acquiring and forming reflection spectra of the first measuring beam which is directed towards the support and the second measuring beam which is directed towards the edge region of the object to be measured. The measuring device has a multi-channel measuring apparatus with one spectrometer line. An evaluation unit for the reflection spectra for acquiring the stage height between the support and the edge region of the object works together with a spectrometer and a display unit. | 12-18-2014 |
356486000 | Displacement or distance | 38 |
20080304077 | CYCLIC ERROR COMPENSATION IN INTERFEROMETRY SYSTEMS - A first portion of a beam including a first frequency component is directed along a first path. A second portion of the beam is frequency shifted to generate a shifted beam that includes a second frequency component different from the first frequency component and one or more spurious frequency components different from the first frequency component. At least a portion of the shifted beam is directed along a second path different from the first path. An interference signal S(t) from interference between the beam portions directed along the different paths is measured. The signal S(t) is indicative of changes in an optical path difference n{tilde over (L)}(t) between the paths, where n is an average refractive index along the paths, {tilde over (L)}(t) is a total physical path difference between the paths, and t is time. An error signal is provided to reduce errors in an estimate of {tilde over (L)}(t) that are caused by at least one of the spurious frequency components of the shifted beam, the error signal being derived at least in part based on the signal S(t). | 12-11-2008 |
20090153872 | CHIRPED COHERENT LASER RADAR SYSTEM AND METHOD - A laser radar system using collocated laser beams to unambiguously detects a range of a target and a range rate at which the target is moving relative to the laser radar system. Another aspect of various embodiments of the invention may relate to a laser radar system that uses multiple laser radar sections to obtain multiple simultaneous measurements (or substantially so), whereby both range and range rate can be determined without various temporal effects introduced by systems employing single laser sections taking sequential measurements. In addition, other aspects of various embodiments of the invention may enable faster determination of the range and rate of the target, a more accurate determination of the range and rate of the target, and/or may provide other advantages. | 06-18-2009 |
20090213385 | Multi-Phase Interferometer - An optical perturbation sensing system includes a probing beam incident on a medium with perturbations and a sensing beam redirected from the medium and incident on a surface area of a photodetector. A reference beam directed onto the photodetector surface forms, with the sensing beam, an interference pattern on the photodetector surface and a phase patterner with at least two phase regions across its section, generates different phases in different regions of the interference pattern. An array of photodetector elements detects each phase region of the interference pattern and a constructive combiner subtract pairs of the detected signals, squares the subtracted signal squares, and sums the squared signals to form a stronger detected signal with reduced intensity noise, reduced background noise, and reduced sensitivity to phase drifts. | 08-27-2009 |
20100046003 | METHOD AND DEVICE FOR GENERATING A SYNTHETIC WAVELENGTH - In a method for generating a synthetic wavelength, particularly for an interferometric distance measuring setup, with a primary laser source defining a primary frequency U | 02-25-2010 |
20100177318 | Laser interferometer - A laser interferometer includes: a laser source for emitting a laser beam while stabilizing a center wavelength of the laser beam by modulating the laser beam using a modulation signal of a predetermined frequency; and a reference mirror and a measurement mirror for reflecting the laser beam. The laser interferometer further includes: a sampling unit for acquiring a sampling value by sampling interference light reflected by the reference mirror and the measurement mirror with a sampling frequency that is a multiple by an integer of two or more of a frequency of the modulation signal; and an average calculator for calculating an average value by averaging a time-series sampling value acquired by the sampling unit in accordance with the sampling frequency. The laser interferometer calculates a displacement of the measurement mirror based on the average value calculated by the average calculator. | 07-15-2010 |
20110096336 | APPARATUS AND METHOD FOR MEASURING DISPLACEMENT - The apparatus and method for measuring displacement according to the present invention includes a first beam and a second beam. A first reflection structure reflects a first beam to the surface of an object under test; and a second reflection structure reflects a second beam to the surface of the object under test. The reflected first beam and the reflected second beam have an optical path difference. The object under test scatters a scattering beam of gathering the first and second beams. The scattering beam has an interference signal. A photodetector receives the interference signal of the scattering beam. Then an operational unit receives and computes the interference signal for producing a displacement value. By using the first and second reflection structures, the first and second beams split from an incident beam produce an optical path difference. Thereby, the structure of the apparatus for measuring displacement can be simplified. Besides, the displacement or the amplitude of vibration of the object under test can be measured effectively. | 04-28-2011 |
20110249270 | HETERODYNE INTERFEROMETRY DISPLACEMENT MEASUREMENT APPARATUS - A heterodyne interferometry displacement measurement apparatus includes a first optical system including a light source (LASER) and a diffraction grating (GT | 10-13-2011 |
20120038930 | FIXED WAVELENGTH ABSOLUTE DISTANCE INTERFEROMETER - A fixed wavelength absolute distance interferometer including a first interferometer comprising a first light source transmitting a first light beam having a wavelength W toward a measurement target, a wavefront radius detector configured to provide a first measurement responsive to the wavefront radius at the wavefront radius detector, and a first path length calculating portion calculating a coarse resolution absolute path length measurement R; and a second interferometer comprising a beam transmitting device transmitting a second-interferometer light beam having a wavelength Λ, a beam splitting/combining device separating the second-interferometer light beam into reference and measurement beams and combining the returning reference and measurement beams into a combined beam, a second-interferometer detector configured to receive the combined beam and provide signals of a phase φ of the combined beam, and a second path length calculating portion configured to determine a medium resolution absolute path length measurement Z | 02-16-2012 |
20120147382 | MEASUREMENT APPARATUS - A measurement apparatus obtains a reference signal from reference light modulated at a first frequency and a measurement signal from measurement light reflected by a target object modulated at a second frequency along with movement of the target object in addition to the modulation at the first frequency, and processes the reference signal and the measurement signal to measure a position of the target object. Synchronized detection units multiply the measurement signal by a signal synchronized with the reference signal and output signals having the second frequency and harmonic components. Decimation filters filter, at a decimation frequency, the signals output from the synchronized detection units to attenuate the harmonic components. | 06-14-2012 |
20120242998 | METHOD FOR SPECKLE MITIGATION IN AN INTERFEROMETRIC DISTANCE METER AND CORRESPONDING DISTANCE METER - A method for speckle mitigation in an interferometric distance meter comprises the steps of transmitting optical radiation with at least one wavelength λ to a target to be surveyed, receiving a portion of the optical radiation scattered back by the target in an optical axis (OA), wherein the optical radiation forms a speckle field, converting the received optical radiation into at least one received signal, determining a true distance to the target from the received signal by absolute or incremental interferometric distance measurements. In the method the true pointing direction relative to the optical axis (OA) is determined, wherein the distance error due to speckle effects is corrected. | 09-27-2012 |
20130063729 | OBSERVATION DEVICE - Provided is an observation device which can obtain a phase image of a moving object rapidly with high sensitivity even when using a photodetector having a slow read-out speed per pixel. The observation device | 03-14-2013 |
20130114087 | LOW COHERENCE INTERFEROMETRY USING ENCODER SYSTEMS - A method for determining information about changes in a position of an encoder scale includes separating, in a first interferometry cavity, a low coherence beam into a first beam propagating along a first path of the first interferometry cavity and a second beam propagating along a second path of the first interferometry cavity, combining the first beam and the second beam to form a first output beam, separating, in a second interferometry cavity, the first output beam into a measurement beam propagating along a measurement path of the second interferometry cavity and a reference beam propagating along a reference path of the second interferometry cavity, combining the measurement beam and the reference beam to form a second output beam, detecting an interference signal based on the second output beam, and determining the information about changes in the position of the encoder scale based on phase information from the interference signal. | 05-09-2013 |
20130201486 | Level Sensor Arrangement for Lithographic Apparatus, Lithographic Apparatus and Device Manufacturing Method - Disclosed is a method of measuring a position of at least one substantially reflective layer surface on a substrate in a lithographic apparatus, and associated level sensor and lithographic apparatuses. The method comprises performing at least two interferometrical measurements using a broadband light source. Between each measurement, the component wavelengths and/or intensity levels over the component wavelengths of the broadband source beam is varied such that, where it is only the intensity levels that are varied, the intensity variation is different for at least some of the beam's component wavelengths. Alternatively, a single measurement and subsequent processing of the measurement to obtain measurement data whereby the component wavelengths and/or intensity levels over the component wavelengths are different can be applied as well to obtain the position. | 08-08-2013 |
20130301056 | NONCONTACT INTERFEROMETRIC SENSOR AND METHOD OF USE - An interferometric sensor having an interference objective, an illumination system, and a detection system configured to simultaneous non-contact determination of profile and roughness of a tested surface. The illumination system comprises a radiation source configured to emit three wavelengths of quasi-monochromatic light. The sensor further includes a detection system having a color array detector in optical communication with the interference objective and configured to detect the light reflected by the measurand. The sensitivity of measurement can be adjusted by re-orienting of a portion of the sensor with respect to the measurand. | 11-14-2013 |
20140049782 | INTERFEROMETRIC ENCODER SYSTEMS - A method for determining information about changes along a degree of freedom of an encoder scale includes directing a first beam and a second beam along different paths and combining the first and second beams to form an output beam, where the first and second beams are derived from a common source, the first and second beams have different frequencies, where the first beam contacts the encoder scale at a non-Littrow angle and the first beam diffracts from the encoder scale at least once; detecting an interference signal based on the output beam, the interference signal including a heterodyne phase related to an optical path difference between the first beam and the second beam; and determining information about a degree of freedom of the encoder scale based on the heterodyne phase. | 02-20-2014 |
20140320864 | INTERFEROMETRIC MILLIMETER WAVE AND THZ WAVE DOPPLER RADAR - A mixerless high frequency interferometric Doppler radar system and methods has been invented, numerically validated and experimentally tested. A continuous wave source, phase modulator (e.g., a continuously oscillating reference mirror) and intensity detector are utilized. The intensity detector measures the intensity of the combined reflected Doppler signal and the modulated reference beam. Rigorous mathematics formulas have been developed to extract bot amplitude and phase from the measured intensity signal. Software in Matlab has been developed and used to extract such amplitude and phase information from the experimental data. Both amplitude and phase are calculated and the Doppler frequency signature of the object is determined. | 10-30-2014 |
356487000 | Polarization | 22 |
20080309946 | Differential-phase interferometric system - A differential-phase interferometric system includes a polarized heterodyne interferometer for generating reference and signal beam that travel along reference and signal channels, respectively. The signal beam is directed to a specimen and contains measured information of the specimen. The interferometer further generates a first electrical signal output corresponding to first linear polarized waves of the reference and signal beams, and a second electrical signal output corresponding to second linear polarized waves of the reference and signal beams. A differential amplifier receives the first and second electrical signal outputs, and generates a differential signal output therefrom. A data acquisition unit is used to measure amplitudes of the first and second electrical signal outputs and the differential signal output. A computing unit computes the amplitudes measured by the data acquisition unit to determine a phase difference between the electrical signal outputs, which corresponds to the measured information of the specimen. | 12-18-2008 |
20090135430 | Systems and Methods for Reducing Nonlinearity in an Interferometer - A system for measuring electromagnetic interference, the system comprising: a plane mirror interferometer receiving a first electromagnetic beam and a second electromagnetic beam having a same linear polarization, each of the first and second electromagnetic beams transmitted on separate paths such that the beams are non-overlapping until immediately before detection of the beams, wherein the interferometer includes: a reference surface and a measurement surface, the reference surface reflecting the first beam, and the measurement surface reflecting the second beam; and a polarization beam splitter, wherein the first and second beams enter the polarization beam splitter at a same facet of the polarization beam splitter. | 05-28-2009 |
20090310141 | TWO-WAVELENGTH LASER INTERFEROMETER AND METHOD OF ADJUSTING OPTICAL AXIS IN THE SAME - A two-wavelength laser interferometer includes: a two-wavelength laser light source that emits two laser beams having different wavelengths; a two-wavelength polarizing beam splitter that includes a beam splitter and a beam superposer, the beam splitter splitting each of the two laser beams having the different wavelengths into a reference beam and a measurement beam, the beam superposer superposing the reference beam and the measurement beam reflected by a reference surface and a target measurement surface together; and a calculator that obtains a displacement amount of the target measurement surface per wavelength from the beams superposed together and obtains a displacement amount of the target measurement surface applied with atmospheric refractive index correction through a calculation in which the displacement amount obtained per wavelength is used. In the two-wavelength laser interferometer, an optical-axis superposer is provided between the two-wavelength laser light source and the beam splitter. The optical-axis superposer initially separates the two laser beams having the different wavelengths emitted from the two-wavelength laser light source and subsequently superposes optical axes of the two laser beams together. | 12-17-2009 |
20100027026 | Displacement measuring instrument and displacement measuring method - A laser interferometric measuring instrument includes: a light source that emits a laser beam of 1064 nm and another laser beam of 532 nm; a polarizing beam splitter; a dichroic mirror that splits a long-wavelength laser beam provided in a measurement optical path; a long-wavelength corner cube that reflects the split laser beam; a measurement corner cube that is displaceable along the measurement optical path; a reference corner cube that is displaceable along a reference optical path; a optical path changing unit that changes an optical path length of the long-wavelength laser beam; a phase detector that outputs interference signals; a sum signal computer that calculates a sum signal; a displacement controller that displaces the reference corner cube so as not to change a phase of the sum signal; a reference displacement detector that detects a displacement of the reference corner cube; and a measurement displacement computer that calculates a displacement of the measurement corner cube. | 02-04-2010 |
20100039652 | METHOD AND APPARATUS FOR MEASURING DISPLACEMENT OF A SAMPLE - In a displacement measurement apparatus using light interference, a probe light path is spatially separated from a reference light path. Therefore, when a temperature or refractive index distribution by a fluctuation of air or the like, or a mechanical vibration is generated, an optical path difference fluctuates between both of the optical paths, and a measurement error is generated. In the solution, an optical axis of probe light is brought close to that of reference light by a distance which is not influenced by any disturbance, a sample is irradiated with the probe light, a reference surface is irradiated with the reference light, reflected light beams are allowed to interfere with each other, and a displacement of the sample is obtained from the resultant interference light to thereby prevent the measurement error from being generated by the fluctuation of the optical path difference. | 02-18-2010 |
20100067019 | Differential-Phase Polarization-Sensitive Optical Coherence Tomography System - A differential-phase polarization-sensitive optical coherence tomography system includes a polarized heterodyne interferometer for generating a reference beam to be reflected by a movable mirror unit, and a signal beam to be reflected by an imaging plane in a specimen. The interferometer further generates a first electrical signal output corresponding to first linear polarized waves of the reference and signal beams, and a second electrical signal output corresponding to second linear polarized waves of the reference and signal beams. A differential amplifier receives the first and second electrical signal outputs, and generates a differential signal output therefrom. A data acquisition unit is used to measure amplitudes of the first and second electrical signal outputs and the differential signal output. A computing unit computes the amplitudes measured by the data acquisition unit to determine a reflectivity, a phase retardation, and a fast axis angle of the imaging plane in the specimen. | 03-18-2010 |
20100141957 | LASER INTERFEROMETER SYSTEM FOR MEASURING ROLL ANGLE - A laser interferometer system for measuring roll angle around the direction of linear displacement comprises a light source of a frequency stabilized input beam ( | 06-10-2010 |
20100225924 | OPTICAL INTERFERENCE MEASURING APPARATUS - An optical interference measuring apparatus comprises a first multiple-wavelength light source | 09-09-2010 |
20100259759 | POLARIMETER EMPLOYING A FIZEAU INTERFEROMETER - A polarimeter based on a modified Fizeau interferometer and a method for measuring the optical rotation of a polarized light beam by an optically active substance using the polarimeter, are provided. | 10-14-2010 |
20110157598 | Multi-beam interferometer displacement measuring system utilized in a large measuring range - A multi-beam interferometer displacement measuring system has a light source module, a resonator module and a detecting device. The light source module has an emitter and a polaroid sheet. The emitter emits a non-polarizing beam. The polaroid sheet receives and transforms the non-polarizing beam into a polarizing beam. The resonator module receives the polarizing beam and has a coated glass panel, a corner cube prism and a wave-delay plate. The coated glass panel receives and reflects the polarizing beam. The corner cube prism receives and reflects the polarizing beam to the coated glass panel to form a resonant cavity. The wave-delay plate is mounted between the coated glass panel and the corner cube prism to receive the polarizing beam. The detecting device faces the coated glass panel to receive the interferential stripes formed in the resonator module and has a polarizing beam splitter, two power detectors and a signal processor. | 06-30-2011 |
20120170048 | INTERFEROMETRIC ENCODER SYSTEMS - A method for determining information about changes along a degree of freedom of an encoder scale includes directing a first beam and a second beam along different paths and combining the first and second beams to form an output beam, where the first and second beams are derived from a common source, the first and second beams have different frequencies, where the first beam contacts the encoder scale at a non-Littrow angle and the first beam diffracts from the encoder scale at least once; detecting an interference signal based on the output beam, the interference signal including a heterodyne phase related to an optical path difference between the first beam and the second beam; and determining information about a degree of freedom of the encoder scale based on the heterodyne phase. | 07-05-2012 |
20120250026 | INTERFEROMETER MODULE - The invention relates to a differential interferometer module adapted for measuring a direction of displacement between a reference mirror and a measurement mirror. In an embodiment the differential interferometer module is adapted for emitting three reference beams towards a first mirror and three measurement beams towards a second mirror for determining a displacement between said first and second mirror. In a preferred embodiment the same module is adapted for measuring a relative rotation around two perpendicular axes as well. The present invention further relates to a lithography system comprising such a interferometer module and a method for measuring such a displacement and rotations. | 10-04-2012 |
20140160489 | FOUR-AXIS FOUR-SUBDIVIDING INTERFEROMETER - Four-axis four-subdividing interferometer comprising a four-axis light splitting module and an interference module which are sequentially arranged along the incident direction of polarization orthogonal double-frequency laser. The four-axis light splitting system comprises three 50% plane beam splitters and three 45-degree plane reflecting mirrors. The invention comprises a four-axis four-subdividing plane mirror interferometer and a four-axis four-subdividing differential interferometer. In the differential interferometer, an adjustable 45-degree reflecting minor is used to guide the reference light to a reference reflecting minor which is arranged in the same direction as a measurement minor and fixed on the moving object. | 06-12-2014 |
20140218746 | OPTICAL POSITION-MEASURING DEVICE - The present invention relates to an optical position-measuring device for generating a plurality of phase-shifted scanning signals regarding the relative position of a fiber optic scanning head and a reflection measuring standard movable relative thereto in at least one measuring direction. In the fiber optic scanning head, a scanning reticle is disposed before the measuring standard end of an optical fiber. The scanning signals are coded in a wavelength-dependent manner. To this end, a beam incident on the scanning reticle is split into at least two sub-beams which strike the reflection measuring standard and are subsequently recombined to interfere with each other so as to generate the phase-shifted scanning signals. The sub-beams travel different optical path lengths between splitting and recombination. | 08-07-2014 |
20150043004 | HIGH SPEED HIGH RESOLUTION HETERODYNE INTERFEROMETRIC METHOD AND SYSTEM - A high speed high resolution heterodyne interferometric method and system are provided. The invention uses two spatially separated beams with slightly different frequencies and has two measurement signals with opposite Doppler shift. The switching circuit selects one of the two measurement signals for displacement measurement according to the direction and speed of the target movement. In this invention, the measurement is insensitive to the thermal variation; the periodic nonlinearity is essentially eliminated by using two spatially separated beams; the measurable target speed of the interferometer is no longer limited by the beat frequency of the laser source. | 02-12-2015 |
20150043005 | INTERFEROMETRIC HETERODYNE OPTICAL ENCODER SYSTEM - An encoder interferometry system includes an interferometer positioned to receive first and second beams having different frequencies, in which the interferometer has at least one polarizing beam splitting element for directing the first beam along a measurement path to define a measurement beam and the second beam along a reference path to define a reference beam. The encoder interferometry system further includes a encoder scale positioned to diffract the measurement beam at least once, a detector positioned to receive the measurement and reference beams after the measurement beam diffracts from the encoder scale, and an output component positioned to receive the measurement and reference beams before they reach the detector and deflect spurious portions of the first and second beam away from the detector. | 02-12-2015 |
20150338205 | HETERODYNE GRATING INTERFEROMETER DISPLACEMENT MEASUREMENT SYSTEM - A displacement measurement system of heterodyne grating interferometer, comprises a reading head, a measurement grating and an electronic signal processing component. Laser light emitted from the laser tube is collimated, passes through the first polarization spectroscope, and then emits two light beams with a vertical polarization direction and a vertical propagation direction; the two light beams pass through two acousto-optic modulators and respectively generate two first-order diffraction light beams with different frequencies, which are later divided into reference light and measurement light; two parallel reference light beams form a beat frequency electric signal with positive and negative first-order diffraction measurement light respectively after passing through a measurement signal photo-electric conversion unit; the beat frequency signals are transmitted to the electronic signal processing component for signal processing, thus the output of linear displacement in two directions is realized. | 11-26-2015 |
356488000 | Having wavefront division (e.g., by diffraction) | 5 |
20090147265 | DETECTION SYSTEM FOR DETECTING TRANSLATIONS OF A BODY - The invention relates to a system ( | 06-11-2009 |
20110255096 | INTERFEROMETRIC ENCODER SYSTEMS - A method for determining information about changes along a degree of freedom of an encoder scale includes directing a first beam and a second beam along different paths and combining the first and second beams to form an output beam, where the first and second beams are derived from a common source, the first and second beams have different frequencies, where the first beam contacts the encoder scale at a non-Littrow angle and the first beam diffracts from the encoder scale at least once; detecting an interference signal based on the output beam, the interference signal including a heterodyne phase related to an optical path difference between the first beam and the second beam; and determining information about a degree of freedom of the encoder scale based on the heterodyne phase. | 10-20-2011 |
20160102999 | INTERFEROMETRIC ENCODER SYSTEMS - An encoder interferometry system includes an encoder scale arranged to receive and diffract a measurement beam. The system further includes one or more optical elements configured and arranged to receive a first diffracted measurement beam and a second diffracted measurement beam from the encoder scale and to redirect the first diffracted measurement beam and the second diffracted measurement beam toward the encoder scale such that the first diffracted measurement beam and the second diffracted measurement beam propagate along non-parallel beam paths having an angular separation α following a second diffraction at the encoder scale. The system further includes a first detector arranged to receive the first diffracted measurement beam and a second detector arranged to receive the second diffracted measurement beam. | 04-14-2016 |
20160138903 | TWO-DOF HETERODYNE GRATING INTERFEROMETER DISPLACEMENT MEASUREMENT SYSTEM - A two-DOF heterodyne grating interferometer displacement measurement system, comprising a dual-frequency laser, a grating interferometer, a measurement grating, receivers and an electronic signal processing component, wherein the grating interferometer comprises a polarizing spectroscope, a reference grating and dioptric elements. The measurement system achieves the displacement measurement on the basis of the grating diffraction, the optical Doppler effect and the optical beat frequency principle. When the grating interferometer and the measurement grating conduct two-DOF linear relative motion, the system can output two linear displacements. The measurement system can achieve sub-nanometer or even higher resolution and accuracy, and can simultaneously measure two linear displacements. The measurement system has the advantages of insensitivity to the environment, high measurement accuracy, a small volume and light weight, and can improve the comprehensive performance of a workpiece stage as a position measurement system for an ultra-precise workpiece stage of a photoetching machine. | 05-19-2016 |
20160153764 | THREE-DOF HETERODYNE GRATING INTERFEROMETER DISPLACEMENT MEASUREMENT SYSTEM | 06-02-2016 |
356489000 | Contour or profile | 7 |
20100020329 | SHAPE MEASURING METHOD - A method for detecting shapes based on interferometric observation of an object surface subjected to narrow-band lighting. Movement of the interferometer ( | 01-28-2010 |
20130088722 | MEASUREMENT APPARATUS - A measurement apparatus includes: a first light source which generates first light containing a scan section in which a wavelength is scanned between a first wavelength and a second wavelength; a second light source which generates second light having a third wavelength; a first detector and a second detector which respectively detect first and second interference signals generated by irradiating a reference surface and a test surface with the first and second light; a calculation unit which calculates, based on data of a phase of the second interference signal, one of the position and shape of the test surface by using the third wavelength as a measurement wavelength that determines a measurement range. | 04-11-2013 |
20130100458 | MULTI-WAVELENGTH INTERFEROMETER, MEASUREMENT APPARATUS, AND MEASUREMENT METHOD - A multi-wavelength interferometer includes a beam splitter configured to split plural light fluxes into a reference beam and a measurement beam, a frequency shifter configured to shift a frequency of at least one of the reference beam and the measurement beam to make the frequencies of the reference beam and the measurement beam different from each other, an optical system configured to cause the measurement beam to be incident on a measurement surface and to cause the measurement beam reflected from the measurement surface to interfere with the reference beam to obtain interference light, a dividing unit configured to divide the interference light into a plurality of light beams, and a detection unit configured to detect the plurality of light beams divided by the dividing unit. | 04-25-2013 |
20130155414 | MEASURING APPARATUS INCLUDING MULTI-WAVELENGTH INTERFEROMETER - A measuring apparatus for measuring a position or a shape of a surface to be inspected includes a multi-wavelength interferometer and a control unit. The multi-wavelength interferometer includes an optical system that causes light to be inspected, which enters the surface to be inspected and is reflected by the surface to be inspected, and reference light to interfere with each other, a spectroscopic unit that divides interference light between the light to be inspected and the reference light into each wavelength, and a detector that detects the interference light and is provided for each divided interference light and an optical member that can adjust a position of a light guide portion that guides light from the spectroscopic unit to the detector. The control unit controls the optical member by using information related to inclination of the surface to be inspected to adjust the position of the light guide portion. | 06-20-2013 |
20130235385 | SURFACE SHAPE MEASUREMENT METHOD AND MEASUREMENT APPARATUS - A method of measuring a surface shape of a target object by irradiating a target object and a reference surface with coherent light while changing a frequency of the coherent light includes: setting a rate of changing the frequency of the coherent light based on at least one of first information of a contour of an image of the target object projected onto a surface perpendicular to an optical axis of a measurement light and known second information of the surface shape; obtaining, by an image sensor, a plurality of images of interference fringes while changing the frequency of the coherent light with which the target object and the reference surface are irradiated at the set rate; and obtaining the surface shape based on the obtained plurality of images. | 09-12-2013 |
20160054117 | MEASUREMENT APPARATUS, MEASUREMENT METHOD, AND METHOD OF MANUFACTURING ARTICLE - The present invention provides a measurement apparatus for measuring a shape of a test surface, comprising an optical system configured to irradiate a measurement point on the test surface and a reference surface with light, and cause test light and reference light reflected to interfere with each other, a detector configured to detect an optical path length difference between the test light and the reference light by using interfering light and a processor configured to determine a position of the measurement point based on a plurality of detection results by the detector, wherein a detection result includes an error which cyclically changes, and the plurality of detection results include n detection results obtained in n states in which optical path lengths of the test light are different from each other by 1/n (n≧2) of a cycle of the error. | 02-25-2016 |
20160091299 | INTERFEROMETRIC NON-CONTACT OPTICAL PROBE AND MEASUREMENT - A non-contact optical probe utilizes an optical reference surface that projects a curved test wavefront toward the test surface and detects it by creating curved interferometric fringes localized in space in front of the reference surface. When a point to be measured on the test surface intersects the location of the fringes, the condition is detected by the probe. Because the fringes are localized at a known position in space with respect to a reference system, the precise coordinate of the surface point can be established. Such localized fringes are preferably produced by a spectrally controllable light source. The curvature of the fringes ensures a sufficiently large angle of acceptance for the probe to capture light reflected from points of high surface slope. The probe is particularly suitable for coordinate measurement machines. | 03-31-2016 |
356490000 | Alignment | 1 |
20100214569 | Semiconductor Apparatus Including Alignment Tool - Provided is a semiconductor apparatus. The semiconductor apparatus includes a reference grating and a plurality of detectors. The reference grating diffracts an optical signal generated by being reflected from the alignment grating of a substrate to diffraction beams with different orders. The plurality of detectors measure intensities of a plurality of diffraction beams selected from the diffraction beams, respectively. | 08-26-2010 |