374results 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 demodulation system for optical fiber Fabry-Perot sensor, including: a light source; a Fabry-Perot sensor; a coupler; a first optical component configured to shape interference light into a linear first interference fringe pattern; a second optical assembly configured to form a second interference fringe pattern; a first detector configured to receive a first light signal to form a first light signal curve; a second detector configured to receive a second light signal to form a second light signal curve; a data collection device configured to receive the first light signal curve from the first detector to generate a first light intensity curve, and receive the second light signal curve from the second detector to generate a second light intensity curve; and a processor configured to calculate a cavity length variation of the Fabry-Perot sensor on the basis of the first light intensity curve and the second light intensity curve.

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.

An optical interference distance measuring sensor is provided with a plurality of light receiving channels corresponding to one light projecting channel, and can improve resistance to interference. A light interference distance measuring sensor according to one embodiment of the present invention is provided with: a light source that projects light while changing the wavelength; an interferometer that generates interference light based on the measurement light and the reference light; a light receiving unit that receives the interference light from the interferometer and converts the interference light into an electric signal; and a processing unit that calculates the distance from the sensor head to the measurement object, the interferometer comprising: a light projection channel configured so as to propagate light supplied from the light source toward the sensor head and to irradiate the measurement object from the sensor head; and a plurality of light-receiving channels configured to receive the measurement light and propagate the measurement light toward the light-receiving unit, the light-projecting channel and / or the plurality of light-receiving channels further propagating the reference light.

An optical source is configured to simultaneously generate a set of four time-correlated photons comprising a first pair of photons and a second pair of photons. An interferometer is configured to receive a photon from the first pair of photons and configured to receive another photon from the first pair of photons. A first and a second detector configured to generate an electrical signal in response to measurements of an output of the interferometer. A third detector is configured to generate an electrical signal in response to measurement of a photon from the second pair of photons. A fourth detector is configured to generate an electrical signal in response to measurement of another photon from the second pair of photons. A processor is configured to determine a coincidence of the generated electrical signals in response to measurements of the second pair of photons, thereby identifying the set of four time-correlated photons and heralding an interferometric measurement from the generated electrical signals of the first and second detectors.

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.

A distance measurement device and method based on secondary mixing of inter-mode self-interference signals of optical frequency combs are provided, which relate to the field of high precision laser distance measurement technologies. A dual-comb light source emits a dual-comb laser into a detection optical module to obtain the inter-mode self-interference signals carrying the to-be-measured distance information. The detection optical module outputs the inter-mode self-interference signals into a generation, acquisition and calculation module of inter-mode self-interference secondary mixing signals to generate the inter-mode self-interference secondary mixing signals, to thereby achieve signal acquisition and obtain a distance measurement result. In this device, coarse and fine distance measurements at different scales are achieved, measurement range and accuracy can be effectively balanced by combing intermediate transition measurement scales and inter-stage transition method, strong real-time property of measurement is achieved, and the light source has low cost and the scale of the system is small.

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.

Compact and robust machine vision systems are provided herein. A machine vision system includes an optoelectronic system configured to emit measurement beams towards objects and a motion module configured to move the objects and / or components of the optoelectronic system. The machine vision system uses the relative motions to reduce degrees of freedom required to sample the objects to produce 3D images. The optoelectronic system includes a light source configured to emit a beam and sweep its frequency. The optoelectronic system includes primary interferometers configured to measure distances to points of an object and auxiliary interferometers configured with reference delays. The optoelectronic system includes electronic circuitry configured to interpret outputs of the interferometers into distance measurements by simpler computations in the time domain. The electronic circuitry is configured to measure frequency integrals of the interferometers and determine the distance measurements by comparing the measured frequency integrals.

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.

A bidirectional Littrow two-degree-of-freedom grating interference measurement device based on double gratings includes a transmission two-dimensional grating and a reflection two-dimensional grating. A dual-frequency laser emitted by a light source passes through the transmission two-dimensional grating with a specific grating pitch to form four beams in X direction and Y direction, the four beams are incident on the reflection two-dimensional grating at a Littrow angle, and the four beams diffracted by the reflection two-dimensional grating return to the transmission two-dimensional grating in an incidence direction along the same path; different orders of transmission light of the four beams of light in different directions may form stable interference signals carrying displacement information, and the stable interference signals are received by a detector.

A laser interferometer includes: a laser light source configured to emit laser light; a light shielding element having an opening through which the laser light passes; an optical modulator configured to modulate the laser light into reference light having a different frequency; and a light receiving element configured to receive object light generated by reflecting the laser light by an object to be measured and the reference light and output a light receiving signal. 0.10≤φpin≤10.0, in which φpin [mm] is a diameter of the opening.

A line-field swept-source optical coherence tomography (OCT) system features a cat's-eye tunable laser that is free-space coupled to an interferometer. The laser employs a single angled facet (SAF) edge-emitting gain chip producing a beam with multiple spatial modes. By preserving these higher-order modes through free-space coupling—avoiding single-mode fiber— the system generates a line with a more uniform, top-hat intensity profile when projected onto a sample, such as a patient's retina. This profile mitigates the Gaussian power roll-off typically associated with single spatial mode beams, ensuring adequate signal-to-noise ratio across the line while adhering to optical safety limits. The laser cavity includes a thin-film interference bandpass filter mounted on an angle control actuator, allowing for wavelength sweeping by tilttuning the filter. The system integrates a line-scan sensor and is designed for manufacturability, offering improved imaging quality for ophthalmic diagnostics and other applications requiring high-resolution, cross-sectional imaging.

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 heterodyne interferometer system comprises: a first light source providing a first laser beam having a first frequency f1; a second light source providing a second laser beam having a second frequency f2 which differs from the first frequency; a combiner for polarizing the first and second laser beams and for providing an input beam wherein the polarized first and second laser beams are combined; an optical resonator cavity comprising an odd number of at least partially reflective mirrors arranged in the cavity for reflecting and circulating the input beam in the cavity, the cavity being adapted for receiving the input beam and providing an output beam comprising a first spatial mode having the first frequency f1 and a first polarization and a second spatial mode having the second frequency f2 and a second polarization which differs from the first polarization; and a heterodyne interferometer for receiving the output beam.