566 results about "Reference beam" patented technology

A terminal according to one aspect of the present disclosure includes a transmitting section that transmits a plurality of repetitions of a physical random access channel by using a plurality of different beams, and a control section that determines a reference beam corresponding to one of the plurality of different beams and that determines, on the basis of reception of a response to the physical random access channel, a subsequent uplink beam, the reception using the reference beam. According to one aspect of the present disclosure, it is possible to improve coverage in a random access procedure.

A LiDAR apparatus, including: a laser to generate an optical signal; modulation components configured to receive the optical signal as an input and to output at least two corresponding modulated optical signals at respective output ports, wherein each modulated optical signal is modulated by a corresponding pseudo-random bit sequence, and: (i) the optical signals have respective different delays such that the modulations do not overlap in time; or (ii) the pseudo-random bit sequences have low cross-correlation; for each of the at least two modulated optical signals, a corresponding optical transmitter configured to transmit the corresponding modulated optical signal towards a corresponding surface spaced from the LiDAR apparatus by a corresponding distance, and a corresponding optical receiver configured to receive a portion of the transmitted optical signal scattered and / or reflected by the surface, the received portion of the optical signal having a phase shift and / or Doppler shifted angular frequency due to radial motion of the LiDAR apparatus relative to the surface; at least one photodetector to receive the optical signals received by the optical receivers, interfered with a reference beam, and to generate a corresponding output signal; at least one analogue to digital converter to generate a digital signal representing the output signal from the at least one photodetector; and a digital signal processing component configured to process the digital signal to generate LiDAR data representing the distances to the surfaces and / or relative velocities of the surface(s) with respect to the apparatus.

The invention provides an optical image encryption method and system based on a partially coherent non-diffracting light beam, and belongs to the technical field of optical encryption and information transmission. Encoding to-be-encrypted image information into the light field cross-spectral density function; the method specifically comprises the following steps: discretizing an image as an expansion coefficient of a power spectral density function at a light source under a pseudo-mode substrate, and constructing a cross spectral density function; a complex amplitude modulation algorithm is adopted to convert light field complex amplitude distribution into a pure phase hologram, the pure phase hologram is loaded to a spatial light modulator, a multi-mode incoherent superposition partially coherent non-diffraction light beam is generated, and the multi-mode incoherent superposition partially coherent non-diffraction light beam interferes with a reference light beam to obtain a light field image; performing coordinate transformation and frequency domain filtering on the light field image to extract a complex coherence degree function; and reconstructing and restoring the original image information in combination with a preset key and a digital inversion algorithm. According to the method, the light beams are constructed based on pseudo-mode superposition, image hidden coding, transmission and decryption are realized by utilizing the characteristics of partially coherent light and non-diffraction light beams, and the method is suitable for optical communication and security information transmission.

The invention relates to the cross technical field of atmospheric science and communication technology, in particular to an atmospheric refraction and waveguide environmental parameter detection and prediction method and device, and the method comprises the following steps: carrying out the power distribution of a light beam of a broadband light source through employing a light splitting element based on the emission of the broadband light source, and forming a detection light beam and a reference light beam, and guiding the detection light beam to pass through a preset open atmosphere optical path, and guiding the reference light beam to pass through a known refractive index stabilizing medium or a vacuum pipeline. The detection light beam and the reference light beam are formed through light splitting of the broadband light source, the detection light beam penetrates through the open atmosphere path, the reference light beam passes through the stable medium, Fourier transform is carried out on interference signals of the two light beams to extract wavelength phase difference mapping data, and tiny optical path change caused by atmospheric refractive index disturbance can be captured. Compared with the traditional single-point or single-path measurement, the sensing sensitivity and the measurement dimension of the atmospheric refractive index spatial nonuniformity are improved by using the broadband spectral information.

The invention discloses an automatic calibration method and system for a mining laser gas detector, and relates to the technical field of instrument calibration. The method comprises the following steps: dividing detection beam parameters into measurement beam parameters and reference beam parameters; enabling the measurement light beam parameter to penetrate through the to-be-measured gas area to obtain a measurement signal, and enabling the reference light beam parameter to penetrate through the reference gas chamber to obtain a reference signal; performing photoelectric conversion calculation on the reference signal to obtain a gas concentration detection value; the gas concentration detection value is compared and analyzed with a reference data value according to the central wavelength position of the mining laser gas detector, and a calibration unit is activated according to a comparison result; and automatically correcting the mining laser gas detector, generating a correction parameter set, calculating a measurement signal, and generating a concentration value of the gas to be detected. The technical problems of low calibration efficiency and unstable calibration precision of the mining laser gas detector in the prior art are solved, and the technical effects of realizing automatic calibration of the mining laser gas detector and improving the calibration efficiency and precision are achieved.

The invention provides an optical measurement method and device, and belongs to the technical field of optical measurement, and the method comprises the steps: starting a light source with the wavelength changing dynamically to generate a sweep frequency optical signal; dividing the light into a measuring beam and a reference beam by using a light splitting component, guiding the measuring beam to irradiate a target to be measured and then return along the same path, and guiding the reference beam to enter an optical component of which the optical path changes along with the wavelength and then return; based on the low-coherence characteristic of the light source, when the optical paths of the two light beams meet the interference condition, detecting an interference signal by using a sensing component; the optical path difference is determined according to time information in the interference signal, and the thickness of each reflection interface is calculated by combining refractive index data of a target to be measured. Different from the traditional low-coherence interference measurement which depends on a motor and the like to control the movement of a reflector, the method avoids the limitation of mechanical driving on the measurement frequency, and achieves the high-speed optical thickness measurement.

The invention relates to an optical fiber coupling dynamic interferometer based on arrayed waveguide grating light splitting. A luminous source and an arrayed waveguide grating of the optical fiber coupling dynamic interferometer are arranged on a motion module. The light emitting source is connected to the input port of the array waveguide grating through an optical fiber, and through the movement module, any one of the multiple output ports of the array waveguide grating is in butt joint with the optical fiber connected to the incident end of the collimation structure. A half-wave plate and a beam splitter prism of the imaging element group are sequentially arranged on an emergent light path of the emergent end of the collimation structure, and the beam splitter prism is used for splitting a light beam passing through the half-wave plate into a reference light beam transmitted along a first light path and a measurement light beam transmitted along a second light path. And the reflecting mirror of the imaging element group reflects the reference light beam back to the beam splitting prism. And the to-be-measured surface reflects the measurement light beam back to the beam splitter prism. The reference beam and the measurement beam reflected back to the beam splitter prism interfere with each other and are imaged on the target surface of the camera. Accurate measurement of the wavefront image of the surface to be measured is realized.

A scanning imaging method includes splitting an optical beam into a reference beam and a scanning beam, generating an interference map, and processing the interference map to produce a reconstructed image of a sample. Generating the interference map includes, for each of a plurality of sections of the sample, generating a respective interference-map element of the interference map by: (i) illuminating the section with the scanning beam to generate a plurality of scattered beams, each scattered beam corresponding to a respective spatial frequency of the scanning beam, (ii) attenuating the reference beam, (iii) generating a plurality of interference signals at least in part by interferometrically combining the plurality of scattered beams and the attenuated reference beam while modulating a phase difference between the reference beam and the plurality of scattered beams, and (iv) detecting the plurality of interference signals to yield the respective interference-map element.

The invention provides a cavity adjusting method and device for a laser gyroscope resonant cavity, and the method comprises the following steps: building a light beam loop: horizontally placing a resonant cavity substrate on a supporting seat, and forming the light beam loop with two plane reflectors and two spherical reflectors; light beam introduction: starting a sweep frequency laser assembly, and enabling the reference light beam to enter a resonant cavity light path after passing through a light beam collimation system; light spot form monitoring and coarse adjustment: after a light beam emitted by the resonant cavity is collected by an image collector, the main control computer analyzes the light spot form and judges the imbalance state, evaluation information is fed back to the control system, the control system adjusts the inclination amount of the horizontal dimension and the pitching dimension of the light beam in the light beam collimation system according to the feedback information, and the light spot form is obtained. And the light spot is located at the center of the cavity mirror to finish coarse adjustment of the cavity. According to the method, coarse cavity adjustment can be completed without depending on a complex optical cavity technology, the cavity adjustment time is greatly shortened, the overall operation is simple, and the cavity adjustment efficiency is improved.

The invention discloses an inclined wave surface sub-aperture stitching interference detection method based on a spatial light modulator, and relates to the field of optical detection. Light emitted by the laser is collimated and expanded and then enters the polarizing beam splitter; the reflected light is used as a reference light beam, and the transmitted light is used as a test light beam; a test light beam enters the spatial light modulator, is subjected to phase modulation by the spatial light modulator, passes through the lens and then forms standard spherical waves with different inclination angles, and zero detection is carried out on sub-apertures divided in different regions. The spatial light modulator is used as an ideal point source array generator to be matched with the imaging lens, so that required ideal inclined spherical waves can be generated according to different parameters of a measured piece, and compared with a traditional point source generator, the device has high universality. And for a large-aperture complex curved surface, sub-aperture splicing can be realized without moving an interference device, and errors caused by mechanical movement are reduced.

The invention relates to a polarization correlation imaging scheme for extracting a target from objects which are made of the same material and have different roughness. The laser generates a Gaussian beam, and random speckles are generated through the rotary ground glass. A polarizer is placed behind the ground glass to control the polarization direction, and a beam splitter divides speckles into a test beam and a reference beam. The reference light beam is received by the CCD, and the test light beam is reflected after irradiating an object and is separated by the beam splitter. One beam of light is received by the barrel detector after passing through the + 45-degree polarizer, and the other beam of light is collected by the other two barrel detectors after passing through the polarization beam splitter. And the computer performs correlated imaging on the signals acquired by the barrel detector and the preset speckles. By modulating the polarization state of the light field and designing the receiving end, additional object surface polarization information is introduced, so that the system can extract a target from objects which are made of the same material and have different roughness, and the system has application value in a complex confrontation environment.

The invention discloses a displacement measurement system. The device comprises a laser, an integrated chip and a control module, the integrated chip comprises an optical waveguide structure, a beam splitting module and an optical signal modulation module; the laser is used for emitting a detection beam to the optical waveguide structure; the beam splitting module is arranged in the optical waveguide structure and on a propagation path of the detection light beam; the optical signal modulation module is arranged in the optical waveguide structure and on a propagation path of the reference light beam; the control module is in communication connection with the optical signal modulation module. According to the technical scheme, the optical waveguide structure, the beam splitting module and the optical signal modulation module are arranged in the integrated chip, the detection light beam enters the integrated chip for optical signal processing, then the control module is matched, a low-cost and small-sized displacement measurement system is formed, meanwhile, due to the fact that optical transmission is conducted in the optical waveguide structure, the measurement accuracy is improved, and the measurement precision is improved. And the reliability and the precision of the displacement measurement system are improved.

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.

The provided is a device for image based on FAPNN and a recognition method, comprising creating training transparent matrices corresponding to various discrete image categories in the training analog image dataset, recording each image for each image category by a Fourier convolution in one cell of the training transparent holographic matrix; generating different separate holographic cells on the 3D holographic memory matrix by simultaneously Fourier convolution of all images recorded on the training transparent holographic matrix; recording, with mechanical or optical change of the training transparent matrices, various image categories in different holographic cells of the 3D holographic memory matrix at different angles of reference beam and object beam; and receiving the analog image to be recognized, recognizing the image to be recognized and obtaining an image recognition result through values recorded in the holographic cells in the 3D holographic memory matrix.

A method for calibrating an optical sensor and / or a camera for a motor vehicle, wherein the optical sensor and / or the camera detects ambient light through a first pane (10) for the motor vehicle, the method comprising the following steps: receiving a first attenuation value of a first reference light beam reflected in a second pane (50) for a motor vehicle; receiving a second attenuation value of a second reference light beam passed through the second pane (50); transmitting a measuring light beam from a first side (12) of the first pane (10) into the first pane (10); receiving the measuring light beam reflected in the first pane (10) on the first side (12) of the first pane (10); determining a third attenuation value of the measuring light beam in the first pane (10) based on the transmitted measuring light beam and the received measuring light beam;and calibrating the optical sensor and / or the camera based on the first attenuation value of the second disc (50), the second attenuation value of the second disc (50) and the third attenuation value of the first disc (10);

The invention discloses a single-frequency pulse laser source multi-dimensional imaging system and method, and belongs to the technical field of laser radars. The imaging system comprises a single-frequency pulse laser source module, an optical imaging module, a frequency shift and phase modulation module, a time sequence control module and a data processing module, the single-frequency pulse laser source module emits a detection light beam, a first local reference light beam and a second local reference light beam, and the detection light beam irradiates a target to generate a reflection light beam; the time sequence control module controls the three light beams to perform synchronous frequency shift, so that the first local reference light and the reflected light beam are coherent in the optical imaging module to form a holographic image, and the second local reference light beam and the partially reflected light beam generate a beat frequency signal in the frequency shift phase modulation module; the data processing module analyzes the beat frequency signal so as to adjust the initial phase and frequency of outgoing of the detection light beam, and dynamic coherent imaging of the reflected light beam and the first local reference light in the optical imaging module is ensured; and real-time information of the holographic image is analyzed, and a high-quality three-dimensional image is reconstructed.

The invention provides a preparation method of a volume holographic element, the volume holographic element and an augmented reality 3D display device. The preparation method comprises the following steps: providing a pixelated diffractive lens array and a volume holographic material arranged adjacent to or adjacent to the pixelated diffractive lens array; wherein the pixelated diffraction lens array comprises target diffraction lens sub-units which are distributed in an array; at least one recording step is implemented, and the recording step comprises the steps that a recording light beam is projected to the pixelated diffractive lens array, and the recording light beam is irradiated to one side of the volume holographic material after being emitted by the pixelated diffractive lens array; and projecting a reference light beam to the other side of the volume holographic material, irradiating the reference light beam to the volume holographic material and interfering with the recording light beam to form holographic pixel units in one-to-one correspondence with the target diffraction lens sub-units. The volume holographic element prepared by the preparation method has high diffraction efficiency and high transmittance, and the presented 3D image also has the advantages of low crosstalk, no depth flipping, no self-repetition image and the like.

Certain aspects of the present disclosure provide a method for wireless communications by a user equipment (UE), generally including receiving a configuration indicating, for one or more reference signals (RSs), at least one bitmap indicating beam shape information and a reference beam direction corresponding to the bitmap, receiving dynamic signaling indicating that the UE is to update at least one of the bitmap or corresponding reference beam direction for at least one of the RSs, and updating the one of the bitmap or corresponding reference beam direction for at least one of the RSs based on the dynamic signaling.

An optical metrology device characterizes a test object using a phase shift interferometer with synchronous time varying optical frequency shifts. A light source generates a beam having a time varying frequency, which is divided into two collinear, orthogonally polarized beams that differ by a first frequency shift. One or more optical cavities receive the beams and produce a pair of reference beams that differ from each other in frequency by the first frequency shift and a pair of test beams with a second frequency shift induced by the one or more optical cavities. The test beams differ from each other by the first frequency shift and differ from the reference beams by the second frequency shift. The first frequency shift has a pre-defined relationship with respect to the second frequency shift to generate interference between a reference beam and test beam that have frequency shift magnitudes with the pre-defined relationship.

The invention relates to the technical field of optical element surface shape dynamic measurement scheme design, in particular to an element surface shape dynamic measurement system based on a metasurface. According to the scheme, polarized light emitted by a laser is split into reference light and test light, the test light passes through a quarter-wave plate twice to realize polarization orthogonalization, and the test light is combined with the reference light to form elliptically polarized light; synchronously capturing component intensities of left-handed / right-handed circular polarized light and orthogonal line polarized light by using a detector, and resolving a phase difference delta in real time by combining a Stokes parameter; environmental interference is eliminated based on a common-path design, a polarization beam-splitting element is omitted, and the architecture is simplified; accurate dynamic measurement of the surface shape of the measured piece is realized by deducting the inherent surface shape error of the system. The system provided by the invention has the advantages of strong anti-interference performance, high measurement efficiency, remarkable cost reduction and the like, and is suitable for precise optical manufacturing and on-line detection scenes.

The invention relates to the technical field of optics, in particular to blade front and tail edge polishing and correcting equipment which comprises a clamp for loading a to-be-detected guide vane, a polishing system is arranged beside the clamp, and the to-be-detected guide vane is vertically placed on the clamp; the system also comprises a laser interferometer system. The laser interferometer system comprises a laser and a beam splitter, and the beam splitter splits a measuring light beam and a reference light beam; linear collimating lenses are respectively arranged on light paths of the measuring light beam and the reference light beam, and the measuring light beam and the reference light beam respectively penetrate through the collimating lenses to form horizontal linear light beams. On-line real-time detection is achieved through the laser interferometer system, the defect portions of the front edge and the tail edge of the guide vane are accurately positioned, the polishing head can conveniently move to the defect portions to conduct fine polishing, the production period is shortened, and the production cost is reduced.

The invention provides a gas sensing system and method based on MZI-micro-ring resonant cavity enhancement. The gas sensing system comprises a laser, a beam splitter, a first coupling module, a second coupling module, an optical switch and a coherent detection module, a light source emitted by the laser passes through the beam splitter to obtain three identical light beams, including a reference light beam, a first signal light beam and a second signal light beam; wherein the first signal light beam and the second signal light beam respectively pass through the first coupling module and the second coupling module, are subjected to channel selection of the optical switch, and then are subjected to interference measurement with the reference light beam through the coherent detection module.

An optical coherence tomography (OCT) system comprises an interferometer configured to split incident light into a reference beam and a test beam, and to interfere the test beam reflected from the specimen with the reference beam reflected from a reference mirror to produce an interference pattern. The OCT system also comprises a spectrometer configured to analyze spectral components of the interference pattern at non-uniformly sampled wavenumbers. A computer-readable memory of the OCT system is configured to store a measurement model with elements connecting different depth values with different non-uniformly sampled wavenumbers and weighted with weights derived from a power spectral density (PSD) of the incident light for corresponding wavenumbers. The OCT system further comprises a processor configured to determine the profilometry measurements of the specimen as a maximum likelihood estimate of the specimen surface depth by back-projection of the measured intensities with the measurement model.

The invention discloses a pattern wafer multi-parameter synchronous detection system and method based on double optical combs, and belongs to the field of wafer quality detection. The system comprises a signal light path, a reference light path, a detection light path and a synchronous detection module. After interference, the detection light beam and the reference light beam are decomposed into an H path and a V path through the polarization beam splitter, and are synchronously detected by the first camera and the second camera. The invention also provides a method which comprises the following steps: synchronously acquiring two paths of time domain interference data; fourier transform is carried out on each pixel point to obtain a plurality of spectrum pairs; the processing unit decodes in parallel based on the spectrum pair, and synchronously inverts multi-dimensional physical parameters such as three-dimensional morphology, stress and film parameters of the pattern wafer; and finally, comparing and identifying defects. According to the method, the problems of low detection efficiency and single information dimension in the prior art are solved, and wide-field, high-speed, high-precision and multi-parameter synchronous comprehensive characterization is realized.

The invention relates to the technical field of interferometers, in particular to an interferometer light path calibration method and method.The interferometer light path calibration method comprises the steps that an interferometer is started, a measurement light beam and a reference light beam generated by the interferometer are combined through a polarization splitting prism and then are emitted towards an observation screen, and a measurement light spot and a reference light spot are formed on the observation screen; adjusting a reflector group of the interferometer to enable the measurement light spot to coincide with the reference light spot; the observation screen is removed, an optical fiber is connected, and the combined light beams are coupled into the optical fiber; the output end of the optical fiber is connected to detection equipment, a light current signal is obtained through detection of the detection equipment, and the ratio of an alternating-current voltage component to a direct-current voltage component is shown; and a lambda / 4 wave plate in the interferometer is adjusted until the ratio reaches a preset condition, and calibration is completed. The method is accurate and reliable, is simple and convenient to operate, has repeatability, can give consideration to space alignment and polarization matching, and facilitates the improvement of the stability and measurement precision of an interference system.

The invention relates to a reflectivity spectrum obtaining method, an end point detection method and device and a polishing device.The reflectivity spectrum obtaining method comprises the steps that an influence factor distribution curve representing light intensity measured value volatility under different light intensity light source conditions is obtained, a critical light intensity value corresponding to the dominant light source factor is determined based on the influence factor distribution curve, and the critical light intensity value is calculated according to the critical light intensity value. The source light beam is split according to a preset proportion beta to obtain a required measurement light beam and a reference light beam, and the measurement light beam enters a sample to form a reflection light beam; the reflected light intensity is calibrated based on the reference light intensity to generate a target reflected light intensity. And calculating the reflectivity spectrum of the sample based on the target reflection light intensity. Wherein the measuring light beam and the reference light beam have the same light intensity volatility, so that when the reflected light intensity is calibrated based on the reference light intensity, the accuracy and the stability of reflectivity spectrum measurement are effectively improved.

The invention relates to a of photoacoustic gas sensing apparatus (100) for sensing a gas sample in a sample chamber (310). The apparatus (100) comprises: a reference light source (220), configured for emitting a reference light beam (221) when driven by a reference power source (225), wherein the reference light beam (221) is configured for passing a reference chamber (320) filled with a reference gas and for reaching a detector chamber (400) filled with a detector gas; a sample light source (210), configured for emitting a sample light beam (211) when driven by a sample power source (215), wherein the sample light beam (211) is configured for passing the sample chamber (310) filled with the gas sample and for reaching the detector chamber (400); a microphone (500), configured for sensing pressure changes in the detector chamber (400), the pressure changes being a function of the gas sample; and a control unit (600), configured for receiving an electric output (560), caused by the pressure changes, from the microphone (500), and for controlling, depending on the electric output (560), an amplitude of the reference power source (225) and / or of the sample power source (215).

The invention discloses a two-degree-of-freedom displacement simultaneous measurement system and method based on an orbital angular momentum beam interferometer. The system comprises a laser; the light field regulation and control module is used for converting the linearly polarized light into a light beam with orbital angular momentum; an optical isolator; a first beam splitter; a second beam splitter; the third beam splitter is used for combining the first reference light beam and the first measurement light beam to generate conjugate interference; a fourth beam splitter; a fifth beam splitter; the sixth beam splitter is used for combining the second reference light beam and the second measurement light beam to generate conjugate interference; a seventh beam splitter; a first reflector; a second reflector; a third reflector; a first Weive prism; a second Weive prism; a reflection grating; and the image acquisition and processing module is used for acquiring a petal-shaped interference pattern formed by conjugate interference. The system is compact in structure and high in demodulation sensitivity, and can realize non-contact and high-resolution synchronous two-degree-of-freedom measurement.

A broadband interferometry system that includes (i) an interferometer that includes a tilted reference mirror that is oriented by a tilt angle in relation to a normal to an optical axis of a reference beam thereby introducing a range of optical path differences along a first axis while guaranteeing a formation of an interference pattern on a sensor, (ii) a movement unit for introducing a relative movement between the sample and the interferometer, along a second axis that is oriented to the first axis thereby virtually scanning the range of optical path differences, (iii) a processing circuit for receiving interference detection signals and reconstructing interferograms for different points of illumination on the sample. The measurement beam forms an elongated spot on the sample, having a longitudinal axis that is oriented to the first axis and the second axis.

The invention discloses a light off-axis structured light digital holographic microscopy super-resolution imaging method based on a Kramers-Kronig relation. In a light off-axis structured light digital holographic microscopy system, structural illumination patterns with different angle directions and phase shift amounts are loaded on an object light beam to acquire a structural illumination hologram, and an unloaded reference light beam is acquired to acquire a reference light intensity graph; the structure illumination hologram is combined with the reference light intensity graph to calculate complex amplitude by utilizing a KK relation, phase distortion of the complex amplitude is compensated to obtain distortion-removed complex amplitude, a frequency spectrum separation matrix is constructed by combining information during acquisition to perform frequency spectrum separation on high and low frequency components in the complex amplitude, and finally frequency spectrum synthesis is performed to realize super-resolution object light reconstruction. According to the invention, high resolution improvement can be realized, the interference problem of zero-order item frequency spectrum of the hologram under the light off-axis condition is effectively solved, the noise is obviously reduced, the imaging quality is improved, and the method has important application value in the fields of biological tissue observation, microstructure measurement and the like.