183results 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.

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.

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.

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.

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 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.

The present disclosure relates to an inertial sensor for measuring an amount of inertia along a sensing axis. The sensor includes an atom interferometer including a pulse generator for generating one or more pulsed light beams defined by respective pulse durations to place atoms in superposition and recombine the atoms to measure interference of the atoms, the one or more pulsed light beams being configured to generate one or more pulsed light beams, the one or more pulsed light beams being defined by respective pulse durations, the one or more pulsed light beams being defined by respective pulse durations, and the one or more pulsed light beams being defined by respective pulse durations, the one or more pulsed light beams being defined by respective pulse durations. And calculating the amount of inertia based on the measured interference. The sensor further includes 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 lateral offset of the atoms relative to the pulsed light beam caused by the measured acceleration transverse to the one or more of the light beams, increase the pulse duration, and adjusting the pulse timing to compensate for a reduced beam strength applied to the atoms due to the lateral offset.

A method of rapid coherent synthetic wavelength interferometric absolute distance measurement includes receiving, from an optical system, an image from an object scene of at least two distinct wavelengths of light, each wavelength's light source having a coherence length greater than a desired ambiguity length of the absolute distance measurement, and whose synthetic wavelength in combination provides the desired ambiguity length of the absolute distance measurement. A phase-based approach, a magnitude-based approach, or an envelope of the magnitude-based approach can be taken to determine an interference between light returning from the object scene and light traversing a separate reference arm path of the optical system and calculate an optical distance to an object in the object scene.

A method for determining a position by differential optical interferometry of a target reflector in a measurement range comprises the following steps. A first, a second and a third coherent light beam is generated at a first wavelength at a first instance and at a second wavelength different from the first wavelength at a second instance. A first reference signal is generated by guiding the first coherent light beam along a first optical path having a first optical path length, a measure signal is generated by guiding the second coherent light beam along a second optical path having a second optical path length and comprising a target reflector, and a second reference signal is generated by guiding the third coherent light beam along a third optical path having a third optical path length, wherein the third optical path length is different from the first and second optical path length. A common delay is provided between generating the second reference signal and generating the first reference signal and between generating the second reference signal and generating the measure signal. A first interference signal is generated from the first reference signal and a first portion of the second reference signal at the first instance and at the second instance. A second interference signal is generated from the measure signal and a second portion of the second reference signal at the first instance and the second instance. A first and a second amplitude of the first and second interference signal are determined, respectively. A first signal is generated based on the first interference signal and the first amplitude. A second signal is generated based on the second interference signal and the second amplitude. A position of the target can be determined by calculating a difference between the first optical path length and the second optical path length based on the first and the second signal both in the first and the second instance.

This phase-quadrature interferometer (1) with polarization-maintaining optical fibers, each comprising a first axis and a second axis with different refractive indices, the interferometer (1) comprising a starting optical fiber (9) optically connecting, via its first axis, a linearly polarized laser source (3) and a first coupler (5), a reference optical fiber (11) optically connecting, via its first axis, the first coupler (5) and a second coupler (7), a measurement optical fiber (15) optically connected to the second coupler (7), a fourth optical fiber (43) and a fifth optical fiber (45) exiting the second coupler (7) to a phase-shifting module (47), and four optical sensors (49) configured to perform a phase-quadrature measurement of the light intensity received by the optical sensors (49). Figure for the abstract: Fig. 1

The invention refers to a measurement module (10) for a laser processing apparatus (1) in which a first optical path (P1) and a second optical path (P2) are defined for laser light within a housing (11). The first optical path (P1) has a fixed predefined optical path length. The second optical path (P2) is defined between a connection port (12) of the housing and a coupling port (14) and has a variable optical path length adjustable by an optical path length regulator system (20). The invention further refers to an interferometer system comprising a measurement module with a first optical path (P1) corresponding to a reference arm of the interferometer system and with a second optical path (P2) corresponding to an object arm of the interferometer system, wherein an optical path length regulator system (20) is configured for adjusting an optical path length of the second optical path (P2), i.e., of the object arm of the interferometer system. The measurement module (10) further comprises a focusing device (18) arranged in the second optical path (P2) between the connection port (12) and the optical path length regulator system (20) and configured for focusing the laser light transmitted through the second optical path (P2). The invention further refers to a laser processing apparatus (1) comprising a laser processing module (30) for laser-processing a workpiece (P) on a work field (37) using a work beam (W) and a measurement module (10) according to the invention.

Disclosed is a phase detection device using phase shifting, the device including a geometric phase optical element. According to one aspect of the present embodiment, provided is a phase detection device characterized by comprising an optical mask for phase-shifting object light and reference light having different circular polarizations and generated through an interferometer, wherein the optical mask comprises: an optical array including geometric phase optical pixels that phase-delay the object light and the reference light by twice a predetermined optical axis rotation angle; and a circular polarization beam splitter which is configured to transmit some of circular polarization component transmitted through the optical array.

An OCT instrument operable to acquire a B-scan representing a section of a sample, the sample being inclined relative to a plane normal to an axial direction along which depth information of the B-scan is acquired, the OCT instrument being configured to: split light from a swept light source into signal light and reference light; receive signal light reflected from scan locations on the sample; generate sideband light by adjusting an optical frequency of the reference light; sample, for each scan location, a respective time-varying interference signal resulting from interference between the sideband light and the received signal light; generate the B-scan from the sampled signals; and control the optical frequency during the scan such that an image of the sample in the B-scan is less inclined to a lateral direction in the B-scan than in a B-scan of the section acquired by the OCT instrument without the control.

Methods and systems for materials inspection are configured to perform optical coherence tomography (OCT) on a material. A power regulating device (21) in a reference arm (20) is controlled by a control logic (40). Generated OCT image data is evaluated in a computer-aided manner in order to identify and / or classify defects in the material.

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.

To provide a device for interferometric interval measurement.SOLUTION: A device for interferometric interval measurement includes a multi-wavelength light source that supplies a bundle of rays of at least three different wavelengths. The device includes an interferometer unit that splits the bundle of rays into a measurement bundle of rays and a reference bundle of rays. The measurement bundle of rays propagates to a measuring reflector movable along a measurement axis and the reference bundle of rays propagates to a fixed reference reflector, and both are reflected backward. The backward-reflected measurement bundle of rays and reference bundle of rays overlap while interfering in an interference bundle of rays. The interference bundle of rays is divided by a detection unit, a plurality of phase-shifted partial interference signals for each wavelength are generated. A signal processing unit determines absolute position information about the measuring reflector from the partial interference signals with different wavelengths and an additional rough position signal. In order to generate the additional rough position signal, the device has a modulation unit. The modulation unit applies phase modulation to an emitted wavelength, and a phase-modulated bundle of rays propagates in a direction of the interferometer unit and induces a spacing-dependent modulation in the partial interference signal.SELECTED DRAWING: Figure 1

A computer-implemented image processing method for removing complex conjugate image data from image data in real-time using dispersion comprising receiving an image signal comprising image data including complex conjugate image data (902), performing baseline signal subtraction (906), resampling wavelength data to generate linear wavenumber image data (908, 910), processing the linear wavenumber image data to generate a complex conjugate resolved, CCR, result using at least one iteration of a CCR image processing algorithm (912), and computing a CCR image from the CCR result (914); and separating the resulting CCR image from the received OCT image data to remove the complex conjugate image data. The method may be performed in real-time and may use phase or magnitude data or a synthesis of the two when generating the image data from the CCR result.

A high-dispersion single-mode hybrid optical fiber (1900) located in one of the reference arm or probe arm of an optical interferometer, wherein the hybrid fiber (1900) comprises at least two optical fibers (1902,1902), at least one of the at least two optical fibers having a different core diameter and at least one of the at least two optical fibers having different dispersion characteristics, the at least two optical fibers being fused together at their ends to form a hybrid optical fiber, and each of the at least two optical fibers having a length based on the core diameter of the optical fiber with respect to the central wavelength of the light beam passing through the hybrid optical fiber and a target GDD per unit length based on the target length of the hybrid optical fiber, wherein the hybrid optical fiber adds an additional GDD value compared to an optical fiber in the other of the reference arm or probe arm of an optical interferometer.

To provide a laser interferometer that includes an optical modulator that can modulate the frequency of a laser beam without using a diffraction grating, and reduces cost.SOLUTION: A laser interferometer comprises: a laser beam source that emits a first laser beam; an optical modulator that includes a vibration element having a vibration component in a direction intersecting an incident surface of the first laser beam, and modulates the first laser beam by using the vibration element to generate a second laser beam including a modulation signal; a light receiving element that receives the second laser beam and a third laser beam generated through reflection of the first laser beam on an object and including a sample signal, and outputs a light reception signal; a demodulator circuit that demodulates the sample signal from the light reception signal based on a reference signal; and an oscillation circuit that operates the vibration element as a signal source, and outputs the reference signal to the demodulator circuit.SELECTED DRAWING: Figure 2

To improve accuracy of FMCW LIDAR signals.SOLUTION: A light detection and ranging (LIDAR) system includes a LIDAR measurement unit, a reference measurement unit, and a phase cancellation unit. The LIDAR measurement unit estimates a travel time of a laser beam. The reference measurement unit determines a phase of a laser source. The phase cancellation unit identifies phase noise and cancels the phase noise from the laser beam, based at least partially on the phase of the laser source and the travel time of the laser beam. The denoised signal is used to determine a distance between a laser source and a target.SELECTED DRAWING: Figure 3a

An optical displacement sensor (2) comprises a reflective surface (4) and one or more diffraction gratings (6) which, together with the reflective surface, each define a respective interferometric arrangement. The reflective surface (4) is moveable relative to the diffraction grating(s) (6) or vice versa. Light from a light source (8) propagates via the interferometric arrangement(s) to produce an interference pattern at a respective set of photo detectors (10). Each interference pattern depends on the separation between the reflective surface (4) and the respective grating (6). A collimating optical arrangement (14) at least partially collimates the light between the light source (8) and the diffraction grating(s) (6). For the or each interferometric arrangement, when the reflective surface (4) or the diffraction grating (6) is in a zero-displacement position, the optical path length L of the light propagating between the diffraction grating (6) and the reflective surface (4) satisfies the relationship: to within 20% of j, where n is an integer; where Tz is the Talbot length, defined by: where λ is the wavelength of the light, and where p is the grating period of the respective diffraction grating (6). Alternatively, L may satisfy: to within 20% of p where m is an odd integer. Additionally or alternatively, the optical displacement sensor (34; 112) may comprise two or more diffraction gratings (44, 46; 116) and may be configured to provide a respective separate light beam (62, 64; 132) to each grating (44, 46; 116) using a beam-separating arrangement (48; 126) or plural light source elements.

A method for determining the position of a target reflector in a measurement range by differential interferometry comprises the following steps: First, second, and third coherent light beams are generated at a first instant at a first wavelength and at a second instant at a second wavelength different from the first wavelength; a first reference signal is generated by directing the first coherent light beam along a first optical path having a first optical distance; a measurement signal is generated by directing the second coherent light beam along a second optical path having a second optical distance and including the target reflector; and a second reference signal is generated by directing the third coherent light beam along a third optical path having a third optical distance, the third optical distance being different from the first and second optical distances. A common delay is provided between generating the second reference signal and the first reference signal, and between generating the second reference signal and the measurement signal. A first interference signal is generated from a first portion of the first reference signal and a first portion of the second reference signal at a first time instant and a second time instant. A second interference signal is generated from a second portion of the measurement signal and a second reference signal at a first time instant and a second time instant. A first amplitude and a second amplitude of the first interference signal and the second interference signal are determined, respectively. A first signal is generated based on the first interference signal and the first amplitude. A second signal is generated based on the second interference signal and the second amplitude. The position of the target can be determined by calculating a difference between the first optical distance and the second optical distance based on the first signal and the second signal at both the first time instant and the second time instant.