510results about "Interferometers" patented technology

Methods and systems are provided to generate and use pairs of highly nondegenerate frequency-entangled photons for Hong-Ou-Mandel interferometric measurement of local or remote samples. The use of highly nondegenerate frequency-entangled photon pairs enables ultra-high spatial resolutions even in the presence of background noise, dispersive intermediate media and / or dispersive or multi-interface targets, and high probe photon losses. The use of highly nondegenerate, narrow-band, frequency-entangled photon pairs for interferometric measurement of distance also allows the interferometer to be calibrated more easily for the two (or more) discrete narrow bands of wavelengths represented by the photon pairs. The use of narrow-band nondegenerate frequency-entangled photon pairs also permits improved noise rejection and increased fidelity in coincidence detection.

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.

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.

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.

Systems, devices and methods for measuring surface roughness and surface shape of an optical element using a dual-mode interferometer are disclosed. The devices implement optical filters, with a compact form, that allows measurement of both surface characteristics without rearranging the system components. One example interferometric system includes a laser light source and a low coherence light source that alternatively provide light to a collimator, followed by a polarizer, and a polarizing beam splitter. The system further includes two optical filters, a quarter waveplate, two objectives and a reference optical component. Each light source produces a set of interferograms, where one set of interferograms is used to measure the surface shape and another set of interferograms is used to measure the surface roughness of the optical component.

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.

The invention discloses a super-resolution microscopic interference measurement method based on broadband annular radial polarized light, which comprises the following steps of: selecting a broadband spectrum extended surface light source, providing uniform illumination covering a field of view to be measured and having a certain aperture angle by adopting a Kohler illumination system, and designing a two-stage relay system, amplitude and polarization modulation of the full-view-field light beam is realized through the liquid crystal spatial light modulator and the vortex wave plate; the expanded surface light source and the large-numerical-aperture microscope objective are combined to focus broadband annular radial polarized light, so that super-resolution microscopic interference imaging of the sample is realized; the super-resolution morphology measurement of the microstructure surface is realized in combination with a phase shift coherent method, the problem of low efficiency caused by traditional laser spot scanning is solved, the transverse resolution limitation of traditional microscopic interference morphology measurement is broken through, and the morphology resolution of traditional microscopic interference measurement is improved.

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.

A self-mixing interferometric laser sensor (100) comprises a vertical cavity surface emitting laser, VCSEL, (10) configured to emit laser radiation (9) with a linear polarization (90) through an emission surface (14), a first photodetector (21) configured to monitor a first part (91) of the laser radiation (9) and to output a first signal (1), a first linear polarizer (23) arranged in front of the first photodetector (21) such that the first part (91) of the laser radiation (9) passes through the linear polarizer (23) before reaching the first photodetector (21), a second photodetector (22) configured to monitor a second part (92) of the laser radiation (9) and to output a second signal (2), a second linear polarizer (24) arranged in front of the second photodetector (22) such that the second part (92) of the laser radiation (9) passes through the second linear polarizer (24) before reaching the second photodetector (22), wherein the first linear polarizer (23) is oriented at a first angle (71) with respect to the linear polarization (90) of the VCSEL (10), wherein the second linear polarizer (24) is oriented at a second angle (72) with respect to the linear polarization (90) of the VCSEL (10), wherein the first angle (71) is substantially +45° and the second angle (72) is substantially -45°.

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.

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 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 laser interferometer includes a light source that emits first laser light, an optical modulator that includes a vibrator and modulates the first laser light by using the vibrator to generate second laser light including a modulated signal, a photodetector that receives interference light between third laser light including a sample signal generated by reflecting the first laser light on an object and the second laser light to output a light reception signal, a demodulation circuit that demodulates the sample signal from the light reception signal based on a reference signal, and an oscillation circuit that outputs the reference signal to the demodulation circuit, and the vibrator is a signal source of the oscillation circuit.

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.

Systems capable of in situ position detection, thickness and refractive index measurement, and / or focus control, are provided. The systems may include a first laser emitting device, a first lens, a first beam splitter and a second lens respectively forming an optical path. The second lens, the first beam splitter, a third lens, and an image detection and processing module (that includes a sensor, such as a photodiode) may form an optical return path. The second lens may be configured to continuously oscillate, as a function of time, a focal position of a laser from the first laser emitting device. The image detection and processing module may be configured to receive a reflected beam, send information related to the received beam to processing units(s), which may be configured to receive the information and determine one or more surface positions based on a temporal response of the information.

In some embodiments, systems, methods, and media for multiple reference arm spectral domain optical coherence tomography are provided which, in some embodiments, includes: a sample arm coupled to a light source; a first reference arm having a first path length; a second reference arm having a longer second path length; a first optical coupler that combines light from the sample arm and the first reference arm; a second coupler that combines light from the sample arm and the second reference arm; and an optical switch comprising: a first input port coupled to the first optical coupler; a second input coupled to the second coupler via an optical waveguide that induces a delay at least equal to an acquisition time of an image sensor; and an output coupled to the image sensor.

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.