Abstract: An improved condition testing system and method integrated into microelectronic circuits includes a structure including a semiconductor material with a target portion and a second portion for determining the presence and nature of various external (e.g. magnetic field, microwave, bioelectric or incident radiation) or internal stresses (e.g. binary circuit-state or analog signal recognition) or conditions acting upon the material. The target portion has a first feature when at least one of the following occurs: an external force is received by the second portion of the structure and an internal condition occurs in the target portion. The system and method further has a test grating determined and shaped and located to produce a first optical interference pattern when the target portion and the grating are exposed to non-invasive illumination and when the target portion has the first feature.

Abstract: Provided is a method for focusing a workpiece in the Z-axis for optical metrology. The auto focusing subsystem includes a focus detector having a tilt angle, a capture range, and a plurality of sensors. A processor coupled to the focus detector is configured to utilize the plurality of focus signals measured using the focus detector to determine two or more focus parameters. The two or more focus parameters and calibration data are used to determine an initial position of the workpiece and to generate instructions to move the workpiece to a best focus position.

Abstract: A measurement apparatus comprises a mirror configured to reflect test light which passes through an optical system, an interferometer unit which includes an image sensor and is configured to form an interference fringe on an image sensing plane of the image sensor by reference light and the test light reflected by the mirror, and a controller configured to control the interferometer unit, and to compute a numerical aperture of the optical system based on the interference fringe captured by the image sensor, wherein the controller is configured to compute a numerical aperture NA of the optical system by multiplying a quotient ?NA/?R, describing a change ?NA in numerical aperture NA of the optical system with respect to a change ?R in pupil radius R of the optical system in the image sensing plane, by the pupil radius R of the optical system in the image sensing plane.

Abstract: A method comprises determining a first processing center position to calculate a wavefront aberration of an optical system, determining a second processing center position to calculate a wavefront aberration, correcting the first processing center position in a first direction using the second processing center position in the first direction and correcting the second processing center position in a second direction using the first processing center position in the second direction.

Abstract: A multi-conjugate adaptive optics system is described that reduces aberration-induced fluctuations of amplitude and phase in a beam without requiring the explicit measurement and feedback control of the beam's irradiance profile. The system uses a pair of wavefront correctors conjugated to widely separated planes in a turbulent path, where each of the wavefront correctors is controlled by a decentralized wavefront control loop. The system is configured such that the explicit control of phase fluctuations in a beam using the pair of wavefront correctors results in the implicit control of amplitude fluctuations in the beam. Because the system uses decentralized control loops that do not rely on beam irradiance measurement and feedback, the complexity of the control loop is reduced below that of conventional multi-conjugate adaptive optics systems and is comparable to that of single-conjugate adaptive optics systems.

Abstract: An apparatus rapidly reads out wavefront errors of an input wavefront and includes a holographic optical element (HOE), a position readout detector and a readout device. The HOE receives the input wavefront and includes a hologram of a particular wavefront recorded with reference waves, each defining a particular aberration coefficient. The position readout detector includes a plurality of position sensing devices (PSDs) receiving an optical output of the HOE, each PSD sensing the occurrence and magnitude in the input wavefront of any of the particular aberrations defined by the reference waves recorded to the holographic optical element with the particular wavefront. The readout device provides a readout value of each PSD upon application of the input wavefront to the holograph optical element, each readout value representing in the input wavefront the presence and magnitude of any of the particular aberrations defined by the reference waves.

Abstract: A method is disclosed for producing projective and tomographic phase contrast images of an examination object, preferably a patient, with the aid of an X-ray system, and a corresponding X-ray system for carrying out this method. In at least one embodiment of the method, X-ray optical grating sets tuned to different energy ranges are used to determine energy-dependent phase shifts upon penetration of an examination object, a difference value is formed from these energy-dependent phase shifts, and tomographic or projective images are produced therefrom.

Abstract: Methods and apparatus to perform wavefront analysis, including phase and amplitude information, and 3D measurements in optical systems, and in particular those based on analyzing the output of an intermediate plane, such as an image plane, of an optical system. Measurement of surface topography in the presence of thin film coatings, or of the individual layers of a multilayered structure is described. Multi-wavelength analysis in combination with phase and amplitude mapping is utilized. Methods of improving phase and surface topography measurements by wavefront propagation and refocusing, using virtual wavefront propagation based on solutions of Maxwell's equations are described. Reduction of coherence noise in optical imaging systems is achieved by such phase manipulation methods, or by methods utilizing a combination of wideband and coherent sources.

Abstract: The present invention provides a method including measuring a wavefront aberration of the optical system to be measured on a measurement surface, measuring a pupil transmittance distribution of the optical system determining a pupil function of the optical system based on the wavefront aberration and the pupil transmittance distribution, and performing imaging computation using the pupil function to obtain a light intensity distribution formed on an image plane of the optical system, and calculating a flare, generated in the optical system, from the light intensity distribution.

Abstract: A phase shift amount measurement apparatus able to further correctly measure a phase shift amount of a phase shifter, wherein a laterally offset interference image of a phase shift mask is formed by a shearing interferometer, the interference image is captured by a two-dimensional imaging device, an output signal output from each light receiving element of the two-dimensional imaging device is supplied to a signal processing device, the phase shift amount is calculated for each light receiving element, the light receiving area of the light receiving element is very small, therefore the phase shift amount of any light receiving element outputting a peculiar phase amount due to incidence of diffraction light or multi-reflection light is excluded and the phase shift amount is determined based on the phase shift amount found from output signals of the remaining light receiving elements.

Abstract: A microscope which has a high three-dimensional resolution, does not require specimens to be stained and is easy to operate, is presented. The three-dimensional microscope includes a first optical system for illuminating an object with lights in a plurality of illuminating directions, one direction after another; an imaging section; a second optical system for guiding diffracted lights generated by the object and reference lights to the imaging section that obtains interference images of the diffracted lights and the reference lights; and a processor for generating a three-dimensional image using the interference images for respective illuminating directions, obtained by the imaging section. The processor obtains complex amplitudes of the diffracted lights from the interference images for respective illuminating directions and generates the three-dimensional image of the object from the complex amplitudes.

Abstract: An apparatus in one example has: first and second Fourier transform lenses, the first Fourier transform lens receiving an incident plane wavefront and focusing the plane wavefront down to a focal point in a focal plane, and the second Fourier transform lens reimaging the focused down plane wavefront to an output plane wavefront; a bead located substantially at the focal point and that is illuminated by radiation that comes in from the first lens, the bead reradiating a spherical wave, which interferes with light that passes around the bead to produce a diffraction pattern; an array of controllable light transmissive elements that support the bead in the focal plane; and a null seeking servomechanism for assigning an electrical value of phase departure of the incident plane wavefront from a reference thereof, the null seeking servomechanism controlling the light transmissive elements to produce phase shifts in light that passes around the bead to thereby remove aberrations in the incident plane wavefront.

Abstract: The present invention provides a measurement apparatus which measures a wavefront aberration of a measurement target optical system, the apparatus including a fringe scanning unit configured to perform fringe scanning by changing a phase difference between test light and reference light, a determination unit configured to determine a nonlinear error representing a nonlinear change in feature amount, which is derived from an interference pattern between the test light and the reference light, with respect to predetermined control data by performing fringe scanning by the fringe scanning unit in accordance with the control data in a plurality of phase states, and a correction unit configured to correct, based on the nonlinear error determined by the determination unit, a wavefront aberration of the measurement target optical system calculated from the interference pattern between the test light and the reference light.

Abstract: An optical system representing the configuration of a tested element disposed therein is provided. The optical system comprises a light source emitting a spatial-incoherent light having a phase shifting scheme toward the tested element and then forming an image with a transverse ray aberration on the image plane of the tested element; a spatial filter on the image plane to spatially filter the image formed by the tested element; and a detection module comprising a detector for receiving the spatially filtered image.

Abstract: A measuring apparatus includes a pinhole mask, located at an object plane of an optical system to be measured, and having a plurality of pinholes for generating a spherical wave from a measuring light beam, and a diffraction grating for splitting the measuring light beam that has passed the pinhole mask and the optical system, wherein Lg=m·Pg2/? is met, where Pg is a grating pitch of the diffraction grating, ? is a wavelength of the measuring light beam, m is an integer other than zero, and Lg is a distance between the diffraction grating and an image plane of the optical system. The measuring apparatus calculates a wavefront aberration of the optical system from an interferogram formed by causing interference of the measuring light beams split by the diffraction grating.

Abstract: A measuring device for measuring a wavefront aberration of an optical system includes a first mask for defining light that enters the optical system, and a second mask having first to fourth openings. The first opening transmits a component of the light passing through the optical system without removing information about the wavefront aberration of the optical system, and the second to fourth openings transmit components of the light passing through the optical system having the information about the wavefront aberration of the optical system removed.

Abstract: An optical encoder which is designed to convert light generated from a light source into parallel light rays by using a collimator lens, thereby allowing the collimated light to radiate to gratings (a first grating, a second grating and a third grating). A diffusing element (a diffusion plate or a diffusion surface) is provided between the light source and the collimator lens to mitigate the parallelization degree of light, thereby weakening the second-order and the third-order or high-order diffraction light. Consequently, even where a light emitting diode (LED) or laser diode (LD) is used as the light source, a favorable interference output can be obtained.

Abstract: A measurement apparatus which measures spatial coherence in an illuminated plane illuminated by an illumination system, comprises a measurement mask which has at least three pinholes and is arranged on the illuminated plane, a detector configured to detect an interference pattern formed by lights from the at least three pinholes, and a calculator configured to calculate the spatial coherence in the illuminated plane based on a Fourier spectrum obtained by Fourier-transforming the interference pattern detected by the detector.

Abstract: An apparatus for measuring the axial length of a human eye, the apparatus comprising a low coherence light source; a beam splitter; a fast displacement module for rapidly varying the path length within a reference arm of an interferometer; a laser directing a laser beam that is co-propagating with light from the low coherence light source into the displacement module.

Abstract: An optical system includes a substrate adapted for supporting a sample, where the substrate has a refractive index, nsub, larger than a refractive index of the sample, nsample, a source of electromagnetic radiation having wavelength, ?o, and a detector having multiple individual detector elements configured for detecting a signal resulting from an interaction of the electromagnetic radiation with the sample. The system includes dividing optics, directing optics, and control optics. The dividing optics are configured for dividing the electromagnetic radiation from the source into at least three substantially independent excitation beams.

Abstract: A method and device realize shallow gratings-based planar beam splitter/combiner. Non-trivial phase shifts between different ports of resulting interferometers are used to acquire full-field phase measurements. The non-trivial phase shifts between different ports of the planar beam splitter/combiner can be adjusted by simply shearing one grating with respect to the second grating. The two shallow diffraction gratings are harmonically-related and can be recorded on a single substrate for compact interferometric based schemes. During the recording process, the two gratings are aligned such that the grating planes and the grating vectors are parallel to that of each other. The relative phase of the recording beams controls the shearing between the recorded harmonically-related shallow phase gratings. The relative shearing of the two gratings defines the non-trivial phase shift between different ports of the compact planar beam splitter/combiner.

Abstract: The application relates to a method for analyzing the wave surface of a light beam from a source to the focus of a lens. The beam illuminates a sample on the analysis plane and having a defect. A diffraction grating of the plane is a conjugate of an analysis plane through a focal system. An image is formed in a plane at a distance from the grating plane and analyzed by processing means. The invention encodes this grating by a phase function resulting from the multiplication of two phase functions, a first exclusion function defining a meshing of useful zones transmitting the beam to be analyzed in the form of light pencil beams, and a second phase fundamental function which creates a phase opposition between two light pencil beams coming out of adjacent meshes of the exclusion grating.

Abstract: A method of positioning optical elements relative to each other uses an interferometer apparatus comprising a plurality of holograms generating beams of adjustment measuring light which are incident on optical surfaces of the optical elements. Interference patterns generated by superimposing adjustment measuring light of the beams reflected from the surfaces are indicative of positioning errors of the optical elements. The beams of adjustment measuring light may comprise focused beams forming a point focus on the optical surface and beams of light which is orthogonally incident on extended portions on the optical surface.

Abstract: Described is an interferometric surface contour measurement system for projecting structured light patterns onto an object. The measurement system includes an interferometric projector, an imager, and a processor. The imager is rigidly coupled to the projector to maintain a stable relationship to the projected, structured light pattern. The imager receives the structured light pattern and together with the processor, determines whether the projected image includes a positional error. In some embodiments, the projector is a multi-channel projector, each channel having an optical axis spatially separated from the others, one of the channels including the imager and dedicated for determining positional error. In other embodiments, the projector is a single-channel projector projecting a structured light pattern onto the object, a portion of the structured light pattern being tapped-off for determining positional error.

Abstract: Described are a multiple channel interferometric surface contour measurement system and methods of determining surface contour data for the same. The measurement system includes a multiple channel interferometer projector, a digital camera and a processor. Fringe patterns generated by spatially separate channels in the projector are projected onto an object surface to be measured. The digital camera acquires images of the fringe patterns and the processor determines surface contour data from the fringe patterns. More specifically, fringe numbers are determined for points on the object surface based on image data. The fringe numbers are modified according to collinear adjustment values so that the modified fringe numbers correspond to a common, collinear axis for the interferometer projector. After unwrapping the modified fringe numbers, the unwrapped values are modified by the collinear adjustment values to obtain accurate fringe numbers for the pixels in each interferometer channel.

Abstract: The present invention provides a measurement method of measuring a wavefront aberration of an optical system to be measured, the method including arranging a measurement reticle on an object plane of the optical system to be measured, forming an image of the wavefront measurement mark on an image plane of the optical system to be measured, and calculating the wavefront aberration based on a position shift amount of the image of the wavefront measurement mark from an ideal position, the image being formed on the image plane of the optical system to be measured, wherein the wavefront measurement mark includes a first mark having a longitudinal direction in a first direction, and a second mark having a longitudinal direction in a second direction perpendicular to the first direction and spaced apart from the first mark.

Abstract: A wavefront aberration measuring device includes a mask placed in an object plane of a to-be-tested optical system and having a pattern including a pinhole producing a spherical wave and adjoining diffraction gratings each ruled with lines oriented in a direction different from the other; an illumination optical system that illuminates an area of the mask with light emitted from a light source; a light splitter that splits the light from the pattern transmitted through the to-be-tested optical system; an image pickup unit that takes an image of interference fringes produced by the split light, the image being used in measuring wavefront aberration of the to-be-tested optical system; a detector that detects respective light quantities of respective diffracted beams from the respective illuminated diffraction gratings; and a control unit that controls alignment of the illuminated area of the mask and the pattern in accordance with a detection result.

Abstract: A method of restoring low spatial frequency spectral information to an image using a Fizeau Fourier transform spectrometer (“FFTS”) system is provided. Portions of a wavefront collected by the FFTS are interfered. The interference patterns are Fourier transformed to generate spectral images. A region of the image is identified, for which spectral information is predetermined. Object estimates are generated, each of which corresponds to a spectral image. Each object estimate is iteratively adjusted applying a system spectral optical transfer function (“SOTF”) to it and modifying it until a match is made with the corresponding spectral image. Each adjusted object estimate is then iteratively restored by applying a system optical transfer function (“OTF”) to it and then applying a DC bias to it until a match is made between the identified region in the sum of the object estimates and the identified region of a measured panchromatic object image.

Abstract: The present invention relates to a large area undistorted imaging apparatus for light speckles and a method thereof. The large area undistorted imaging apparatus for light speckles comprises a light-emitting device, a light-limiting module, and a sensor. The light-limiting module is adapted in front of the sensor, and includes a plurality of light-limiting members. The light-limiting members are arranged in a one- or two-dimensional array. When the light-emitting device emits light to an object surface, one or more rays of scattered light are produced. By means of the light-limiting module, said one or more rays of scattered light are limited, and a plurality of rays of diffraction light is produced. The plurality of rays of diffraction light within a certain angular field of view produced by a light-limiting member interferes with each other and produces a plurality of undistorted light speckles, and forms an array of light-speckle images on the sensor.

Abstract: A measurement apparatus which measures a wavefront aberration of an optical system to be measured, the apparatus comprises a detection unit configured to detect an interference pattern formed by light having passed through a mask inserted on an object plane of the optical system to be measured, and a mask inserted on an image plane of the optical system to be measured.

Abstract: A wave front control system (“WFCS”) organizes the object scene into a mosaic comprised of a grid of segments and transmits each segment in a temporal sequence. The WFCS steers the light fronts emanating from each segment one segment at a time, through a series of optical components that transmit the light fronts respectively emanating from each segment onto a digital imaging sensor. An optical recording device records each sensed segment, and the object scene is composed by assembling the recorded segments. This abstract is provided to comply with the rules requiring an abstract, and is intended to allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

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

Abstract: A position-measuring device is for measuring the position of two objects that are movable relative to one another. The device includes a measuring graduation, which is connected to one of the two objects, as well as at least one scanning system for scanning the measuring graduation, which is connected to the other of the two objects. The scanning system is arranged to permit a simultaneous determination of the position values along at least one lateral and along one vertical shift direction of the objects.

Abstract: A label-free interferometric biosensor is disclosed which is based on the self-mixing optical interferometer. Inside the biosensor, an incoming beam is divided into two beam portions which pass through a channel and bio materials, respectively. Interference of the portions is realized by the self-mixing effect and used to detect existence of an analyte, such as DNA or protein molecules. The label-free biosensor is compact and can be made on a chip using the semiconductor technology. It is also convenient to use due to moderate alignment requirement. Furthermore, an array of the interferometers fabricated on a chip enables high-throughput and highly parallel measurements.

Abstract: A phase diversity wavefront sensor includes an optical system including at least one optical element for receiving a light beam; a diffractive optical element having a diffractive pattern defining a filter function, the diffractive optical element being arranged to produce, in conjunction with the optical system, images from the light beam associated with at least two diffraction orders; and a detector for detecting the images and outputting image data corresponding to the detected images. In one embodiment, the optical system, diffractive optical element, and detector are arranged to provide telecentric, pupil plane images of the light beam. A processor receives the image data from the detector, and executes a Gerchberg-Saxton phase retrieval algorithm to measure the wavefront of the light beam.

Abstract: An apparatus including: an interferometric objective comprising a beam splitter surface configured to separate input light into test light and reference light, and a reference surface configured to receive the reference light and direct it back to the beam splitter surface, which is configured to recombine the reference light with test light reflected from a test surface, the interferometric objective further comprising one or more optical elements positioned in the path of the input light and having positive or negative optical power, wherein the reference surface is curved and defines a window to pass the input light towards the beam splitter surface.

Abstract: The invention can provide apparatus and methods for processing wafers using Noise-Reduction (N-R) metrology models that can be used in Double-Patterning (D-P) processing sequences, Double-Exposure (D-E) processing sequences, or other processing sequences.

Abstract: Disclosed is a low-cost high-resolution compact accelerometer which utilizes multiple self-mixing optical interferometers. The device is also a micro-opto-electro-mechanical systems (MOEMS) sensor. The interferometers are used to detect acceleration as well as monitor the wavelength, temperature, and refractive index and perform differential measurements. In addition, photodetectors are employed to monitor the input optical power.

Abstract: A measurement method and apparatus rely upon the coherent optical interference between a reference beam and a diffractionless sensing beam having an optical path length that has been disturbed. The interference pattern can be analyzed to determine a measurement parameter of the disturbance. The diffractionless beam is particularly a Bessel beam. Exemplary optical interferometer types including Mach-Zehnder, Michelson, Sagnac and Fabry-Perot include a Bessel beam generator to generate a diffractionless beam as the sensing optical beam and in some aspects the reference optical beam of the interferometer. The sensing optical beam propagates along a sensing optical beam path in free-space. The reference optical beam path may be a free-space medium or a material medium such as an optical fiber. The sensing optical beam path is subject to a disturbance manifested by the optical interference pattern between the sensing optical beam and the reference optical beam.

Abstract: A light wavefront measuring apparatus (2, 2a, 42) includes a separating element (7a, 47a) for separating a flux of light which exits from an optical head (1, 31) into a first beam and a second beam, a first interference fringe display section (21, 21a) for displaying interference fringes formed from the first beam, a Dove prism (13, 53) for rotating a wavefront of the second beam around its optical axis (AX2), and a second interference fringe display section (22, 22a) for displaying interference fringes formed from the second beam which passed through it. In adjustment of the light source device, position of a collimator (5) in the optical head (1, 31) is adjusted in optical axis direction so as to approximate the interference fringe patterns displayed in the interference fringe display sections (21, 22, 21a, 22a) each other.

Abstract: In a wavefront sensor, an optical wavefront to be measured that has entered an entrance pupil P is split into a first optical path L1 and a second optical path L2 by a semi-transparent mirror 3. A wavefront W1 traveling in the first optical path L1 is transmitted through a first optical path difference compensation member 7, and a wavefront W2 traveling in the second optical path L2 is transmitted through a second optical path difference compensation member 8. The wavefronts W1 and W2 are mixed together again by a semi-transparent mirror 6 in a state where the wavefronts are displaced from each other by a shearing quantity S to form an interference fringe on an interference measurement plane M. The intensity distribution of the interference fringe is measured by a photodetector 9, and a configuration of the optical wavefront to be measured is measured by a wavefront measurement portion 10.

Abstract: An optical image measurement device comprises: a light source configured to output a light having low temporal coherence and low spatial coherence; an optical system configured to split the light into a signal light and a reference light and superimpose the signal light having passed through a measured object and the reference light, thereby generating an interference light; a light receiver configured to receive the interference light and output an electric signal; and a forming part configured to form an image of the measured object based on the electric signal, wherein: the light receiver has a light receiving face on which a plurality of light receiving elements are arranged 2-dimensionally; and the optical system projects the interference light onto the light receiving face so that a size of the spatial coherent region of the interference light becomes equal to or larger than a size of the light receiving element.

Abstract: A method and apparatus for measuring the chromatic response of lithographic projection imaging systems is described. An apparatus for determining the lens aberrations for a lithographic projection lens is provided. A substrate coated with a suitable recording media is provided. A series of lithographic exposures are performed using an exposure source with variable spectral settings. The exposures are measured, and the measurements are used to determine a chromatic response of the projection imaging system.

Abstract: A microscope includes a source of electromagnetic radiation, having a wavelength, ?1 and dividing optical elements configured for dividing the radiation from the source into multiple excitation beams. The microscope also includes a detector and directing optical elements, which are configured for directing each excitation beam in unique directions, such that the beams intersect in an excitation region within a sample to create a two-dimensional or three-dimensional interference pattern of multiple excitation maxima within the sample. The detector has individual detector elements, where the detector elements are configured for detecting light resulting from an interaction of an individual excitation maximum and the sample.

Abstract: Apparatus and techniques for using an optical shearing interferometry to obtain full field mapping of in-plane and out-of-plane displacement field gradients of a sample surface of a sample.

Abstract: A method of determining a deviation of an actual shape from a desired shape of an optical surface (12; 103) includes: providing an incoming electromagnetic measuring wave (20; 113), providing two diffractive structures (47, 49; 145, 146, 141, 143) which are respectively designed to reshape the wavefront of an arriving wave, calibrating one of the two diffractive structures (47, 49; 145, 146, 141, 143) by radiating the incoming measuring wave (20; 113) onto the at least one diffractive structure to be calibrated (47, 49; 145, 146, 141, 143) and determining a calibration deviation of the actual wavefront from a desired wavefront of the measuring wave (20; 113) after interaction of the latter with the at least one diffractive structure to be calibrated (47, 49; 145, 146, 141, 143), positioning the two diffractive structures (47; 49; 145, 146, 141, 143) in the optical path of the incoming measuring wave (20; 113) such that individual rays of the measuring wave radiate through both diffractive structures (47; 49;

Abstract: The present invention discloses an interferometer device and method. In embodiments, the device comprises an electromagnetic radiation source emitting radiation having a first mean wavelength ?LE; a phase grating having a first aspect ratio; an absorption grating having a second aspect ratio; and a detector. The electromagnetic radiation source, the phase grating, the absorption grating and the detector are radiatively coupled with each other. The absorption grating is positioned between the detector and the phase grating; the electromagnetic radiation source is positioned in front of the source grating; and wherein the phase grating is designed such to cause a phase shift that is smaller than ? on the emitted radiation. Additional and alternative embodiments are specified and claimed.

Abstract: A device for the optical measurement of an optical system which, in a useful operating mode, receives useful radiation on a useful radiation entrance side and emits it on a useful radiation exit side. The device includes a measurement radiation source, by which at least one exit-side element, which emits measurement radiation to the optical system, can be positioned on the useful radiation exit side of the optical system, and a detector, by which at least one entrance-side element, which receives measurement radiation coming from the optical system, can be positioned on the useful radiation entrance side of the optical system. The measurement radiation source includes a source-side measurement structure mask for positioning on the useful radiation exit side and/or the detector includes a detector-side measurement structure mask for positioning on the useful radiation entrance side.

Abstract: A method of imaging critical dimensions by measuring the zeroeth order of diffracted light. The method involves providing a target, directing light onto the target so as to cause the target to diffract the light. The zeroeth order of the diffracted light is collected and analyzed to determine structural features of the target. The target can be an article of manufacture, such as a semiconductor device, or a separate target that is provided or fabricated on an article of manufacture. One of at least the wavelength and the angle at which the light is directed onto the target can be scanned. The target can fill all or only a portion of the field of view.

Abstract: To reduce a bad influence on a tracking control signal and a data signal by reflected light from an adjacent layer on a multi-layer disc as stray light, the following device is made in the invention. Reflected light from the multi-layer optical disc including stray light from another layer is once converged by a reflected light condenser lens and is reflected on a reflector. A grating which prevents zero-order light from being generated by setting groove depth to ?/4 and which is set to pitch to prevent positive and negative first- or higher-order diffracted lights from returning to the reflected light condenser lens is arranged between the lens and the reflector including an optical axis with the grating apart from the reflector. Hereby, as reflected light from another layer is cut off though reflected light from a corresponding layer is transmitted to a detector, a detected control signal and a detected data signal are not influenced by reflected light from another layer.