1001 results about "Beam splitting" patented technology

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 provides a covert communication method based on near-field broadband super-large-scale array beam splitting. Comprising the following steps: S1, according to an applied near-field covert communication scene, constructing a corresponding communication model by using a beam splitting effect in a broadband XL-MIMO system, carrying out beam training, and describing a received signal expression of the communication model; s2, constructing a signal detection model of a listener according to a near-field covert communication scene, and describing a detection error probability expression and a covert constraint expression; and step S3, the hidden transmission rate is maximized by optimizing the transmitting power and the subcarrier number of the transmitter. According to the method, the two-dimensional optimization problem related to the transmitting power and the subcarriers is converted into the one-dimensional optimization problem related to the discrete variable quantum carrier number, and the concealment rate of a legal receiver is maximized.

According to the switchable double-laser-head machining light path system and device, a three-dimensional galvanometer and a cutting head assembly are integrated into a machining head assembly, a light path switching mechanism is adopted, two dichroscopes are horizontally moved through a sliding table, selective light splitting is conducted on wavelength setting of the two dichroscopes, and therefore the machining precision of the two dichroscopes is improved. Rapid seamless switching and light path multiplexing between a three-dimensional galvanometer machining mode and a cutting head machining mode are achieved, it is ensured that the lens angle does not need to be adjusted again or light path alignment does not need to be conducted after light path switching, coaxial CCD monitoring is adopted, according to the wavelength setting characteristics of the two dichroscopes, the wavelength differentiation design is conducted on the first illumination light source and the second illumination light source, and therefore the machining efficiency is improved. According to the multi-axis moving platform, the same CCD camera is shared by two machining modes, high-precision real-time monitoring under the double machining modes is achieved, a closed-loop control basis is provided for the laser machining process, and meanwhile, the multi-axis moving platform is matched with the two rotary table assemblies, so that laser machining can be flexibly conducted on a curved-surface workpiece within a large-format range.

The embodiment of the invention provides an optical detection device which comprises an imaging assembly and a photoelectric detection device, and the imaging assembly is used for forming an image on an image plane of a to-be-detected area of a wafer. And the photoelectric detection device is used for receiving images and is arranged at the image plane. The photoelectric detection device comprises a light beam separation assembly and a sensor assembly, the light beam separation assembly is used for dividing a continuous first light signal in an image into multiple beams of second light signals, and the light beam separation assembly comprises a microlens array. The sensor assembly is used for receiving multiple beams of second optical signals, and each pixel unit of each sensor in the sensor assembly is used for receiving one beam of second optical signal in the multiple beams of second optical signals. The sensor assembly comprises a single-pixel sensor, and the single-pixel sensor corresponds to one micro lens in the micro lens array; and / or, the sensor assembly comprises a multi-pixel sensor, the multi-pixel sensor corresponds to a plurality of microlenses in the microlens array, and spatial segmentation is beneficial to improving the signal-to-noise ratio.

A kaleidoscopic laser beam projector (KLBP) system that employs a single moving structure to project patterns of sweeping laser beams with diverse sweep directions and emission apertures. The system comprises a collimated light source, a spinning mirror deflector (“spindle / flutter mirror”) at the center, and a stationary kaleidoscopic mirror containing multiple facet mirrors arranged in a concave fashion around the spindle mirror. As the spindle mirror rotates, it directs laser beams in a radially whirling movement toward the facet mirrors, which then subdivide these beams into multiple short strokes and redirect them outward in different directions. Various embodiments include configurations with diffractive optical elements (DOEs) for beam splitting, different kaleidoscopic mirror geometries (hexagonal, octagonal, etc.), and innovative flutter mirror mechanisms that create controlled angular variations during rotation. The system enables a “4×1” configuration that replaces traditional “4×4” systems requiring eight motors and multiple moving structures. The KLBP system offers significant advantages including mechanical simplicity, reduced size and weight, improved energy efficiency, enhanced reliability, cost-effectiveness, and modular configurability. The diverse beam incidence angles enable superior illumination of complex three-dimensional objects for applications in machine vision systems, precision metrology, gap and flushness inspection, and robot-assisted assembly of complex structures.

Disclosed in the present invention is a photometric stereo-based device for rapidly detecting surface features of an object, capable of rapidly acquiring a plurality of images meeting the requirements of a photometric stereo algorithm. The device comprises a light emitting assembly, an acquisition assembly located above the light emitting assembly, and a data processing module; the acquisition assembly comprises a light path system and a camera group; the light path system comprises: a beam splitting prism group used for splitting reflected light from the surface of an object into a plurality of beams of light and respectively outputting the plurality of beams of light in different preset directions to form images to be processed, and a plurality of bandpass filters correspondingly arranged on the output sides of the plurality of beams of light used for forming said images, wherein the central wavelengths of the bandpass filters are respectively configured to be different wavebands of the reflected light from the surface of the object; the camera group comprises a plurality of cameras which are arranged behind the bandpass filters in a one-to-one correspondence mode and acquire filtered light beams; and the data processing module receives image information sent by the cameras, and performs compensation and photometric stereo reconstruction on the image information, so as to obtain surface features of the object. Further disclosed is a method implemented on the basis of the device.

The invention relates to an integrated microcavity optical comb repetition frequency and optical frequency locking device and method, and belongs to the technical field of integrated microcavity optical combs. The locking device comprises a pumping module, a power amplification module, a phase modulation module, an electro-optic driving module, an acousto-optic modulation module, an acousto-optic driving module, a band-pass filtering module, a micro-ring resonant cavity and a beam splitting module; the device comprises a soliton detection module, a control module, a repetition frequency detection module, a first feedback control module, an acetylene frequency stabilized laser, a beat frequency module, an optical frequency beat frequency detection module and a second feedback control module. The locking device can achieve full frequency locking of the microcavity optical comb, has the advantages of being high in frequency stability, wide in servo bandwidth, simple and compact in structure, tight in locking, low in noise, high in reliability and low in cost, and can provide a powerful tool for the field of precision measurement.

The invention discloses a nanosecond particle velocity measurement method based on orthogonal line polarization beam splitting, and belongs to the technical field of particle image velocity measurement. The method comprises the following steps: providing two linear polarization state orthogonal double-pulse lasers, and respectively outputting S polarization pulse light beams and P polarization pulse light beams; the four pulse light beams are combined through the double-path laser beam combining mirror set and output to the sheet light mirror set, and a plane illumination jet flow field with the thickness smaller than or equal to 1 mm is formed; scattered light is separated according to a polarization state by using a polarization beam-splitting cubic prism, and particle images under S polarization and P polarization are respectively captured by two double-exposure cameras which are orthogonally arranged; five kinds of time sequence control are triggered through a multi-channel synchronous controller; processing the view field deviation of the two cameras by adopting a block polynomial alignment method; and calculating a particle velocity field based on a particle tracking velocity measurement algorithm. According to the invention, the polarization debugging error is reduced, the homogeneity error after beam combination is obviously reduced, the coincidence degree of the four beams of planar light is improved, and a high-precision universal alignment scheme is provided for the multi-camera PTV technology.

The invention provides an atmospheric pollutant traceability analysis method and system. According to the method, a form classification standard is established through particle shape features, and atmospheric particles are divided into naturally raised dust and industrial emission particle swarms. A dual-wavelength laser technology is adopted for natural flying dust, specifically, the first wavelength is matched with the inherent frequency of mineral crystals, amorphous scattering interference is blocked through polarization beam splitting, and a reflection signal sequence is extracted to generate a mineral migration path; and the second wavelength screens heavy metal scattering signals of the industrial particles, and a heavy metal diffusion track is constructed by utilizing spatial intensity gradient. And superposing the two paths and aerosol three-dimensional distribution data to generate a thermal distribution diagram, and when the space density exceeds a threshold value, calculating a migration path deviation value and a trajectory offset, dynamically distributing pollution source contribution weights, and outputting a pollution source analysis result. According to the invention, dynamic and accurate analysis of natural and industrial pollution sources is realized, and the regional pollution traceability and management and control strategy targeting are improved.

The invention provides a multispectral radiation temperature measurement method and system, and belongs to the field of signal acquisition and processing in an infrared radiation temperature measurement technology. The problems of poor inversion precision and applicability of multispectral radiation temperature measurement are solved. The multispectral radiation temperature measurement method comprises the following steps of: measuring radiation information of the surface of a to-be-measured target by using a multi-wavelength pyrometer; the beam splitting system obtains radiation information of different spectrum channels; photoelectric conversion: converting the optical signal into an electric signal; constructing a target equation and a constraint optimization condition according to the brightness temperature model; carrying out multispectral data processing by utilizing an improved multi-population mixed pigeon inspired optimization algorithm; and the final real temperature and emissivity values are obtained. The device is mainly used for multispectral radiation temperature measurement.

The invention discloses an optical waveguide and a preparation method thereof, relates to the technical field of optics, and is used for solving the problems of high processing difficulty, low yield and high cost of the existing array optical waveguide. The optical waveguide comprises a turning waveguide which is provided with a light incident surface, a first surface, a second surface and a plurality of first light splitting surfaces, the first surface and the second surface are arranged in parallel, the first light splitting surfaces are arranged in parallel, the included angle between the first light splitting surfaces and the first surface is smaller than 90 degrees, and the first light splitting surfaces enable light entering the turning waveguide from the light incident surface to be partially reflected; the reflected light is transmitted to the coupling-out waveguide; the coupling-out waveguide and the turning waveguide are spliced, so that light entering the coupling-out waveguide from the turning waveguide is emitted out of the coupling-out waveguide. The first beam splitting surface of the turning waveguide is not perpendicular to the first surface of the turning waveguide, compared with an existing array optical waveguide, the situation that the perpendicularity precision of the beam splitting surface and the surface of the optical waveguide needs to be strictly controlled in the machining process can be avoided, and therefore the machining difficulty can be lowered, the yield can be improved, and cost can be reduced.

The invention discloses a broadband full-Stokes polarization imaging device based on non-orthogonal four-channel polarization beam splitting, which comprises a dielectric substrate, a non-orthogonal polarization beam splitting metasurface and a focal plane detection array, and is characterized in that the non-orthogonal polarization beam splitting metasurface is composed of a plurality of sub-wavelength unit structures; the sub-wavelength unit structure is a single-layer anisotropic medium nano-column array and is configured to perform intrinsic-loss-free non-orthogonal four-channel beam splitting on incident light and form four spatially separated focuses on the same focal plane, and polarization states corresponding to the four channels form a regular tetrahedron measurement base on a Poincare sphere; therefore, full Stokes parameter measurement is completed by four pixels; the sub-wavelength unit structure forms a super-pixel unit, and the super-pixel unit is aligned and integrated with a focal plane detection array in a two-dimensional array form to form a compact polarization camera facing focal plane segmentation. The device is simple in structure, easy to integrate with the CMOS front end, small in device size, low in power consumption and high in mass production feasibility.

A receiving module, a detection device, a laser radar and a terminal are applied to the technical field of detection. Wherein the receiving module comprises a first light receiver, a second light receiver and a light splitting device, the light splitting device is used for splitting a light beam from a detection area into a first light beam and a second light beam, the first light beam is transmitted to the first light receiver, and the second light beam is transmitted to the second light receiver. The invention also correspondingly provides a detection device comprising the receiving module, a laser radar and a terminal. In the invention, the two groups of light receivers respectively receive the two paths of light beams divided by the light beams from the detection area, two groups of detection data with overlapped view fields can be obtained, the detection precision is obviously improved, the detection efficiency is ensured, the overall size of the detection device is not obviously influenced, and the heat dissipation pressure is not obviously increased.

The invention discloses a laser-assisted helium arc penetration fusion welding method, and belongs to the technical field of welding. The problems that according to an existing paraxial laser-electric arc composite structure, the welding track is difficult to control, the energy coupling efficiency is low due to laser energy loss, and weld joint partial melting and undercut defects are caused due to uneven distribution of a welding temperature field due to a generated asymmetric heat source are solved. The welding method comprises the steps of 1, pretreatment; 2, after being focused by a focus lens, the laser is divided into three laser beams through a spectroscope, then the three laser beams are converged again through a plurality of reflectors, three fan-shaped light spots are formed on the surface of the to-be-welded plate after convergence, and finally the focal plane position of the laser is adjusted to be located on the surface of the to-be-welded plate; 3, setting welding current and arc voltage; and fourthly, laser is used for assisting helium arc penetration fusion welding. The method is used for laser-assisted helium arc penetration fusion welding.

The invention discloses an all-fiber vortex interference system and a phase variation measurement method, belongs to the field of optical precision instrument design and test, and aims to realize ultrahigh-precision phase variation measurement by using an all-fiber structure. The vortex interference system comprises a light source module, an optical fiber beam splitting module, an optical fiber sensing module, an optical fiber mode conversion module, an optical fiber mode interference module and an imaging module in sequence along an optical path. The phase variation measurement method is a phase variation demodulation method based on angular Fourier transform, which is provided for the all-fiber vortex interference system. The interferometer provided by the invention does not need a complicated light path alignment step of a traditional interferometer, and the sensitivity of the all-fiber vortex interferometer is further improved.

The present disclosure describes a turntable parallel scanning confocal microscope illumination light path, the illumination light path comprising a sleeve assembly having a light source and a field diaphragm, a lens barrel assembly having a collector lens, a beam splitting chamber having a turntable, a tube lens and a microscope objective, the light source being configured to form a first parallel beam entering the lens barrel assembly via the field diaphragm; the light source is imaged on the focal plane of the light collecting mirror; the turntable is configured to receive a second parallel light beam emitted from the tube lens, the second parallel light beam is configured to form a preset image on the turntable, the turntable is configured to receive a first parallel light beam emitted into the light splitting chamber through the lens barrel assembly, and the first parallel light beam is configured to form a light spot covering a small hole surface of the turntable on the turntable; the microscope objective is configured to be installed at the position of an image of the light source which is formed by the light beam emitted from the tube mirror and meets the preset requirement. According to the invention, the illumination light path of the turntable parallel scanning confocal microscope, which is simple and convenient to operate and can be conveniently and accurately assembled and adjusted, can be provided.

An atomic magnetometer, an atomic magnetometer measurement system, and a magnetic field measurement method. The atomic magnetometer comprises a laser (1), a probe (2), a magnetic field generation unit (3), and a magnetic field compensation unit (4); the probe (2) is connected to the laser (1) by means of a polarization-maintaining collimation optical fiber (5), and light emitted by the laser (1) is used as pump light; the probe (2) is used for performing beam splitting on the pump light and in a gas chamber, forming two beams of light that are perpendicular to each other and do not intersect with each other, so as to respectively detect the two beams of light to obtain a first detection signal and a second detection signal; the magnetic field generation unit (3) is used for generating a magnetic field signal at the gas chamber on the basis of modulation signals in three directions; the magnetic field compensation unit (4) is used for compensating, on the basis of the modulation signals in the three directions, the first detection signal and the second detection signal, magnetic fields to be measured in the three directions to zero, and performing measurement to obtain said magnetic fields. The atomic magnetometer, the atomic magnetometer measurement system, and the magnetic field measurement method can enlarge a bandwidth range for measurement.

The invention provides a preparation method of a multilayer film plane window reflector film system, which adopts a vacuum evaporation method, the structure of the film system is G (Hf-SiO2) n (A), a reflecting film takes HfO2 as a high-refractive-index material and takes SiO2 as a low-refractive-index material, and the HfO2 layer is completed by evaporating Hf deposition in an oxygen-containing vacuum environment. According to the method disclosed by the invention, the TOLLING value parameters are captured for multiple times in stages in the coating process, so that the performance of the prepared plane window reflecting mirror can be remarkably improved, the plane window reflecting mirror is closer to a design value, and the method has important application in preparation of a high-performance beam splitting film.

The invention discloses an optical computing array based on micro-ring resonators without a free spectral range, which comprises an on-chip wavelength division multiplexing beam splitting array, an on-chip intensity modulation array, two groups of on-chip wavelength division multiplexing beam combining arrays and an on-chip balance detector, the on-chip wavelength division multiplexing beam splitting array and the on-chip wavelength division multiplexing beam combining array are respectively composed of a group of multiple FSR-free MRRs which share the same bus optical waveguide, each resonator corresponds to an independent wavelength channel, and the on-chip intensity modulator array is composed of a plurality of groups of on-chip MZI modulator arrays. According to the optical calculation array implementation method, independent control and coding calculation of different wavelength channels in a broadband wavelength range are realized by utilizing the single harmonic peak characteristic of the FSR-free MRR array and the wide-spectrum intensity modulation function of the MZI unit, the limitation of a free spectrum range on the optical calculation wavelength channel is eliminated, the higher wavelength parallelism is achieved, and the optical calculation array implementation method has the advantages of being simple in structure and convenient to implement. And therefore, the calculation scale is remarkably improved.

The invention discloses a multi-target three-dimensional measurement device and method based on a double-optical-comb femtosecond laser radar, and relates to the field of femtosecond laser measurement, and the device comprises a double-optical-comb laser source, a single-detector time-sharing switching receiving module, a beam splitting and optical switch module and a scanning galvanometer module which are connected in sequence, and further comprises a single-detector time-sharing switching receiving module, a beam splitting and optical switch module and a scanning galvanometer module which are connected in sequence. The signal control processing module is connected with the single-detector time-sharing switching receiving module, generates a reference pulse signal and a target pulse signal based on the above modules, carries out distance calculation according to the reference pulse signal and the target pulse signal of each target light path, determines a to-be-measured distance of a target object, and sends the to-be-measured distance to the single-detector time-sharing switching receiving module; and performing three-dimensional reconstruction on the target object according to the to-be-measured distance of the target object and the angle information of the scanning galvanometer, and generating a point cloud or a three-dimensional profile diagram of the target object in the current scene, so that the system implementation difficulty and the measurement error can be reduced.

The invention belongs to the technical field of laser wire stripping machines, and particularly discloses a deflection type double-head laser wire stripping machine which comprises a first machine frame and a second machine frame, the second machine frame is arranged on one side of the first machine frame, a cutting mechanism is arranged on the inner side of the first machine frame, and a placing table is fixedly connected to the top of the second machine frame; the cutting assembly is arranged, the double-laser-source modules adopt beam splitter prisms or double independent optical fiber lasers, CO2 laser and optical fiber double-waveband combination is supported, different insulation and metal materials are adapted, a driving motor is used for driving a rotating shaft to drive a connecting rod to rotate, and the two double-laser-source modules are driven to rotate by + / -30 degrees through mechanical deflection to reduce cutting dead angles. And the CCD measuring module is used for detecting the outer diameter of the wire rod and feeding back the detection result to a console, so that a worker can conveniently adjust the rotating angle of the double-laser-source modules, the cutting effect is improved, and the machining efficiency can be effectively improved through synchronous operation of the two double-laser-source modules.

The invention relates to the technical field of precision and ultra-precision machining, and discloses a CO2 full-laser machining device and method for a fused quartz micro convex lens array. The three-axis motion platform is arranged on the supporting platform; the pulse CO2 laser is used for generating a processing laser beam; the light beam transmission system sequentially comprises a light beam combining module, a light beam adjusting module, a light splitting module, a light beam guiding module, a scanning galvanometer and a focusing field lens along a laser beam path; the main light beam is guided to the scanning galvanometer through the light beam guiding module and is emitted to a fused quartz workpiece after being focused through the focusing field lens; the contour detection unit is used for taking morphology data of the micro-lens array in situ; the temperature monitoring unit is used for measuring the temperature of the processing area; the control unit is connected with the three-axis motion platform, the contour detection unit, the temperature monitoring unit and the pulse CO2 laser, and is used for adjusting the laser power and the displacement of the three-axis motion platform according to detection data; the device has the characteristics of high efficiency, high precision, non-contact processing and small heat influence.

The invention relates to a wind measurement laser radar system, which comprises a first light source assembly for emitting first signal light and a second light source for emitting multimode pump laser, the acousto-optic device is used for performing pulse and frequency shift modulation on the first signal light to obtain second signal light; the first optical fiber is a double-cladding erbium-ytterbium co-doped optical fiber and is used for amplifying the second signal light to obtain third signal light; the polarization reflection device filters amplified spontaneous emission light in the third signal light to obtain fourth signal light; the first optical fiber further amplifies the fourth signal light again to obtain fifth signal light; the acousto-optic device performs pulse and frequency shift modulation on the fifth signal light again to obtain sixth signal light; the time division switching device controls the deflection module to deflect the sixth signal light, so that the sixth signal light is split by the beam splitting module at different time to obtain seventh signal light, the seventh signal light is emitted through different ports, the power of the two-way amplifier can be further improved, and the detection distance of the wind measurement radar is increased.

The invention relates to the field of optical display and material engineering, in particular to a silica gel integrated optical film with a 3D light splitting function and a manufacturing method of the silica gel integrated optical film. A silica gel integrated optical film with a 3D light splitting function comprises a transparent optical base material and a microstructure layer, and the microstructure layer is combined on the surface of the transparent optical base material in an integrated forming mode. And the microstructure layer is an anhydrous silica gel-resin composite material obtained by combining organic silica gel with low refractive index and resin with high refractive index through an anhydrous chemical reaction system. The optical film obtained in the invention has excellent interface bonding stability and long-term reliability, the overall thickness of the optical film is small, the optical loss is reduced, the light transmittance is higher, and the overall transmittance can reach 93% or above. And the manufacturing process integration degree and the mold repeated utilization rate are high, the industrial batch production requirement can be met, and the excellent industrial application prospect is achieved.

The invention discloses a vortex beam orbital angular momentum detector based on surface plasmon and a detection method, and belongs to the field of micro-nano photonics and photoelectric detection. The detector is based on a plane photoelectric detector of a metal-semiconductor-metal type, a vortex light field beam splitting structure is arranged on a metal electrode on one side of the detector or between two metal electrodes, the vortex light field beam splitting structure comprises an incident coupling grating, an incident light field carrying different orbital angular momentums can be split into plasmons in different directions, and the plasmons in different directions can be split into a vortex light field. The single detector resolution of the orbital angular momentum of the vortex beam is realized through the direction and propagation loss difference of plasmons. The detector is compatible with an existing semiconductor technology, the structure is simple, vortex light beams carrying high-order orbital angular momentum can be detected, and the rotation direction of a vortex light field can be detected.

A water-mist-penetrating three-wavelength temperature measurement device and method for a high-temperature environment, the device including a housing, a three-waveband beam splitting detection module and a computing unit, the housing provided with an optical aperture, the three-waveband beam splitting detection module arranged in the housing, and including a trichroic prism, three radiation detection assemblies, the trichroic prism able to receive the light signals entering via the optical aperture, and emit radiation signals having different wavelength bands through three emission faces, respectively; the three radiation detection assemblies able to receive radiation signals having different wavelength bands emitted from corresponding emission faces, and convert them into electrical signals, respectively; the computing unit able to receive the electrical signals, and perform calculation and analysis to determine a temperature value of a target to be measured; the method including: temperature measurement data acquisition, data fusion, parameter tuning, and model application.

The invention discloses an industrial robot end effector for ultrafast laser processing. The industrial robot end effector comprises a 3D galvanometer module, a normal posture adjusting module, an ultrafast laser transmission module, a reflector module, a polarization beam splitting module, a mounting frame and a visual positioning module. Wherein the ultrafast laser transmission module, the reflector module, the polarization beam splitting module and the 3D galvanometer module are connected with one another and are finally mounted and fixed on the mounting frame; and the normal posture adjusting module and the visual positioning module are directly mounted and fixed on the mounting frame respectively. The end effector can be integrated with an industrial robot system, the ultrafast laser machinable structure scale is expanded through flexibility of the industrial robot, industrial robot end precision positioning is achieved through multi-sensor fusion of the end effector, the machining precision in a large-size range is further improved, and the machining precision is improved. Therefore, high-precision and low-damage machining of the satellite large composite material structure is achieved.

The embodiment of the invention provides an eyepiece system and optical equipment. The eyepiece system comprises a first optical assembly and a second optical assembly which are arranged along the same optical axis. The first optical assembly is located on the eye side, is of a folded light path structure and comprises at least two lenses, a first composite optical film material and a light splitting element, the first composite optical film material comprises a first phase retarder and a polarization reflection element which are arranged in a stacked mode, and the first phase retarder is located between the light splitting element and the polarization reflection element; the second optical assembly is located on the display side, is of a direct light path structure and comprises at least one transmission lens. The eyepiece satisfies the following relational expression: 25 < = (D1 * phi 1-D2 * phi 2) / phi < = 50; wherein D1 is the maximum optical aperture in the first optical assembly, phi 1 is the focal power of the first optical assembly, D2 is the maximum optical aperture in the second optical assembly, phi 2 is the focal power of the second optical assembly, and phi is the focal power of the whole eyepiece system.

The invention discloses an ultra-wide thin-wall tunnel roof deformation monitoring device based on laser ranging, and relates to the technical field of laser measurement, the ultra-wide thin-wall tunnel roof deformation monitoring device comprises an industrial camera and a mounting seat, a laser is fixedly mounted on the mounting seat, a mounting bracket is mounted at the bottom of the mounting seat, and a protective shell is fixedly mounted on the mounting seat. A light beam collimator is fixedly installed on the laser device, and a beam splitting assembly is fixedly installed in the protective shell and used for equally dividing a light source emitted by the laser device into two laser beams. The tunnel section deformation monitoring method has the advantages that high-precision and high-efficiency deformation monitoring can be performed on the tunnel section, the problems of time desynchrony and optical distortion existing in a traditional method are effectively solved, and meanwhile, the adaptability and data reliability in a severe environment are remarkably improved; and reliable technical means and equipment support are provided for structural health assessment of the ultra-wide thin-wall tunnel top arch.

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.