Having Wavefront Division (by Diffraction) Patents (Class 356/521)
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Patent number: 6940607Abstract: In the case of a method for absolute calibration of an interferometer with the aid of a spherical output wave, comprising an optical element which retroflects the incident spherical wave itself or via a mirror, at least four measuring procedures are undertaken to determine a wave aberration W. The optical element is measured in the at least four measuring positions intrafocally and extrafocally in at least two different rotational angle positions. It is also possible, in addition, to undertake a measurement via a mirror in the cat's eye position (focus 3).Type: GrantFiled: May 21, 2002Date of Patent: September 6, 2005Assignee: Carl Zeiss SMT AGInventors: Rolf Freimann, Maximilian Mayer, Stephan Reichelt
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Patent number: 6934038Abstract: The present invention is directed at a coherence test reticle or lithographic plate, and a method for testing the coherence of a laser beam using the test reticle. The quality or coherence of the laser beam is measured by illuminating the test reticle and the recording and/or analyzing the optical patterns generated by the illumination. The technique was designed for, but not limited to, the characterization of laser-based systems via the detection of optical radiation modulated by transmissive, reflective and diffractive patterns printed on a reticle or lithographic plate designed specifically for this purpose. The novelty and advantages over the prior art are insensitivity to vibration, alignment, and multi-path differences of classical interferometric coherence measurement techniques. Spatial coherence and longitudinal or temporal coherence may be measured independently. Vertical and horizontal coherence may be measured independently. The technique is focus error insensitive.Type: GrantFiled: July 6, 2001Date of Patent: August 23, 2005Assignee: ASML Holding N.V.Inventor: Matthew E. Hansen
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Patent number: 6924899Abstract: A wavefront tilt measurement system for measuring the wavefront tilt of light passing through transmitting or receiving optical systems, the optical systems including a primary aperture and internal optical elements defining an optical system focal plane. A light source emits light at the optical system focal plane towards the internal optical elements such that light from the light source emerges from the primary aperture. A plurality of tilt sensors are disposed adjacent to the primary aperture to receive light emerging from the primary aperture. Each tilt sensor includes a sensor focal plane and a plurality of detector elements. Each tilt sensor generates at the focal plane a plurality of overlapping regions of zero and first order images of light emerging from the primary aperture. The measured intensity of light in the overlapping regions is used to determine the wavefront tilt of light emerging from the primary aperture.Type: GrantFiled: May 31, 2002Date of Patent: August 2, 2005Assignee: Optical Physics CompanyInventors: Richard A. Hutchin, Oberdan W. Otto
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Patent number: 6909512Abstract: A method is provided for reducing the piston of neighboring first and second surfaces illuminated by polychromatic light transmitted from an unresolved-light source such that light transmitted or reflected from the first surface is out of phase with light respectively transmitted or reflected from the second surface, and the out-of-phase light is passed through a grism that generates a fringe pattern in the far-field. According to one exemplary embodiment, the method includes Fourier transforming the fringe pattern to generate a two-dimensional (2D) power spectrum; generating the absolute value of the 2D power spectrum to form an absolute value representation; displaying the 2D the absolute value representation on a computer display; and reducing the piston to affect rotation of the absolute value representation on the computer display and approximately align a central axis of the absolute value representation with an axis that indicates approximate alignment of the first and second surfaces.Type: GrantFiled: May 30, 2003Date of Patent: June 21, 2005Assignee: Lockheed Martin CorporationInventors: Gopal Vasudevan, Eric Hartel Smith, Robert Duncan Reardon
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Patent number: 6876456Abstract: The invention uses the phase shifting diffraction interferometer (PSDI) to provide a true point-by-point measurement of absolute flatness over the surface of optical flats. Beams exiting the fiber optics in a PSDI have perfect spherical wavefronts. The measurement beam is reflected from the optical flat and passed through an auxiliary optic to then be combined with the reference beam on a CCD. The combined beams include phase errors due to both the optic under test and the auxiliary optic. Standard phase extraction algorithms are used to calculate this combined phase error. The optical flat is then removed from the system and the measurement fiber is moved to recombine the two beams. The newly combined beams include only the phase errors due to the auxiliary optic. When the second phase measurement is subtracted from the first phase measurement, the absolute phase error of the optical flat is obtained.Type: GrantFiled: September 27, 2002Date of Patent: April 5, 2005Assignee: The Regents of the University of CaliforniaInventor: Gary E. Sommargren
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Patent number: 6870630Abstract: A sensor platform for use in sample analysis comprises a substrate (30) of refractive index (n1) and a thin, optically transparent layer (32) of refractive index (n2) on the substrate, (n2) is greater than (n1). The platform incorporates one or multiple corrugated structures in the form of periodic grooves (31), (33), which defines one or more sensing areas each for one or more capture elements. The grooves are so profiled, dimensioned and oriented that when coherent light is incident on the platform it is diffracted into individual beams or diffraction order resulting in reduction of the transmitted beam and an abnormal high reflection of the incident light thereby creates an enhanced evanescent field at the surface of the or each sensing area. The amplitude of this field at the resonant condition is greater by an order of approximately 100 than the field of prior art platforms so that the luminescence intensity created from samples on the platform is also increased by a factor of 100.Type: GrantFiled: October 9, 2003Date of Patent: March 22, 2005Assignee: Novartis AGInventors: Wolfgang Ernst Gustav Budach, Dieter Neuschaefer
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Patent number: 6867869Abstract: A sensor platform for use in sample analysis comprises a substrate (30) of refractive index (n1) and a thin, optically transparent layer (32) of refractive index (n2) on the substrate, (n2) is greater than (n1). The platform incorporates one or multiple corrugated structures in the form of periodic grooves (31), (33), which defines one or more sensing areas each for one or more capture elements. The grooves are so profiled, dimensioned and oriented that when coherent light is incident on the platform it is diffracted into individual beams or diffraction order resulting in reduction of the transmitted beam and an abnormal high reflection of the incident light thereby creates an enhanced evanescent field at the surface of the or each sensing area. The amplitude of this field at the resonant condition is greater by an order of approximately 100 than the field of prior art platforms so that the luminescence intensity created from samples on the platform is also increased by a factor of 100.Type: GrantFiled: October 9, 2003Date of Patent: March 15, 2005Assignee: Novartis AGInventors: Wolfgang Ernst Gustav Budach, Dieter Neuschaefer
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Patent number: 6850325Abstract: The present invention relates to an apparatus for the determination of a condition or state of an object based on quasi-elastic interaction between the object and light transmitted to the object, the apparatus comprising a diffractive optical element having a diffracting region comprising a first diffracting structure for diffraction and focussing of a first light beam to the object, and a second diffracting structure that is laterally displaced relative to the first diffracting structure for diffraction and focussing of a second light beam to the object. The first and second diffracting structures focus the first and second light beams in the same focussing plane, the focussing plane being substantially perpendicular to propagation directions of the first and second light beams. The diffracting region further comprises a receiving diffracting structure for diffraction of light from the light beams that has interacted with the object. The diffracted light is diffracted in a diffraction angle.Type: GrantFiled: July 3, 2003Date of Patent: February 1, 2005Assignee: Kamstrup A/SInventor: Carsten Dam-Hansen
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Publication number: 20040263821Abstract: A system for microlithography comprises an illumination source; an illumination optical system including, in order from an objective side, (a) a first diffractive optical element that receives illumination from the illumination source, (b) a zoom lens, (c) a second diffractive optical element, (d) a condenser lens, (e) a relay lens, and (f) a reticle, and a projection optical system for imaging the reticle onto a substrate, wherein the system for microlithography provides a zoomable numerical aperture.Type: ApplicationFiled: July 22, 2004Publication date: December 30, 2004Applicant: ASML Holding N.V.Inventors: Mark Oskotsky, Lev Ryzhikov, Scott Coston, James Tsacoyeanes, Walter Augustyn
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Publication number: 20040227956Abstract: A plurality of gratings (G1, G2) are arranged to provide an aperture for incident light, which is diffracted by the gratings, which is larger than a single monolithic grating, and is operative to add coherently the energy from each grating so that it is operative in a coherently additive mode like a monolithic grating. Interacting movements in displacement and rotation are corrected by piston shifts of the gratings in the array in the direction perpendicular to the plane of the gratings. The shifts are implemented by displacing one grating with respect to another grating of the pair of gratings (G1, G2) in the array, or in the case of multiple gratings, other gratings in the array with respect to an aligned pair of array gratings.Type: ApplicationFiled: April 30, 2004Publication date: November 18, 2004Inventors: Terrance J. Kessler, Joachim Bunkenburg, Hu Huang
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Patent number: 6819435Abstract: 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.Type: GrantFiled: April 9, 2001Date of Patent: November 16, 2004Assignee: Nano Or Technologies Inc.Inventors: Yoel Arieli, Shay Wolfling, Eyal Shekel
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Patent number: 6809829Abstract: A lens evaluation method includes diffracting light derived from a lens so that two diffracted rays of different orders (e.g., a 0th-order diffracted ray and a +1st-order diffracted ray) interfere with each other, thereby obtaining a shearing interference figure, and changing phases of the diffracted rays. The method also includes in the shearing interference figure, determining phases of light intensity changes at a plurality of measuring points on a measuring line which passes through a midpoint of a line segment interconnecting optical axes of the two diffracted rays, and determining characteristics (defocus amount, coma, astigmatism, spherical aberration and a higher-order aberration) of the lens based on the phases.Type: GrantFiled: May 18, 2000Date of Patent: October 26, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kazumasa Takata, Masahiro Nakajo, Kanji Nishii
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Patent number: 6809307Abstract: A beam control system and method which utilizes the wavefront reversal property of nonlinear optical phase conjugation to permit incorporation of a liquid crystal OPA within the low power legs of the beam control system, thereby affording the advantages of the OPA without the power limitations thereof. The invention is adapted for use with a beacon for illuminating a target with a first beam of electromagnetic energy. The system includes a telescope (1010) for receiving a target return comprising a reflection of the first beam from the target. An optical phased array (1050) is included for correcting for aberrations in the wavefront of the target return. A mechanism is included for ascertaining the correction applied by the optical phased array to the target return. The mechanism applies the correction to a third beam which ultimately is the output beam.Type: GrantFiled: September 28, 2001Date of Patent: October 26, 2004Assignee: Raytheon CompanyInventors: Robert W. Byren, Alvin F. Trafton
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Patent number: 6806964Abstract: An optical recording and/or reproduction apparatus includes: a light source for emitting a first light beam; an optical system for outputting first and second diffracted light beams and a second light beam; and a controlling section for controlling the optical system, wherein the first and second diffracted light beams interfere with each other to generate interference fringes which extend in a direction substantially perpendicular to a recording layer of an recording medium, the optical recording and/or reproduction apparatus further includes a detection section for detecting the interference fringes reflected by the guiding portion so as to output a detection signal, and the control section controls the optical system based on the detection signal such that the optical spots follow at least either of concave portions and convex portions of the guiding portion.Type: GrantFiled: May 29, 2002Date of Patent: October 19, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroaki Yamamoto, Teruhiro Shiono, Tetsuo Saimi
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Patent number: 6804009Abstract: A Wollaston prism phase-stepping point diffraction interferometer for testing a test optic. The Wollaston prism shears light into reference and signal beams, and provides phase stepping at increased accuracy by translating the Wollaston prism in a lateral direction with respect to the optical path. The reference beam produced by the Wollaston prism is directed through a pinhole of a diaphragm to produce a perfect spherical reference wave. The spherical reference wave is recombined with the signal beam to produce an interference fringe pattern of greater accuracy.Type: GrantFiled: February 28, 2002Date of Patent: October 12, 2004Assignee: The Regents of the University of CaliforniaInventor: Michael C. Rushford
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Patent number: 6795198Abstract: The invention provides both a method and apparatus that measures a property of a structure that includes at least one layer. The apparatus features a laser (e.g., a microchip laser, described below) that generates an optical pulse, and a diffractive mask that receives the optical pulse and diffracts it to generate at least two excitation pulses. An optical system, (e.g., an achromat lens pair) receives the optical pulses and spatially and temporally overlaps them on or in the structure to form an excitation pattern that launches an acoustic wave. The acoustic wave modulates a property of the structure, e.g., it generates a time-dependent “surface ripple” or modulates an optical property such as the sample's refractive index or absorption coefficient. Surface ripple is defined as a time-dependent change in the morphology of the surface; its peak-to-null amplitude is typically a few angstroms or less.Type: GrantFiled: May 28, 1998Date of Patent: September 21, 2004Inventors: Martin Fuchs, Matthew J. Banet, Keith A. Nelson, John A. Rogers
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Publication number: 20040174536Abstract: The invention relates to an optical device (2) for characterising a diffraction grating (14) which is formed by first and second interferometric diffractive sensors (4, 6) which are integral, spaced apart from each other at a determined first distance, and each comprise a reading grating (10a, 10b) and at least one light intensity detector, these first and second sensors providing respectively first and second electrical signals which, during a relative displacement (&Dgr;x) between the device and the diffraction grating, vary as a function of the spatial frequency of this grating in first and second regions of the latter, which regions are located respectively opposite two reading gratings and each receive light supplied by at least one light source. In particular, the first and second electrical signals define first and second phases of the first and second sensors.Type: ApplicationFiled: April 22, 2004Publication date: September 9, 2004Inventors: Yves Jourlin, Olivier Parriaux, Marc Andre Pierre Bonis
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Publication number: 20040174533Abstract: An aberration measuring apparatus capable of measuring wavefront aberration at a high degree of accuracy regardless of the magnitude of aberration of an optical system is disclosed. This aberration measuring apparatus includes a first mask which generates a wavefront including wavefront aberration of the optical system and a reference wavefront not including wavefront aberration of the optical system with respect to a predetermined direction, a second mask which generates two wavefronts, both of which include wavefront aberration of the optical system and a detector placed at a position where the two wavefronts generated by the first mask or the two wavefronts generated by the second mask form an interference pattern. Wavefront aberration of the optical system is calculated based on the interference pattern detected by this detector.Type: ApplicationFiled: March 3, 2004Publication date: September 9, 2004Inventor: Akihiro Nakauchi
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Publication number: 20040169866Abstract: A wavefront measurement system includes a source of electromagnetic radiation. An imaging system directs the electromagnetic radiation at an object plane that it uniformly illuminates. A first grating is positioned in the object plane to condition the radiation entering the input of a projection optic. A projection optical system projects an image of the first grating onto the focal plane. A second grating is positioned at the focal plane that receives a diffracted image of the object plane to form a shearing interferometer. A CCD detector receives the image of the pupil of the projection optical system through the projection optical system and the second grating that forms a fringe pattern if there are aberrations in the projection optical system. Phaseshift readout of fringe pattern can be accomplished by stepping the first grating in a lateral direction and reading each frame with the CCD detector.Type: ApplicationFiled: January 5, 2004Publication date: September 2, 2004Applicant: ASML Holding, N.V.Inventor: Sherman K. Poultney
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Patent number: 6785001Abstract: An apparatus for detecting wavelength change of a first light signal comprises an amplitude splitting interferometer and a detector. The amplitude splitting interferometer comprises first and second optical paths. The first optical path has a first index of refraction that varies with wavelength over a first wavelength band. The second optical path has a second index of refraction that is relatively constant over the first wavelength band. In operation the first light signal enters and exits the amplitude splitting interferometer forming interference light. The interference light couples to the detector which detects the wavelength change of the first light signal from the interference light. An interferometer comprises a first beam splitter, third and fourth optical paths, and a second beam splitter. The third optical path is optically coupled to the first beam splitter and has a third index of refraction that varies with wavelength over a second wavelength band.Type: GrantFiled: August 21, 2001Date of Patent: August 31, 2004Assignee: Silicon Light Machines, Inc.Inventors: Kais Almarzouk, Dinesh Maheshwari
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Publication number: 20040165194Abstract: Characterization of an optical system is quickly and easily obtained in a single acquisition step by obtaining image data within a volume of image space. A reticle and image plane are positioned obliquely with respect to each other such that a reticle having a plurality of feature sets thereon, including periodic patterns or gratings, is imaged in a volume of space, including the depth of focus. Metrology tools are used to analyze the detected or recorded image in the volume of space through the depth of focus in a single step or exposure to determine the imaging characteristics of an optical system. Focus, field curvature, astigmatism, spherical, coma, and/or focal plane deviations may be determined. The present invention is particularly applicable to semiconductor manufacturing and photolithographic techniques used therein, and is able to quickly characterize an optical system in a single exposure with dramatically increased data quality and continuous coverage of the full parameter space.Type: ApplicationFiled: February 26, 2004Publication date: August 26, 2004Inventor: Matthew E. Hansen
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Patent number: 6781701Abstract: A method, apparatus, and system for measuring optical phase and amplitude properties of an output optical field to characterize diffractive, refractive, and other optical elements to estimate, measure, and characterize an optical transfer function are disclosed herein. In a representative embodiment, a light source may generate an optical field incident to an optical element, such as a diffraction grating. An aperture plate may be positioned relative to the optical element to allow translation of at least one of the aperture plate or the optical element in a plane transverse to a surface normal of the optical element, resulting in an output optical field having spatially dependant amplitude and phase characteristics related to a position on the optical element and to the optical field incident to the optical element. The output optical field may then be detected and analyzed to characterize the optical transfer function of the optical element.Type: GrantFiled: April 5, 2002Date of Patent: August 24, 2004Assignee: Intel CorporationInventors: John N. Sweetser, Anders Grunnet-Jepsen
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Patent number: 6781702Abstract: Techniques for determining large deformation of layered or graded structures to include effects of body forces such as gravity, electrostatic or electromagnetic forces, and other forces that uniformly distribute over the structures, support forces, and concentrated forces. A real-time stress monitoring system is also disclosed to provide in-situ monitoring of a device based on the large deformation analytical approach. A coherent gradient sensing module, for example, may be included in such a system.Type: GrantFiled: May 28, 2002Date of Patent: August 24, 2004Assignee: California Institute of TechnologyInventors: Antonios Giannakopoulos, Subra Suresh, Ares J. Rosakis, Ilan Blech
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Publication number: 20040160611Abstract: An interferometric optical device divides a beam into two beam portions by wavefront division and produces a tunable phase difference between them. Next a sample and a reference reflector reflect the beam portions respectively. Then interference between the reflected beam portions is used for topography, tomography, and readout of multi-layer optical data storage media.Type: ApplicationFiled: February 14, 2003Publication date: August 19, 2004Inventor: Chian Chiu Li
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Patent number: 6778275Abstract: An aberration mark for use in an optical photolithography system, and a method for estimating overlay errors and optical aberrations. The aberration mark includes an inner polygon pattern and an outer polygon pattern, wherein each of the inner and outer polygon patterns include a center, and two sets of lines and spaces having a different feature size and pitch that surround the outer polygon pattern. The aberration mark can be used to estimate overlay errors and optical aberrations. In some embodiments, the mark can also be used with scatterometry or scanning electron microscope devices. In other embodiments, the mark can be used to monitor aberrations of a lens in an optical photolithography system.Type: GrantFiled: February 20, 2002Date of Patent: August 17, 2004Assignee: Micron Technology, Inc.Inventor: Steve W. Bowes
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Patent number: 6775008Abstract: A scale (10) is illuminated by a light source (18). After interaction with an index grating (12), fringes (F) are formed in a Talbot plane and analyzed by an analyzer grating (14). To decrease the sensitivity to changes in the ride height of the index grating above the scale, the light source is restricted to a small but finite size, and positioned so that it subtends a small angle Ø at the analyzer grating (or, if a collimating lens (24) is used, positioned so that it subtends a small angle Ø at the lens). The size of the light source should preferably be smaller than a predetermined value such that the extent of a geometric fringe visibility envelope exceeds the extent of a Talbot fringe visibility envelope.Type: GrantFiled: October 12, 2001Date of Patent: August 10, 2004Assignee: Renishaw PLCInventor: Michael Homer
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Publication number: 20040150834Abstract: To measure a convex mirror, a reference beam and a measurement beam are both provided through a single optical fiber. A positive auxiliary lens is placed in the system to give a converging wavefront onto the convex mirror under test. A measurement is taken that includes the aberrations of the convex mirror as well as the errors due to two transmissions through the positive auxiliary lens. A second measurement provides the information to eliminate this error. A negative lens can also be measured in a similar way. Again, there are two measurement set-ups. A reference beam is provided from a first optical fiber and a measurement beam is provided from a second optical fiber. A positive auxiliary lens is placed in the system to provide a converging wavefront from the reference beam onto the negative lens under test. The measurement beam is combined with the reference wavefront and is analyzed by standard methods.Type: ApplicationFiled: January 23, 2004Publication date: August 5, 2004Applicant: The Regents of the University of CaliforniaInventors: Gary E. Sommargren, Eugene W. Campbell
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Patent number: 6771376Abstract: A sensor platform for use in sample analysis comprises a substrate (30) of refractive index (n1) and a thin, optically transparent layer (32) of refractive index (n2) on the substrate, (n2) is greater than (n1). The platform incorporates one or multiple corrugated structures in the form of periodic grooves (31), (33), which defines one or more sensing areas each for one or more capture elements. The grooves are so profiled, dimensioned and oriented that when coherent light is incident on the platform it is diffracted into individual beams or diffraction order resulting in reduction of the transmitted beam and an abnormal high reflection of the incident light thereby creates an enhanced evanescent field at the surface of the or each sensing area. The amplitude of this field at the resonant condition is greater by an order of approximately 100 than the field of prior art platforms so that the luminescence intensity created from samples on the platform is also increased by a factor of 100.Type: GrantFiled: January 10, 2002Date of Patent: August 3, 2004Assignee: Novartis AGInventors: Wolfgang Ernst Gustav Budach, Dieter Neuschaefer
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Publication number: 20040145752Abstract: A fast, accurate and reliable sensor applicable to chemical and biological analytes resides in an optical grating-based sensor, sensing system, and method of use. The sensor, configured for use with an illumination source and a signal detector in the system embodiment, includes first and second periodic diffraction gratings superimposed and shifted laterally relative to each other by a distance of less than one period, such that the illumination from the source is affected by both gratings before reaching the detector. An analyte recognition material disposed on a surface of the second diffraction grating. In operation, the output of the detector is first used to establish a baseline optical phase signal. The analyte recognition material is exposed to a sample, and the output of the detector is used to to determine a second optical phase signal. The baseline optical phase signal is compared to the second optical phase signal to detect the presence of the analyte, if any, in the sample.Type: ApplicationFiled: January 24, 2003Publication date: July 29, 2004Inventor: David Angeley
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Patent number: 6765681Abstract: The phase (and amplitude) of a wave front may be accurately measured using knowledge of the wave front of an optical field generated by an optical element, permitting the determination of the spatial transfer function of that optical element. As a device under test is scanned across an aperture plate having slits, variations in the relative amplitude and phase of light passing through the slits are affected by the optical properties of the device under test, in turn affecting the interference pattern at a detector. Changes in the amplitude and phase of the detected signal are directly and uniquely related to the transfer function of the device under test.Type: GrantFiled: April 10, 2002Date of Patent: July 20, 2004Assignee: Intel CorporationInventors: John N. Sweetser, Anders Grunnet-Jepsen
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Patent number: 6765683Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.Type: GrantFiled: August 13, 2002Date of Patent: July 20, 2004Assignee: Nikon CorporationInventor: Hiroshi Ichihara
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Patent number: 6762839Abstract: A system and method for performing selected optical measurements on a sample is provided utilizing an optical coherence domain reflectometer which includes a diffraction grating. A broad band light source produces light having a short coherence length. A beamsplitter splits the light into a signal beam and a reference beam. A reference mirror is disposed to receive the reference beam. A lens brings the signal beam to focus on the sample. A diffraction grating receives reflections from the sample and from the reference mirror, the reflections being incident on the diffraction grating with respect to said diffraction grating normal such that a positive diffraction order from one of the reflections and a negative diffraction order from the other one of the reflections and a negative diffraction order from the other one of the reflections propagate along a common path.Type: GrantFiled: July 22, 2002Date of Patent: July 13, 2004Assignee: Research Foundation of City College of New YorkInventors: Iosif Zeylikovich, Robert R. Alfano
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Patent number: 6753969Abstract: The present invention relates to microinterferometers. An embodiment of a microinterferometer for accurately measuring the distance to an object surface includes a substrate and a tunable, phase-sensitive, reflective diffraction grating formed atop said substrate. The diffraction grating is configured to reflect a first portion of an incident light and transmit a second portion of the incident light, such that the second portion of the incident light is diffracted. The diffraction grating is further configured to be controllably adjusted. The microinterferometer also includes a photo-detector for receiving interference patterns produced from the first portion of the incident light reflected from the diffraction grating and the second portion of the incident light reflected from the object surface. The microinterferometer also includes a controller coupled to the photo-detector and the diffraction grating for adjusting the diffraction grating, such that the interference patterns are altered.Type: GrantFiled: March 29, 2002Date of Patent: June 22, 2004Assignee: Geogia Tech Research CorporationInventors: Fahrettin L. Degertekin, Thomas R. Kurfess, Byungki Kim, Hosein Ali Razavi
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Publication number: 20040109168Abstract: The interferometer has a diffraction grating 21, a condenser lens 22, a transparent substrate 23, a field lens 24 and an imaging device 25 arranged in this order. The transparent substrate 23 is arranged at the position in the optical axis direction where both focal spots of a zeroth-order diffracted light L21 and a first-order diffracted light L22 are formed. Formed on the transparent substrate 23 is a circular opaque zone 23a whose central position is the central position of the focal spot of the first-order diffracted light L22. Formed at the center of the opaque zone 23a is a pinhole 23b whose central position is the central position of the focal spot of the first-order diffracted light L22. The contrast of the interference fringes observed on the image device 25 is enhanced by the optical interference between the first-order diffracted light L22 passing through the pinhole 23b and the zeroth-order diffracted light L21 passing through the transparent substrate 23.Type: ApplicationFiled: December 2, 2003Publication date: June 10, 2004Inventor: Kenji Fukui
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Patent number: 6744520Abstract: A method for measuring two-dimensional displacement using conjugate optics comprises the steps of emitting an incident beam onto a diffraction element to generate many firstly diffracted beams, selecting two axially symmetric beams of the same order of diffraction from the firstly diffracted beams, introducing corresponding sets of wavefront reconstruction optics to reflect the two selected beams back onto the same incident spot along the same optical paths and to generate many secondly diffracted beams, selecting two axially symmetric pairs of beams of the same order of diffraction from the secondly diffracted beams, forming two interference fringes by superposing the two selected pairs of beams via corresponding mirrors and interferometric optics, and obtaining two linearly independent displacements of the diffraction element relative to the rest of the optics by decoding the two interference fringes.Type: GrantFiled: March 4, 2002Date of Patent: June 1, 2004Assignee: Industrial Technology Research InstituteInventors: Chung-Chu Chang, Ching-Fen Kao, Chih-Kung Lee
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Publication number: 20040070769Abstract: The present invention relates to an apparatus for the determination of a condition or state of an object based on quasi-elastic interaction between the object and light transmitted to the object, the apparatus comprising a diffractive optical element having a diffracting region comprising a first diffracting structure for diffraction and focussing of a first light beam to the object, and a second diffracting structure that is laterally displaced relative to the first diffracting structure for diffraction and focussing of a second light beam to the object. The first and second diffracting structures focus the first and second light beams in the same focussing plane, the focussing plane being substantially perpendicular to propagation directions of the first and second light beams. The diffracting region further comprises a receiving diffracting structure for diffraction of light from the light beams that has interacted with the object. The diffracted light is diffracted in a diffraction angle.Type: ApplicationFiled: July 3, 2003Publication date: April 15, 2004Inventor: Carsten Dam-Hansen
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Patent number: 6717682Abstract: A wavelength detector includes an optical structure receiving an input beam, the optical structure outputting at least three wavelength dependent two-beam interference signals. Each wavelength dependent two-beam interference signal has a different phase offset. A detector receives the at least three wavelength dependent two-beam interference signals and outputs an electrical signal representative of each wavelength dependent two-beam interference. A processor receives the at least three electrical signals from the detector and generates a composite control signal. Alternatively, two of the three signals are periodic with respect to wavelength and the third signal is a reference signal. The two-beam interference signals may be created by providing patterned apertures in respective beam paths. Phase shifting interferometry techniques may be used to determine the wavelength from the periodic signals.Type: GrantFiled: December 28, 2001Date of Patent: April 6, 2004Assignee: Digital Optics Corp.Inventors: Alan D. Kathman, Robert Russell Boye
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Publication number: 20040061866Abstract: The invention uses the phase shifting diffraction interferometer (PSDI) to provide a true point-by-point measurement of absolute flatness over the surface of optical flats. Beams exiting the fiber optics in a PSDI have perfect spherical wavefronts. The measurement beam is reflected from the optical flat and passed through an auxiliary optic to then be combined with the reference beam on a CCD. The combined beams include phase errors due to both the optic under test and the auxiliary optic. Standard phase extraction algorithms are used to calculate this combined phase error. The optical flat is then removed from the system and the measurement fiber is moved to recombine the two beams. The newly combined beams include only the phase errors due to the auxiliary optic. When the second phase measurement is subtracted from the first phase measurement, the absolute phase error of the optical flat is obtained.Type: ApplicationFiled: September 27, 2002Publication date: April 1, 2004Applicant: The Regents of the University of CaliforniaInventor: Gary E. Sommargren
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Publication number: 20040051878Abstract: A multi-aperture interferometric optical system collects light propagating from a source of light and develops overlapping diffraction patterns on an optical detector that produces output signals for processing to form an image corresponding to the diffraction patterns. A preferred embodiment of the invention is a large aperture orbiting, earth-watching ring interferometric optical system configured such that there is no macro-structure pointing. Four mirror-ring structures direct incoming light to a multi-spectral primary optical detector that acquires light-pattern information from which an image can be derived.Type: ApplicationFiled: June 20, 2003Publication date: March 18, 2004Inventor: Geoffrey B. Rhoads
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Patent number: 6707560Abstract: The phase-shifting point diffraction interferometer (PS/PDI) was developed to address the problem of at-wavelength metrology of extreme ultraviolet (EUV) optical systems. Although extremely accurate, the fact that the PS/PDI is limited to use with coherent EUV sources, such as undulator radiation, is a drawback for its widespread use. An alternative to the PS/PDI, with relaxed coherence requirements, is lateral shearing interferometry (LSI). The use of a cross-grating, carrier-frequency configuration to characterize a large-field 4×-reduction EUV lithography optic is demonstrated. The results obtained are directly compared with PS/PDI measurements. A defocused implementation of the lateral shearing interferometer in which an image-plane filter allows both phase-shifting and Fourier wavefront recovery. The two wavefront recovery methods can be combined in a dual-domain technique providing suppression of noise added by self-interference of high-frequency components in the test-optic wavefront.Type: GrantFiled: August 4, 2000Date of Patent: March 16, 2004Assignee: The Regents of the University of CaliforniaInventors: Patrick P. Naulleau, Kenneth Alan Goldberg
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Patent number: 6707561Abstract: A sensor platform for use in sample analysis comprises a substrate (30) of refractive index (n1) and a thin, optically transparent layer (32) of refractive index (n2) on the substrate, (n2) is greater than (n1). The platform incorporates one or multiple corrugated structures in the form of periodic grooves (31), (33), which defines one or more sensing areas each for one or more capture elements. The grooves are so profiled, dimensioned and oriented that when coherent light is incident on the platform it is diffracted into individual beams or diffraction order resulting in reduction of the transmitted beam and an anormal high reflection of the incident light thereby creates an enhanced evanescent field at the surface of the or each sensing area. The amplitude of this field at the resonant condition is greater by an order of approximately 100 than the field of prior art platforms so that the luminescence intensity created from samples on the platform is also increased by a factor of 100.Type: GrantFiled: July 5, 2000Date of Patent: March 16, 2004Assignee: Novartis AGInventors: Wolfgang Ernst Gustav Budach, Dieter Neuschaefer
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Patent number: 6671054Abstract: Production of interference patterns from incoherent light sources by using an optical filter, a field mirror, and a plane mirror. The optical filter is designed to filter incoherent light waves and generate coherent light waves. The field mirror is arranged to convert the coherent light waves into plane waves. The plane mirror is arranged as a Lloyd's mirror to generate interference patterns from the plane waves.Type: GrantFiled: February 7, 2002Date of Patent: December 30, 2003Assignee: Intel CorporationInventor: Michael Goldstein
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Publication number: 20030215053Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.Type: ApplicationFiled: June 16, 2003Publication date: November 20, 2003Applicant: NIKON CORPORATIONInventor: Yutaka Ichihara
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Patent number: 6650421Abstract: In an interferometer for detecting interference light between light flux passed through an object to be inspected and reference light to be generated from a portion of the light flux passed therethrough, a phase of the interference light is detected with high precision. The light flux passed through the optical system to be inspected forms a spot image on a pinhole formed in a plate. Measuring light from the spot image and the reference-light diffracted out of the light flux from the spot image at the pinhole create interference light which in turn is received by an observation system. An image of interference fringes formed by the interference light is taken with an image pickup element. Further, heterodyne interference light is created by vibrating the plate in the direction intersecting the light flux or in the direction along the light path of the light flux, thereby detecting a phase of each portion of the interference fringes with high precision.Type: GrantFiled: April 26, 2001Date of Patent: November 18, 2003Assignee: Nikon CorporationInventor: Nobutaka Magome
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Patent number: 6641268Abstract: An interference projection system for use with lithography using quasi-coherent sources, which has a non-diffractive beam splitting module and a non-diffractive module to cause interference of two or more beams, the modules combining to form interfering beams having the same orientation on a target surface. Two etalons are used to split a beam, to form two beams of the same orientation, strength and polarization. One or more pairs of mirrors cause the beam to interfere.Type: GrantFiled: November 26, 2001Date of Patent: November 4, 2003Assignee: Massachusetts Institute of TechnologyInventors: Theodore M. Bloomstein, Michael Switkes, Mordechai Rothschild
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Patent number: 6643025Abstract: Several embodiments of a microinterferometer are disclosed. A first embodiment of a microinterferometer for measuring the absolute distance to an object surface includes a substrate. The microinterferometer also includes a phase-sensitive, reflective diffraction grating formed on the substrate. The diffraction grating is configured to reflect a first portion of an incident light and transmit a second portion of the incident light, such that the second portion of the incident light is diffracted. The microinterferometer further includes a lens formed on the substrate for focusing the second portion of the incident light to a predetermined local distance, and a photo-detector for receiving interference patterns produced from the first portion of the incident light reflected from the diffraction grating and the second portion of the incident light reflected from the object surface.Type: GrantFiled: March 29, 2002Date of Patent: November 4, 2003Assignee: Georgia Tech Research CorporationInventors: Fahrettin L. Degertekin, Thomas R. Kurfess, Byungki Kim, Hosein Ali Razavi
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Patent number: 6639683Abstract: A method and device is capable of amplitude, phase, polarization shear, wavelength, and diversity measurement along a common path by using a sampling device to get a sparse sampled optical field. The sampled field is fed to a diversity generator device. The diversity generator device generates the diversity information associated with each sample/element of the sparse input in empty space provided by sampling. The diversity information may consist of phase-shifted copies of the input sample having known/device dependent relative phases, amplitudes, polarization, shear, or wavelength with respect to their originating sample. The geometry of the fan out allows overlap between part or all different diversity copies (originating from the same or from different samples) thus making the method interferometric.Type: GrantFiled: October 17, 2000Date of Patent: October 28, 2003Inventors: Remy Tumbar, David J. Brady
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Patent number: 6631047Abstract: An apparatus having a first system for forming a composite light beam of two light beams to be made to interfere with each other, a splitting member for amplitude-splitting the composite light beam into three or more split light beams in the same area, and a second system for obtaining interference light beams of different phases from the plurality of split light beams.Type: GrantFiled: September 18, 1998Date of Patent: October 7, 2003Assignee: Canon Kabushiki KaishaInventors: Kou Ishizuka, Hidejiro Kadowaki, Naoki Kawamata, Hiroyuki Hagiwara, Makoto Takamiya, Shigeki Kato, Hiroyuki Shiomi
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Publication number: 20030169430Abstract: There is provided a shape measuring apparatus using an interferometer comprising a lens for condensing temporarily light waves from a light source, and a light wave shaping plate having a pinhole with suitable size adapted to convert the condensed light waves into an ideal spherical wave and a window provided in the vicinity of the pinhole and having enough size to pass therethrough light wave surface information, in which at least one lens having a reference surface and a surface to be measured the optical axes of which are slightly decentered in an optical path of the light waves passed through the pinhole is arranged in a position where the light waves which are made incident perpendicularly to the reference surface to be reflected therefrom pass through the pinhole again, and the light reflected from the surface to be measured pass through the window, and the reflected light reflected by the reference surface to pass through the pinhole again and the reflected light reflected by the surface to be measuredType: ApplicationFiled: February 27, 2003Publication date: September 11, 2003Applicant: Canon Kabushiki KaishaInventors: Masaru Ohtsuka, Seiichi Kamiya, Hitoshi Iijima
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Patent number: 6600565Abstract: Methods and systems for evaluating stresses in line features formed on substrates. Stresses may be computed from measured curvature information based on simple analytical functions. The curvature information can be obtained optically by, e.g., a coherent gradient sensing method, to obtain a full-field measurement of an illuminated area.Type: GrantFiled: April 27, 2000Date of Patent: July 29, 2003Assignee: California Institute of TechnologyInventors: Subra Suresh, Ares J. Rosakis