Abstract: A spectrometer includes a transparent substrate including a first surface and a second surface that face each other and are substantially parallel to each other; a slit provided on the first surface and through which light is incident onto the transparent substrate; a spectrum optical system including metasurface including a plurality of nanostructures that are two-dimensionally arranged and satisfy a sub-wavelength scattering condition, wherein the metasurface includes a focusing metasurface which includes first nanostructures of the plurality of nanostructures, and is configured to reflect, disperse, and focus the light incident thereon through the slit, at different angles based on respective wavelengths; and a sensor configured to receive the light from the focusing metasurface. When L is a total length of an optical path from the slit to the sensor and D is a thickness of the transparent substrate, L and D satisfy the following inequality: L/D>3.

Abstract: Heights on a surface of a photomask are measured using broadband light interferometry. The heights include heights of patterned areas of the photomask. A focal map is produced from the measured heights on the surface of the photomask. To produce the focal map, the measured heights of the patterned areas are adjusted based on fill factors for the patterned areas. The photomask is inspected for defects, using the focal map.

Abstract: Reference and test waves are directed in a common path mode in a fiber tip diffraction interferometer. A first fiber can be used to generate the reference wave and a second fiber can be used to generate the test wave. Each fiber can include a single mode fiber tip that defines a wedge at an end without a coating on end surface or a tapered fiber tip. The fiber tip diffraction interferometer can include an aplanatic pupil imaging lens or system disposed to receive both the test wave and the reference wave and a sensor configured to receive both the test wave and the reference wave.

Abstract: Disclosed is a system for inspecting a structure without physically contacting the structure. The system includes a remotely controlled device that includes a sonar/ultrasound transceiver, a camera and a mapping module for generating geotags corresponding to the structure. The remotely controlled device optionally includes an infrared camera and a lidar. As the remotely controlled device moves along or around the perimeter of the structure, the system collects acoustic, lidar, infrared and photogrammetry data to create a virtual model of the structure. Geotagged acoustic, infrared and lidar data identifying faults in the structure is overlaid on the virtual model of the structure.

Abstract: A measuring apparatus comprising a tunable laser diode for generating a mono mode measurement radiation, said laser diode being designed as a laser beam source in such a way that an emission wavelength of the measurement radiation is variable within a wavelength range by means of the variation of a tuning parameter, comprising an absorption medium defining absorption lines within the wavelength range, comprising a memory having a line atlas for the absorption medium, comprising a detector for determining an absorptivity and comprising a control and evaluation unit for regulating the emission wavelength by means of the at least one tuning parameter in a manner dependent on the absorptivity determined in such a way that the emission wavelength remains stable.

Abstract: Disclosed is a method for controlling surface errors of a sample in a homogeneity measurement of infrared optical materials. In this invention, a calculation relationship among the surface errors, measurement principles and precision requirements is established. The wavefront distortion caused by the surface errors of the sample measured in infrared wavebands is converted to the surface errors of the sample which is processed and inspected under the visible light. Through establishing related algorithms and formulas for numerical calculations, a numerical table for controlling the surface errors of the sample is created to ensure the precision of the homogeneity measurement for the infrared optical material under short, middle and long wavebands. A case table for controlling the surface errors of the sample is also provided to ensure the precision of the homogeneity measurement for the specific infrared optical materials under short, middle and long wavebands.

Abstract: The ROC value of a test surface is measured with a single spectrally-controlled interferometric measurement using a reference source of known ROC. The test surface is placed at the confocal position of the reference surface and the light source is modulated so as to produce localized interference fringes at the location of the test surface. The interference fringes are then processed with conventional interferometric analysis tools to establish the exact position of the test surface in relation to the reference surface, thereby determining the distance between the test surface and the reference surface. The radius of curvature of the test surface is obtained simply by subtracting such distance from the known radius of curvature of the reference surface.

Abstract: A polychromator includes a substrate and a functional element having an optical spectral decomposition action. The functional element having an optical spectral decomposition action is configured to spectrally decompose electromagnetic radiation originating from an entry opening, e.g. light which originates from an optional radiation source and is reflected at a sample, so that a spectrally decomposed spectrum is obtained, and to image the spectrally decomposed spectrum onto a spatial area of the substrate. The substrate includes at least two transparent zones at different positions within the spatial area, so that two different spectral components of the spectrums are detectable at the two transparent zones.

Abstract: The imaging quality of an optical imaging system is interferometrically measured. A wavefront measurement has a first imaging scale ?1 in a first direction and a second imaging scale ?2 in a second, perpendicular direction. The second imaging scale differs from the first imaging scale by a scale ratio (?1/?2)?1 (anamorphic imaging system). A first measurement structure (MS1) on a first structure carrier arranged on the object side of the imaging system has a two-dimensional mask structure suitable for shaping the coherence of measurement radiation. A second measurement structure (MS2) on a second structure carrier arranged on the image side of the imaging system has a diffraction grating. The first and second measurement structures are mutually adapted, taking account of the scale ratio so that an interference pattern arises upon imaging the first measurement structure onto the second measurement structure using the anamorphic imaging system.

Abstract: A method and an apparatus for detecting a concave cylinder and a cylindrical diverging lens are disclosed. In particular, a method for non-contact interference detection of a cylindrical shape is disclosed. A cylindrical converging lens and a cylindrical diverging lens are combined with a to-be-tested concave cylinder respectively. Wavefront error data of the combination of the cylindrical diverging lens and the to-be-tested concave cylinder and wavefront error data of the combination of the cylindrical converging lens and the to-be-tested concave cylinder are obtained through interference measurement respectively. Wavefront error data of a combination of the cylindrical diverging lens and the cylindrical converging lens is then obtained through interference measurement. Shape error data of the to-be-tested concave cylinder, the cylindrical diverging lens, and the cylindrical converging lens is obtained respectively by using a difference algorithm and a wavefront recovery algorithm.

Abstract: A method and an apparatus for detecting a cylinder and a cylindrical converging lens are disclosed. In particular, a method for non-contact interference detection of a cylindrical shape is disclosed. Two converging lenses which modulate parallel light into cylindrical waves are combined with a to-be-tested cylinder respectively. Wavefront error data of the combination of the converging lens and the to-be-tested cylinder and wavefront error data of the combination of the two cylindrical converging lenses are obtained. Shape error data of the to-be-tested cylinder, the two cylindrical converging lenses is obtained respectively by using a difference algorithm and a wavefront recovery algorithm. In the technical solution, a detection light path is simple, and shape detection of a cylinder with relatively high precision can be implemented without using a high-precision detection tool calibrated in advance. The technical solution is particularly suitable for cylinder processing in the field of optical processing.

Abstract: Disclosed is a system for inspecting a structure without physically contacting the structure. The system includes a remotely controlled device that includes a sonar/ultrasound transceiver, a camera and a mapping module for generating geotags corresponding to the structure. The remotely controlled device optionally includes an infrared camera and a lidar. As the remotely controlled device moves along or around the perimeter of the structure, the system collects acoustic, lidar, infrared and photogrammetry data to create a virtual model of the structure. Geotagged acoustic, infrared and lidar data identifying faults in the structure is overlaid on the virtual model of the structure.

Abstract: A LiDAR sensor can include a laser, a directional sensor, a window, an electromagnetic pulse receiving sensor, and a processor. The laser can be configured to emit a narrow electromagnetic pulse. Further, the directional sensor can be configured to measure the direction of the narrow electromagnetic pulse emitted by the laser. The narrow emitted electromagnetic pulse can pass through the window. The pulse can then be reflected by at least the window and an object external from the LiDAR sensor, creating at least two reflected pulses. The electromagnetic pulse receiving sensor can be configured to measure the two reflected pulses resulting from the narrow pulse emitted by the laser. The processor can be configured to receive information from the sensors, indicating a position of the object relative to the LiDAR sensor. Further, the processor can be configured to measure the intensity of the pulse being reflected by the window.

Abstract: There is provided an inspection apparatus, including: an illuminator configured to irradiate a pattern, a detector configured to detect a reflected light from the pattern, and a calculator configured to compare a first change and a second change to calculate a deviation between the first and second changes. The first change which is a change, of a detection result of a pattern formed by a plurality of first exposure conditions, with respect to the first exposure conditions. The second change which is a change, of a detection result of a reflected light, from a pattern, generated by irradiating the pattern with the illumination light. The pattern is formed by a plurality of second exposure conditions each having a predetermined interval in a range which has at least one part overlapping with a range of the first exposure conditions, with respect to the second exposure conditions.

Abstract: A measurement arrangement (10) and an associated method for interferometrically determining the surface shape (12) of a test object (14) includes a light source (16) providing an input wave (18) and a diffractive optical element (24). The diffractive optical element is configured to produce in each case by way of diffraction from the input wave a test wave (26), which is directed at the test object (14) and has a wavefront that is adapted at least partially to a desired shape of the optical surface, and a reference wave (28). The measurement arrangement furthermore includes a reflective optical element (30) that back-reflects the reference wave (28) and a capture device (36) that captures an interferogram produced by superposing the test wave after interaction with the test object and the back-reflected reference wave (28), in each case after a further diffraction at the diffractive optical element in a capture plane (48).

Abstract: A mobile or portable device comprises an illuminating arrangement comprising a light source, and an amplitude splitting interferometer configured to form an interferogram of light emitted by the light source. The illuminating arrangement is configured to illuminate a target region lying at a distance of at least 10 cm from the device by the interferogram, thereby projecting a structured light pattern onto the target region. The device further comprises an image sensor configured to capture at least one digital image frame of the target region illuminated by the interferogram, and a processing unit configured to obtain image data of the at least one digital image frame, and determine depth of at least one object location in the target region relative to a reference location on the basis of the obtained image data.

Abstract: A spectrometer includes a light detection element provided with a light passing part, a first light detection part, and a second light detection part, a support fixed to the light detection element such that a space is formed, a first reflection part provided in the support and configured to reflect light passing through the light passing part in the space, a second reflection part provided in the light detection element and configured to reflect the light reflected by the first reflection part in the space, and a dispersive part provided in the support and configured to disperse and reflect the light reflected by the second reflection part to the first light detection part in the space. A plurality of second light detection parts is disposed in a region surrounding the second reflection part.

Abstract: An apparatus for measuring a curvature of a thin film includes a light emitting module, a first optical module, a second optical module, a third optical module, and an image analysis module. The light emitting module emits a single laser to be used as an incident light. The incident light is transmitted through a first optical path provided by the first optical module, then the incident light is guided by the second optical module to be incident to the thin film through a second optical path. A reflected light reflected by the thin film is transmitted through the second optical path, then guided by the third optical module to be transmitted along a third optical path. The image analysis module determines the curvature of the thin film according to the characteristic of the reflected light.

Abstract: An interferometer includes a short-coherence source and an internal path-matching assembly contained within its housing. Because path matching occurs within the housing of the interferometer, it is removed from external environmental factors that affect measurements. Therefore, a single cateye measurement of an exemplary surface can be performed in advance and stored as a calibration for subsequent radius-of-curvature measurements. In one embodiment, a path-matching stage is incorporated into a dynamic interferometer where orthogonally polarized test and reference beams are fed to a dynamic imaging system. In another embodiment, orthogonal linearly polarized test and reference beams are injected into a remote dynamic interferometer by means of one single-mode polarization-maintaining optical fiber.

Abstract: A method of metrology target design is described. The method includes determining a sensitivity of a parameter for a metrology target design to an optical aberration, determining the parameter for a product design exposed using an optical system of a lithographic apparatus, and determining an impact on the parameter of the metrology target design based on the parameter for the product design and the product of the sensitivity and one or more of the respective aberrations of the optical system.

Abstract: A collimating lens includes at least two lens groups, each having an aspherical surface. The collimating lens also includes a flat diffraction lens disposed nearest to an image plane.

Abstract: A device for emitting electromagnetic radiation includes at least one optical semiconductor element configured to generate electromagnetic radiation, at least one photodiode, and at least one beam splitter. The beam splitter is arranged relative to the optical semiconductor element and the photodiode in such a way that one portion of the electromagnetic radiation generated by the optical semiconductor element passes through the beam splitter and a further portion of the electromagnetic radiation generated by the optical semiconductor element is reflected by the beam splitter and is directed onto the photodiode.

Abstract: A system for generating extreme ultraviolet light may include a chamber, a target supply device configured to supply a target material into the chamber, a laser apparatus configured to output a laser beam to irradiate the target material, a wavefront adjuster configured to adjust a wavefront of the laser beam, an imaging optical system configured to focus the laser beam reflected by the target material, an image detector configured to capture an image of the laser beam focused by the imaging optical system, and a controller configured to control the wavefront adjuster based on the captured image.

Abstract: A method and an apparatus that may include optics that is arranged to illuminate a surface of a sample with radiation and to collect reflected radiation from the surface of the sample; wherein the optics includes a pupil that has multiple pupil segments that correspond to different angular regions of collection or illumination; and a detection module arranged to receive the reflected radiation and generate, for each pupil segment, pupil segment detection signals.

Abstract: An extreme ultraviolet (EUV) light source is provided. The EUV light source comprises a spray nozzle array having a plurality of spray nozzles configured to spray a plurality of rows of droplets to an irradiating position. The EUV light source also includes a laser source having a first reflective mirror and a second reflective mirror configured to generate a first laser beam and a second laser beam, and to cause the first laser beam and the second laser beam to sequentially bombard the plurality of droplets arriving at the irritating position to generate EUV light with increased output power. Further, the EUV light source includes a light focusing device a light focusing device comprising a first partial focusing mirror and a second partial focusing mirror configured to perform a rotating scanning to collect EUV light and focus the collected EUV light at a central focusing point.

Abstract: A temperature insensitive (athermal) channeled spectropolarimeter (CSP) is described. The athermal CSP includes a crystal retarder formed of a biaxial crystal. The crystal retarder has three crystal axes, wherein each axis has its own distinct index of refraction. The axes are oriented in a particular manner, causing an amplitude modulating carrier frequency induced by the crystal retarder to be thermally invariant. Accordingly, a calibration beam technique can be used over a relatively wide range of ambient temperatures, with a common calibration data set.

Abstract: The observation device 1 is to observe the surface or the inside of an observation object 9, that has light sources 11 and 12, lenses 21 to 25, an aperture 31, an optical multiplexer 41, an optical demultiplexer 42, a half mirror 43, an image pickup unit 51, an analyzing unit 52, a display unit 53, a light receiving unit 61, a displacement detecting unit 62, a piezoelectric actuator 71, a drive unit 72, a mirror 73, a stage 81, a drive unit 82, and a control unit 90. The analyzing unit 52 determines a complex amplitude of an interference light figure taken as an image by the image pickup unit 51 with a phase shift technique after an optical path difference is set to each target value in sequence, and determines an amount of change per certain time of a phase component of a reflected light generated on the surface or the inside of the observation object 9 on the basis of an absolute value of an amount of change per certain time of the determined complex amplitude and an absolute value of the complex amplitude.

Abstract: A measurement apparatus includes: a vibration detection surface which has a set relative position with respect to a test surface, and is irradiated with a part of the measurement light; an image sensor configured to sense, together with a first interference fringe generated by interference between reference light from a reference surface and measurement light from the test surface, a second interference fringe generated by interference between light from the vibration detection surface and the reference light; and a processor configured to obtain a relative vibration between the reference surface and the test surface by using data of the sensed second interference fringe, and obtain the shape of the test surface by using the obtained relative vibration and data of the sensed first interference fringe.

Abstract: Methods and apparatus for pixel multiplication in optical imaging systems. In one example, an expanded optical point spread function, referred to as a code spread function, is used to phase modulate an incident electromagnetic wavefront, and digital processing, including correlation techniques, are used to filter and process the modulated wavefront to recover sub-pixel information from an image produced by the wavefront on a pixilated detector array.

Abstract: A reference image to serve as a reference for a non-defective determination is previously stored in association with identification information for identifying an inspection object. An image of the inspection object is displayed side by side with the reference image of corresponding identification information. A drawn position of the reference image and a drawn position of the acquired image are aligned, adjustment is made so as to make brightness of the reference image coincide with brightness of the acquired image, and adjustment is made so as to make a focus on the reference image coincide with a focus on the acquired image. Adjustment is made so as to make a focus of the reference image coincide with a focus of the acquired image.

Abstract: The method for measuring profile of an aspheric surface projects an illumination light onto the aspheric surface and introduces a reflected light reflected by the aspheric surface to a sensor through an optical system. The method provides, to a wavefront of the illumination light, a curvature bringing an absolute value of an angle of the reflected light to a smaller value than a maximum value of absolute values of angles of optical system side peripheral rays, locates an exit pupil such that the absolute value of the reflected light angle is smaller than the maximum value, provides, to a sensor conjugate surface, a curvature and a position causing rays of the reflected light not to intersect on the sensor conjugate surface. The sensor conjugate surface, the wavefront of the illumination light and the aspheric surface have a same one of convex and concave surfaces toward a same direction.

Abstract: Provided herein is a TSV measuring interferometer that uses a variable field stop that adjusts such that a light is focused at an inlet and at a bottom surface of a TSV when measuring a diameter and depth of the TSV, thereby reducing a measurement time and result data, the interferometer also using a telecentric lens that adjusts the light injected into the TSV to be a straight line, so as to obtain a sufficient amount of light reaching the bottom surface to improve the accuracy of measurement even in a TSV having a large aspect ratio.

Abstract: Apparatus and methods for performing wavefront-based and profile-based measurements of an aspheric surface are disclosed. The apparatus includes an interferometric wavefront measurement system that collects wavefront-based measurement data of the aspheric surface. The apparatus also includes a profile measurement system that performs at least one non-contact profile-based measurement of the aspheric surface to collect profile-based measurement data of the aspheric surface. The measurements are performed without removing the aspheric element from a rotatable base. The two measurements are then used to form a combined measurement of the aspheric surface.

Abstract: An Integrated Laser Field Conjugation System (ILFCS) for end-to-end compensation of high-energy laser for propagation through turbulence with non-cooperative target. ILFCS using interferometric slaving technique and stand-alone adaptive optical systems to effect pre-compensation of amplitude and phase aberrations in turbulent medium, providing pre-compensation for aberrations in a laser amplifier. Performing compensation functions in low-power beam paths, increasing capability, reducing cost, reducing size compensation components for phase correction devices. Pre-compensating low-power master oscillator beam for aberrations in both high-power amplifier and turbulent propagation path-to-target with configuration enabling wavefront sensing of aberrations. Can be configured to perform phase compensation, or compensation of phase/amplitude aberrations. Capability to compensate aberrations in master oscillator beam.

Abstract: Apparatus and methods for detecting optical profile are disclosed herein. In one embodiment, an apparatus includes a laser, a beam splitter, a collimation optical unit, first and second holders respectively holding a first test flat mirror and a second test flat mirror, a phase shifter connected with the first holder, and an angular measurement unit for measuring an angular error of the first test flat mirror and the second test flat mirror on the two holders. The first test flat mirror has a first test flat and the second test flat mirror has a second test flat. The apparatus further includes a planar imaging unit for generating the interfered test light having a direction generally along an x-axis direction of the first test flat and an x-axis direction of the second test flat and a convergence optical unit for projecting the interfered test light onto a detector.

Abstract: The present invention is directed to more accurately acquiring shape data than conventional techniques. After an imaging unit images an interference fringe, a calculation unit acquires the captured image from the imaging unit. The calculation unit extracts a ring zone region where the interference fringe is sparse in the captured image from each captured image, and calculates a phase distribution of the interference fringe in each ring zone region. The calculation unit acquires a deviation component having an orientation and an amount both unchangeable along a circumferential direction of a circle centered at the optical axis of the subject light by analyzing the interference fringe contained in each acquired captured image. Further, the calculation unit calculates positions of characteristic points of a calibrator, and calculates a distortion component. Then, the calculation unit calculates the shape data corrected based on the deviation component and the distortion component.

Abstract: A circular common-path point diffraction interference wavefront sensor includes an optical matching system, a beam-splitter, a first reflection mirror, a second reflection mirror, a first Fourier lens, a second Fourier lens, a charge-coupled device (CCD) detector, a computer system, and a two-pinhole mask having a reference pinhole and a testing window and placed at a confocal plane of the first Fourier lens and the second Fourier lens. A testing beam is divided into two beams through the beam-splitter. One beam makes the pinhole diffraction by the reference pinhole, thereby producing the approximately ideal plane wave as the reference wave. Another beam passes through the testing window almost without any attenuation as the signal wave. The spatially linear carrier frequency is introduced by adjusting the tilt angle of the beam-splitter. The present invention is adapted for all kinds of dynamic and static detection field of wavefront phase.

Abstract: A method of determining a shape of an optical test surface (14) includes: with adaptation optics (20), adapting a wavefront of a measuring beam (30) to a desired shape of the optical test surface (14), interferometrically measuring the shape of the optical test surface (14) with the adapted measuring beam, irradiating the adapted measuring beam at different angles of incidence onto the optical test surface and respectively measuring the wavefront of the measuring beam after the interaction of the measuring beam with the optical test surface (14), establishing the effect of the adaptation optics (20) upon the interferometric measurement result from the wavefronts measured for the individual angles of incidence, and determining the shape of the optical test surface (14) by removing the established effect of the adaptation optics (20) from the interferometric measurement result.

Abstract: Provided is a measurement method or apparatus that can reduce the time for measuring the shape of an entire test surface. Each of a plurality of measurement ranges is set so that one measurement range overlaps a portion of at least another measurement range to form an overlap region, each measurement range being a portion of the test surface. Then, the shape of the test surface is measured at a first resolution in a first measurement range among the plurality of measurement ranges, and is measured at a second resolution in a second measurement range. Pieces of data of the shapes of the test surface in the plurality of measurement ranges are stitched together using the resulting measurement data to calculate the shape of the test surface.

Abstract: The time delay (and therefore the OPD) between object and reference beams in an interferometer is manipulated by changing the spectral properties of the source. The spectral distribution is tuned to produce a modulation peak at a value of OPD equal to the optical distance between the object and reference arms of a Fizeau interferometer, thereby enabling the use of its common-axis configuration to carry out white-light measurements free of coherence noise. Unwanted interferences from other reflections in the optical path are also removed by illuminating the object with appropriate spectral characteristics. OPD scanning is implemented without mechanical means by altering the source spectrum over time so as to shift the peak location by a predetermined scanning step between acquisition frames. The invention and its advantages are applicable to optical coherence tomography as well as conventional white light interferometry.

Abstract: Measuring a shape of an optical surface (14) of a test object (12) includes: providing an interferometric measuring device (16) generating a measurement wave (18); arranging the measuring device (16) and the test object (12) consecutively at different measurement positions relative to each other, such that different regions (20) of the optical surface (14) are illuminated by the measurement wave (18); measuring positional coordinates of the measuring device (16) at the different measurement positions in relation to the test object (12); obtaining surface region measurements by interferometrically measuring the wavefront of the measurement wave (18) after interaction with the respective region (20) of the optical surface (14) using the measuring device (16) in each of the measurement positions; and determining the actual shape of the optical surface (14) by computationally combining the surface region measurements based on the measured positional coordinates of the measuring device (16) at each of the measurem

Abstract: A method of testing figure quality of a convex mirror in which an optical quality substrate material is used. Three separate interferometric null tests are carried out to produce three independent sets of optical path difference (OPD) data. Null lenses, or nulling computer generated holograms (CGHs), are designed and used as needed in each test setup so that spherical aberration is corrected. From the three sets of OPD data, surface figure errors on the rear and front surfaces of the test optic are calculated as well as the OPD error introduced by refractive index inhomogeneity in the substrate material. The rear surface is then corrected, generally using a computer-controlled polishing machine, to reduce rear surface errors to a manageably small level. The front convex surface of the test optic is then corrected to reduce surface figure error to within some specified amount.

Abstract: A low coherent light from a white light source is emitted to a sample surface. A detour distance in a detour section is adjusted such that an optical path difference between a reference light and a sample light is equal to or shorter than a coherence length of interference light. The interference light is incident on an image sensor only when an inclination angle of a diffraction grating plate and a wavelength of the interference light satisfy a predetermined condition. Thus, an interference fringe image is formed. Based on each of the interference fringe images taken on a wavelength-by-wavelength basis of the interference light and an optical distance between a reference surface and the sample surface along an optical path of a measuring light at the time of taking the interference fringe image, a shape of the sample surface is measured.

Abstract: A Fizeau interferometer incorporates an off-axis paraboloidal reflector that forms virtual images of reference and test surfaces and a camera lens that converts the virtual images into real images on a camera detector surface. The camera detector surface is arranged together with the camera lens to accommodate tilting of the virtual images by the off-axis paraboloidal reflector.

Abstract: The present invention provides a measurement apparatus which measures a surface shape of a measurement target surface, the apparatus including an optical system configured to split light from a light source into measurement light and reference light, guide the measurement light onto the measurement target surface, and guide the reference light onto a reference surface, a detection unit configured to detect an intensity of the measurement light reflected by the measurement target surface, an intensity of the reference light reflected by the reference surface, and an interference pattern formed between the measurement light reflected by the measurement target surface and the reference light reflected by the reference surface, and a processing unit configured to obtain a surface shape of the measurement target surface based on an interference signal of the interference pattern detected by the detection unit.

Abstract: A surface profile measuring apparatus includes a first image pickup device that obtains an interference pattern, an optical system that guides a measuring beam and a reference beam to the first image pickup device, a second image pickup device with which a distribution of light quantity of a beam from a light source traveling thereto avoiding the optical system is measured, and an arithmetic unit that calculates a profile of a target surface from the interference pattern. A distribution of light quantity of a beam from the light source transmitted through the optical system is measured with the first image pickup device. The profile of the target surface calculated by the arithmetic unit is corrected on the basis of the distributions of light quantity measured with the first and second image pickup devices.

Abstract: Deformations of a surface of a test object can be measured by attaching mirrors to a surface of a test object, each mirror having a reflective surface with a dimension and a radius of curvature smaller than those of the surface of the test object. Light is directed towards the mirrors and a reference surface, and interference patterns are generated using light reflected from the mirrors and the reference surface. Changes in the surface of the test object are determined based on the interference patterns.

Abstract: A miniaturized Holographic Fourier transform imaging spectrometer HFTIS, made from simple all-reflective components and with no moving parts, is provided. This HFTIS includes an all-reflective two beam interferometer, which provides two interfering beams; a two-dimensional detector array to detect the interference pattern created by the beams; a computing machine for correcting the distortions in the pattern and calculating the spectrum from the corrected interferogram. The same principle can be used to build spot spectrometers, line-scan imaging spectrometers (also called array spectrometers or line-scan hyperspectral cameras) as well as two-dimensional instantaneous imaging spectrometers (also called staring hyperspectral cameras). In all variants of HFTIS that can be built using this invention, the wave-signal collecting element can also be built of all-reflective components.

Abstract: A method of testing a convex mirror surface figure in which an optical quality substrate material is used having a convex front surface and a rear surface polished to a precise optical figure to create a lens. The lens is then tested by a standard interferometric or wavefront lens-testing method and the convex surface coated once a desired curvature is obtained. Null testing may be attained by passing a collimated interferometer beam through a focusing lens shaped to counter the predicted spherical aberration introduced by a perfect convex mirror/lens.

Abstract: A method detects a topology of a reflective surface. The method includes providing an optical fiber positioned such that light emitted from the optical fiber is reflected by at least a portion of the reflective surface. The optical fiber and the portion of the reflective surface form an optical resonator having an optical resonance with a resonance lineshape. The method further includes emitting light from the optical fiber while the optical fiber is at a plurality of positions along the reflective surface. The light emitted from the optical fiber irradiates a corresponding plurality of portions of the reflective surface. The method further includes measuring a change of the resonance lineshape due to the irradiation of the plurality of portions of the reflective surface.