295results about "Interferometers" patented technology

Disclosed in the present invention are a dual electro-optic frequency comb-based laser tracking interferometric spatial coordinate measurement system and method. Multiple target mirrors are identified by means of a vision module, to guide a rotating mirror to direct laser light toward each target mirror individually. A laser tracking interferometric ranging module obtains a tracking error of the laser beam deviating from the center of the target mirror to be used for closed-loop tracking control. A light source module outputs single-frequency laser light traceable to a gas absorption peak. By controlling a light source modulation module to enable or disable an electro-optic phase modulation drive signal, dual electro-optic frequency combs or dual-frequency continuous-wave laser light is outputted. In a tracking state, the laser tracking interferometric ranging module respectively uses the two light sources to measure the absolute distance and the relative displacement of a target mirror, and the real-time distance between the target mirror and an original point is computed by means of distance fusion; the elevation angle and the azimuth angle of the target mirror are obtained in real time by means of an azimuth angle and elevation angle measurement module; tracking control and coordinate computation are carried out by means of a tracking control and signal processing module and a computer, and finally three-dimensional spatial coordinates of all the target mirrors are measured.

A device for interface shape of an optical element including at least one low-coherence light source, at least one optical sensor, an interferometric device illuminated by the light source and configured for shaping at least one measurement beam and at least two reference beams, directing one measurement beam to the element to pass through the interfaces, and directing the light from at least two interfaces to the sensor or sensors, each sensor globally configured for detecting at least two interference signals resulting respectively from interferences between the measurement beam reflected by one of the at least two interfaces and one of the reference beams; the measurement device also including a positioner for positioning a coherence area at the level of each interface and a digital processor for producing, from the interference signals, an item of information of the shape of each interface according to a field of view.

A laser processing apparatus includes a laser oscillator that oscillates processing laser light to be incident on a processing point on a processing surface of a workpiece, a coupling mirror that deflects or transmits the processing laser light and measurement light to be incident on the processing point toward the processing point, a measurement light deflection unit that changes an incident angle of the measurement light on the coupling mirror, a lens that concentrates the processing laser light and the measurement light on the processing point, a controller that controls the laser oscillator and the measurement light deflection unit, a measurement processor that measures a depth of a keyhole generated at the processing point by the processing laser light by using an optical interference signal based on an interference generated by an optical path difference between the measurement light reflected at the processing point and reference light, and a beam position measurement unit that measures positions of the processing laser light and the measurement light.

Provided are a laser interferometer capable of reducing the frequency of a signal calculated and processed in a demodulation circuit and reducing the cost of the demodulation circuit, and a spectroscopic device provided with the laser interferometer. A laser interferometer is provided with: an optical modulator that adds a modulation signal to laser light using a resonator element; a light receiving element that detects a change in the intensity of the laser light including the sampled signal and the modulated signal, and outputs a laser reception signal; a signal oscillation unit that generates a reference signal of a first frequency with the vibration element as a source vibration; and a demodulation circuit that demodulates the sampled signal from the laser reception signal on the basis of the reference signal, the demodulation circuit comprising: a DC offset removal unit that removes the offset; a first phase regulator that regulates the phase of the reference signal; a first multiplier that multiplies the laser reception signal by a reference signal; a first filter; a second multiplier multiplying the first multiplication signal by a reference signal; a second filter; and a phase calculator that calculates a phase.

The invention relates to the technical field of grating interferometry, in particular to a Littrow grating interferometry device and a use thereof. The device comprises: a two-frequency orthogonal polarization light source, a polarizing beam splitting prism, a reflection assembly, a detector, and a first diffraction grating and a second diffraction grating having identical parameters. The output light of the two-frequency orthogonal polarization light source is split by the polarizing beam splitting prism into horizontally polarizing measuring light which is transmitted and vertically polarizing measuring light which is reflected. The two beams of measuring light undergo diffraction twice between the first diffraction grating and the second diffraction grating, and finally the two beams of measuring light interfere with each other and are incident on the detector. Grating displacement is calculated according to the interference pattern. The invention achieves secondary diffraction under Littrow incidence, and improves the precision of displacement measurement.

An imaging device comprising a detector assembly having sensor elements configured to measure intensity of light / radiation thereby received and generate measurement data / signals indicative thereof, an aperture assembly having at least two partial apertures configured to divide light / radiation received from an object into at least two components having different polarization orientations, a polarizer arrangement located between the detector assembly and the aperture assembly, wherein the polarizer arrangement is configured to affect at least two different polarization orientations to light passing therethrough onto at least two sensor elements of the detector assembly, and a processor unit configured to process the measurement data / signals from the at least two sensor elements, and determine based thereon a distance of the object from the imaging device.

A measuring arrangement (10) for determining the position of a movable component (526) in a system (500) comprises an optical resonator (26) with two resonator mirrors (28, 30) which enclose a resonator cavity (32), a movable measuring mirror (14) assigned to the component, which is arranged within the resonator cavity for deflecting a measuring radiation (18) back and forth between the resonator mirrors and is movable from a home position, and a focusing lens (34). The lens (34) is arranged immovably within the resonator cavity (32) such that the measuring mirror is arranged in a cat's eye position of the lens in the home position.

A line-field optical coherence tomography (OCT) system and method provide enhanced imaging accuracy through k-linearization of interference data. The system includes a swept laser source, a line-field sensor, and a single board computer (SBC) with processing capabilities. The system uses a frequency reference to produce a periodic reference pattern, which is detected by a subset of pixels in the line-field sensor. The SBC determines a resampling curve based on the reference pattern to correct non-linearities in the wavelength tuning of the laser. The resampling curve is applied to k-linearize the interference data, enabling the generation of high resolution transform-limited depth profiles through inverse Fourier transform. Methods are disclosed for recalculating the resampling curve periodically, continuously, or adaptively based on a linearity threshold. The system can further update the laser's tuning function dynamically to ensure consistent performance. These advancements enable precise and efficient OCT imaging for applications such as ophthalmology, angiography, and other diagnostic uses.

An OCT instrument comprising: an optical coupler which generates signal light and reference light from a swept narrowband light source; a detector which samples a time-varying interference signal based on the reference light and signal light returned from a sample; an adjustable optical frequency shifter which: generates a first sideband light by adjusting an optical frequency of the reference light, such that the detector unit samples a first time-varying interference signal resulting from an interference between the sideband light and the returned signal light; and maintains the optical frequency of the reference light such that the detector unit samples a second time-varying interference signal resulting from an interference between the reference light and the returned signal light. The OCT instrument generates a respective axial depth profile of the sample based on each of the sampled first time-varying interference signal and the sampled second time-varying interference signal.

The invention relates to an optical measuring arrangement (100) for detecting a distance between a first component and a second component by measuring the length of at least one measuring path (101), wherein the measuring path (101) is spanned between at least two facets (102, 103) forming a measuring head, which are directly or indirectly connected or connectable to the first component, and a measuring target (104) arranged in the measuring path (101), which is directly or indirectly connected or connectable to the second component and is configured to deflect a measuring beam (105) back and forth in the measuring path (101) between the facets, wherein the second facet (103) is formed as a reflecting facet (103). The center of curvature of one of the facets (102, 103) of the measuring head is located on the measuring target (104) or at most 20% of the distance between the facet (102, 103) and the measuring target (104). The invention further relates to a projection exposure system, a lithography system, an inspection system and a coordinate measuring machine.

The invention relates to an optical measuring arrangement (100) for measuring the distance of a component relative to a reference along at least one measuring axis, comprising a sensor (101) with a sensor head (102) and a measuring target (103) connected or connectable to the component, wherein the sensor head (102) has an input mirror (104) for coupling a measuring beam (106) and an end mirror (105) enclosing a resonator cavity (107) of an optical resonator, and wherein the measuring target (103) is configured to deflect the measuring beam (106) back and forth between the mirrors (104, 105, 108, 109) of the sensor head (102). The sensor head (102) additionally has at least two retroreflectors (108, 109).

A device (14) and a method for measuring wafers (10), comprising an optical coherence tomograph (22) configured to generate a measuring light beam (24) and direct it onto the wafer (10) via an optical system (38), a scanning device (26) configured to deflect the measuring light beam (24) in two spatial directions, a control unit (36) configured to control the scanning device (26) so that the measuring light beam (24) successively scans the surface of the wafer (10) at several measuring points, and an evaluation unit (57) configured to calculate distance values ​​and / or thickness values ​​from interference signals provided by the optical coherence tomograph (22), and a camera (80) configured to capture an image of the surface of the wafer (10), wherein the camera (80) images camera light (83).which has passed through the optical system (38) at least partially from the wafer (10).

The invention relates to an optical measuring arrangement (100) for position and / or distance detection of a component relative to a reference along at least one measuring axis, comprising an optical resonator (101) which has at least one coupling mirror (102) for coupling a measuring beam (103) and an end mirror (104) enclosing a resonator cavity (105). The resonator cavity (105) has a length adjustment range, wherein the measuring beam passes through the resonator cavity (105) more than once. The optical resonator (101) has at least one optical element (108) which is configured to control, at least within the length adjustment range (107) of the resonator cavity (105), the beam radius of the measuring beam (103) at the coupling mirror (102) and / or a Gouy phase of the measuring beam (103) propagating in the resonator cavity (105).The invention further relates to a projection exposure system, a lithography system, an inspection system and a coordinate measuring machine.

An optical device includes: an incident optical system; an analysis optical system; and a length measurement optical system. The incident optical system includes a laser light source, and an incident light dividing element that divides the laser light. The analysis optical system includes a first light dividing element that divides the first divided light and then mixes the light, a first mirror that adds a first modulation signal to the one first divided light by movement and reflection, a second mirror, and a first light receiving element that receives the first divided light including a sample-derived signal and the first modulation signal. The length measurement optical system includes a second light dividing element that divides the second divided light and then mixes the light, an optical feedback unit that feeds back the one second divided light to the second light dividing element, and a second light receiving element that receives the second divided light including a displacement signal generated by the first mirror.

An optical displacement sensor comprises a reflective surface and one or more diffraction gratings which, together with the reflective surface, each define a respective interferometric arrangement. The reflective surface is moveable relative to the diffraction grating(s) or vice versa. Light from a light source propagates via the interferometric arrangement(s) to produce an interference pattern at a respective set of photo detectors. Each interference pattern depends on the separation between the reflective surface and the respective grating. A collimating optical arrangement at least partially collimates the light between the light source and the diffraction grating(s). For the or each interferometric arrangement, when the reflective surface or the diffraction grating is in a zero-displacement position, the optical path length L of the light propagating between the diffraction grating and the reflective surface satisfies the relationship:L=Tz⁢n2,to within 20% ofTz2, where n is an integer; where Tz is the Talbot length, defined by:Tz=λ1-1-λ2p2,where λ is the wavelength of the light, and where p is the grating period of the respective diffraction grating.

The present invention relates to a measuring apparatus (10) for measuring the interference shape of the surface (12) of a test object (14-1; 14-2), the measuring apparatus comprising: a diffractive optical element (26-1; 26-2) for generating a test wave (28) from a measurement radiation (18) that has been radiated into the test object, the test wave being configured to radiate onto the surface of the test object; a deflection element (22) upstream of the diffractive optical element in the beam path of the measurement radiation; and a holding device (24, 124) for holding the deflection element, the holding device being configured to change the position of the deflection element (22) by a combination of tilting motion and translational motion.

The invention relates to a method for interferometric surface measurement of a test specimen, a computer-generated hologram (CGH) and an interferometric test arrangement. In a method according to the invention, an interferometric superposition of a test wave directed by a CGH (120, 220, 320, 410, 420, 430, 510) onto the test piece (140, 240, 340, 540) and reflected therefrom is carried out with a reference wave not reflected at the test piece, wherein, based on a further interferometric superposition of light reflected at at least one Littrow structure (122, 222, 322, 412, 422, 432, 512) of the CGH with light reflected at a reference surface, a contribution to the optical effect of the CGH caused by a deformation present at the CGH is determined, and wherein a determination of the fit of the test piece (140, 240, 340, 540) is carried out taking this contribution into account.

A light source projects a light beam. An interferometer includes a splitting unit that splits the light beam. The interferometer generates interference beams with the respective split light beams. Each of the interference beam is generated by interference between a measurement beam radiated toward the measurement target and reflected at the measurement beam and a reference beam passing through an optical path. A light-receiving unit receives the interference beams. A processor calculates a distance to the measurement target by associating at least one detected peak with at least one of the spots in accordance with a mirror surface mode or a rough surface mode. The optical path length difference is made different among the split light beams. In the mirror surface mode, the processor uses a distance calculated based on a peak corresponding to a spot for which the optical path length difference is shortest.

Optical coherence tomograph for examining an eye (3) which features: - a lighting device (4, 5) for providing source radiation, - an illumination and measurement beam path (7) comprising a splitting element (6) for splitting the source radiation into illumination radiation (B) and reference radiation (R), with the illumination radiation (B) illuminating an illumination field in the eye (3) and collecting backscattered illumination radiation in the eye (3) as measurement radiation (M), wherein the illumination and measurement beam path (7) comprises a scanner (13) for adjusting the lateral position of the illumination field in the eye (3) and a front optic (12), - a reference beam path (8) which provides for the reference radiation (R) an optical path length (21) corresponding to an optical path length from the splitting element (6) to the illumination field and back to a superposition point (71), - a detection beam path (14, 15, 17) which receives the measuring radiation (M) from the illumination and measuring beam path (7) and the reference radiation (R) from the reference beam path (8) and superimposes them at the superposition point (71) and directs them onto a detector (19), - the illumination and measuring beam path (7) further exhibits - a beam splitter (11) for separating the measuring radiation (M) collected by the eye (3) from the illumination radiation (B) directed to the eye (3), wherein the beam splitter (11) directs the separated measuring radiation (M) to the detection beam path (14, 15, 17), and - a light splitting element (32, 34) that splits the illumination radiation (B) into spots in order to illuminate the retina (2) with a multi-spot pattern, characterized in that - the lighting device (4, 5) is tunable with respect to the wavelength of the source radiation, - the detector is an area detector (19), - the detection beam path further - an optical element (14) acting only on the measuring radiation (M), which interacts with the front optics (12) and adjusts the numerical aperture with which measuring radiation (M) is collected in the eye (3), and - an aperture (15) which is arranged in front of the area detector (19), in or near an intermediate image plane and which defines the size of an object field from which the measuring radiation (M) reaches the area detector (19), and - wherein the aperture prior to the area detector is designed as a first multi-hole aperture (15) and a first multi-lens array (36) is arranged between this multi-hole aperture and the area detector (19), which focuses the radiation emanating from each hole of the first multi-hole aperture (15, 15a, 15b) onto a pixel area of ​​the area detector (19) which has a spatial resolution of 4 to 100 pixels in one direction, preferably as a 2D pixel area with 5 to 50 pixels or 5 to 40 pixels per direction.

Apparatus and methods are presented for performing polarisation-sensitive optical coherence tomography measurements of a sample utilising polarisation-diverse illumination. A plurality of sets of one of more measurements of a volume of a sample, such as the anterior segment or retina of a human eye, are made with the sample volume illuminated with multi-wavelength light of different polarisation states. The plurality of sets of one or more measurements are processed to generate a plurality of tomographic volume images of the sample, each of the images being of the sample illuminated with light of a different polarisation state. The plurality of tomographic volume images may for example be processed to generate a three-dimensional representation of a polarisation property of the sample, or a polarisation-independent image of the sample. In certain embodiments the polarisation of the illumination is controlled using one or more rotatable wave plates, such as a rotatable quarter wave plate.

To provide a light interference distance measuring sensor that can appropriately recognize peaks of rays of interference light and measure distance with high accuracy.SOLUTION: A light interference distance measuring sensor 100 comprises: a wavelength sweep light source 110 that projects light while continuously changing its wavelength; an interferometer 120 that includes a branching unit 121 that branches light projected from the wavelength sweep light source and irradiates a plurality of spots of an object to be measured with the light, and for the rays of branched light, generates rays of interference light based on measurement light with which the object to be measured is irradiated and reflected on the object to be measured, and reference light traveling through an optical path at least partially different from the measurement light; a light receiving unit 130 that receives the rays of interference light; and a processing unit 140 that associates detected peaks and spots in the rays of interference light with each other to calculate the distance to the object to be measured. The rays of light branched in correspondence with the plurality of spots are set to have optical path length differences between the measurement light and the reference light different from each other.SELECTED DRAWING: Figure 10

A signal processing device (19) executes a phase connection process step of performing a phase connection process on a position in a space and a phase value at each of a plurality of times, a first correction step of performing outlier correction of a phase value for each position in the space in a predetermined direction of the space at a predetermined time among the plurality of times based on a result of the phase connection process, and a second correction step of correcting a phase value at a time other than the predetermined time for each of correction target positions in the first correction step among positions in the space.

A stage device includes a stage capable of moving in a first direction and a second direction orthogonal to each other, a scale arranged in the stage so as to extend in the first direction, an optical assembly arranged so as to face the scale in at least a part of a movable range of the stage and extending in the second direction, and an interferometer configured to transmit measurement light and reference light to the optical assembly, and receive the measurement light and the reference light returning from the optical assembly. The optical assembly is configured to apply the measurement light from the interferometer to the scale, and return the measurement light returning from the scale and the reference light to the interferometer.

A system may include a broadband light source emitting polarized light that is polarized to two orthogonal polarization states, multiple beam splitters for combining and splitting the polarization states, and interferometric cell for creation of interference patterns with respect to a sample surface, lenses of appropriate design that focus the polarized light at predefined locations, and sensors that analyze the polarized light as a function of angle and wavelength. The system may also include a controller configured to modulate the reference arm through operation of an optical chopper and allow for different data analysis modes to be used on the system produced data.

This disclosure relates to an inertial sensor for measuring an inertial quantity along a sensing axis. The sensor comprises an atom interferometer comprising a pulse generator to generate one or more pulsed light beams, defined by a respective pulse duration to place atoms into a superposition, and re-combine the atoms to measure an interference of the atoms and calculate the inertial quantity based on the measured interference. The sensor further comprises an auxiliary acceleration sensor configured to measure acceleration transverse to one or more of the pulsed light beams; and a control system configured to calculate a transversal offset of the atoms relative to the pulsed light beams caused by the measured acceleration transverse to the one or more of the light beams, increase the pulse durations, and adjust the pulse timings to compensate for a reduced beam intensity applied to the atoms as a result of the transversal offset.

A method for determining the position of a target reflector in a measurement range by differential optical interferometry includes several steps: a coherent source beam is generated using a single-frequency laser, where the coherent source beam is modulated between a first wavelength and a second wavelength; a light beam and a delayed beam are generated from the coherent source beam, where the delayed beam includes a delay relative to the light beam; the light beam is preferably arranged parallel to (and spatially separated from) the delayed beam; each of the light beam and the delayed beam is separated into a first portion and a second portion, where the second portion is arranged parallel to (and spatially separated from) the corresponding first portion; a first optical signal is generated by directing a first portion of one of the light beam and the delayed beam along a first path that includes the target reflector; and a second optical signal is generated by directing a second portion of one of the light beam and the delayed beam along a second path that includes a reference reflector, where the second path is arranged parallel to (and spatially separated from) the first path. A third optical signal is generated by directing a first portion of another one of the light beam and the delayed light beam along a third path. A fourth optical signal is generated by directing a second portion of another one of the light beam and the delayed light beam along a fourth path, the fourth path being positioned parallel to (and spatially separated from) the third path. A first interference signal is generated between the first optical signal and the third optical signal. A second interference signal is generated between the second optical signal and the fourth optical signal. The position of the target reflector is determined based on the first and second interference signals.

A laser interferometer includes: a laser light source configured to emit first laser light; an optical modulator including a vibration element that generates a vibration component in a direction intersecting an incident surface of the first laser light, and configured to modulate the first laser light by using the vibration element to generate second laser light including a modulation signal; a photodetector configured to receive the second laser light and third laser light that includes a sample signal generated by the first laser light being reflected by an object, and output a light reception signal; a demodulation circuit configured to demodulate the sample signal from the light reception signal based on a reference signal; and an oscillation circuit configured to operate using the vibration element as a signal source and output the reference signal to the demodulation circuit.

To provide a laser interferometer capable of more properly demodulating a Doppler signal derived from a measuring object irrespective of vibration conditions of a vibration element.SOLUTION: The laser interferometer comprises: a light source emitting a laser beam; an optical splitter splitting the laser beam emitted from the light source into a first optical path and a second optical path; an optical modulator including a vibration element provided on the first optical path or the second optical path and vibrating by current flowing, and modulating the laser beam using the vibration element; a light receiving element receiving a laser beam reflected by a measuring object provided on the first optical path or the second optical path to output a light receiving signal; and a demodulator circuit demodulating a Doppler signal derived from the measuring object from the light receiving signal on the basis of a reference signal and a modulation signal. Iq / f≤1×10-7 is satisfied when an amplitude value of the current flowing through the vibrating vibration element is denoted by Iq[A] and a vibration frequency of the vibration element is denoted by f[Hz].SELECTED DRAWING: Figure 1

An interferometric displacement measurement apparatus (100) includes at least one measurement interferometer (103) for measuring a change in optical path difference between a measurement beam (150) and a reference beam. A light source module (118) is arranged to generate a modulated light beam, having a particular optical spectrum, from which the measurement beam and reference beam are derived. A data acquisition and analysis module (105) can determine a measure representative of the displacement using interference intensity data received from a photodetector (111) which detects the interference of the measurement beam with the reference beam.

The invention provides a position measurement system, comprising: a light source to provide a measurement beam and a reference beam propagating along a common light beam path, an optical device located in the common light beam path and downbeam of the light source, wherein the optical device is configured to induce or adjust an offset between the measurement beam and the reference beam, interferometer optics downbeam of the optical device, the interferometer optics configured to propagate the measurement beam in multiple passes along measurement paths to a measurement surface and the reference beam in multiple passes along reference paths to a reference surface, a detector to receive a reflected measurement beam and a reflected reference beam after a final pass of the multiple passes, wherein a reflective surface in the measurement paths or the reference paths is tilted, such that an incident angle of the measurement beam or reference beam incident on the respective reflective surface is at a non-90 degrees angle and at a non-45 degrees angle with respect to the reflective surface.