408 results about "Gaussian beam" patented technology

The invention provides a thermal wave imaging detection method based on nonlinear frequency modulation microwave excitation induction, and the method comprises the steps: constructing a composite excitation module of Gaussian beam and dynamic phase compensation, decomposing high-frequency / low-frequency sub-pulses for alternate emission, synchronously collecting infrared non-uniform sampling and microwave polarization diversity data, and carrying out the detection of the thermal wave imaging. And through feature fusion of a time domain CNN and a frequency domain graph neural network, propagation parameters are iteratively corrected in combination with a thermal diffusion equation model, and defect and deep structure detection is realized. According to the method, the composite excitation structure is combined with high-frequency / low-frequency sub-pulse alternate emission, the micro-defect detection resolution and the deep structure penetrating capacity are remarkably improved, the feature robustness is enhanced through multi-modal data acquisition and cross-modal neural network fusion, detection depth self-adaptive optimization is achieved through a depth compensation model and Kalman filtering, and the detection precision is improved. The parameter precision is improved with the assistance of a terahertz spectrum coupling matrix and Landweber iterative inversion, and finally an advanced detection system integrating efficient excitation, multi-dimensional perception and intelligent analysis is formed.

The invention relates to the technical field of laser processing devices, in particular to a device and method for achieving three-dimensional isotropic processing through a rotating slit. The three-dimensional motion platform is used for placing and driving a transparent material to be processed; the slit is provided with a driver to enable the slit to rotate, laser beams emitted by the laser emitting device are subjected to light path adjustment and then pass through the center of the slit to form elliptical light beams, and the elliptical light beams are focused by an objective lens and then are transmitted to the laser receiving device. The three-dimensional isotropic processing of the transparent material is realized by adjusting the rotating speed of the slit and the direct writing speed of the three-dimensional motion platform; according to the invention, the rotatable slit is arranged, a circular Gaussian beam emitted by the laser emitting device passes through the slit to form an elliptical beam, the elliptical beam is rapidly rotated by rapidly rotating the slit, and after the elliptical beam is focused by the objective lens, spatial three-dimensional spherical symmetrical focal field distribution can be obtained in the transparent material, so that three-dimensional isotropic processing is realized.

The invention discloses a laser processing device, a silicon carbide crystal ingot cutting method and a laser processing system. The laser processing device comprises a laser used for emitting Gaussian beams with preset laser parameters; the beam shaping element is used for shaping the Gaussian beam into a linear beam; and the scanning mechanism is used for focusing the linear light beam and cutting the silicon carbide crystal ingot by utilizing the focused linear light beam according to a preset cutting path and a preset cutting speed. Compared with the focused Gaussian beam, the focused linear beam has a small spot size in the direction of the optical axis, which means that the action depth of the focused linear beam in the silicon carbide crystal ingot is shallower, so that the length of the growth area of the microcracks generated in the direction of the optical axis in the machining process is reduced, and the machining precision is improved. And therefore, the roughness generated on the surface of the silicon carbide wafer is reduced, and the quality of the silicon carbide wafer is improved.

The invention discloses a light spot shaping device based on wave plate polarization conversion and a use method, and relates to the technical field of laser processing, the device divides random polarized light into S / P light through a first polarization beam splitter (PBS), converts the S light into P light through a first 1 / 2 wave plate, modulates the S light through a conventional silicon-based liquid crystal spatial light modulator (LCoS SLM), and converts the P light into the S light through a second 1 / 2 wave plate. And the beams are combined by the second PBS. The method comprises the steps of light splitting, polarization conversion, phase modulation, beam combining, beam expanding and focusing and the like. The double 1 / 2 wave plates are combined with the conventional PBS, the laser energy utilization rate is higher than 85%, commercial SLM equipment is adapted, the machining efficiency of the shaped annular light spots is remarkably improved compared with that of Gaussian beams, the method is suitable for laser welding and metal 3D printing, and the problems of energy waste and high cost are solved.

This system and method of for providing a tunable orbital angular momentum system for providing higher order Bessel beams comprising: an acousto-optical deflector configured to receive an input beam, deflect a first portion of the input beam a first deflection angle relative to an axis of propagation and along an optical axis and deflect a second portion of the input beam a second deflection angle relative to the optical axis; a line generator disposed along the optical angle for receiving the first portion and the second portion of the input beam and provide an elliptical Gaussian mean; a log-polar optics assembly disposed along the optical angle for receiving the elliptical Gaussian beam and wrapping the elliptical Gaussian beam with an asymmetric ring; and, a Fourier lens configured to receive the wrapped elliptical Gaussian beam.

A metasurface lens (2) for shaping a Gaussian beam into a collimated uniform beam, and a design method. The metasurface lens (2) comprises a dielectric substrate layer (203) and a metasurface microstructure. The metasurface microstructure comprises a first metasurface (201) and a second metasurface (202) which are respectively distributed on two sides of the dielectric substrate layer (203), and the first metasurface and the second metasurface each are formed by periodically arranging a plurality of columnar microstructure units. The distribution mode of the columnar microstructure units of the metasurface lens (2) is optimally designed on the basis of irradiance distribution of the Gaussian beam and a target collimated uniform beam, so that emergent beams are parallel to an optical axis and are uniformly distributed in a target range. The metasurface lens (2) implements laser shaping to obtain a target beam; and additionally, the structure is simple, the application range is wide, and the present invention is suitable for laser shaping of various lasers.

The invention relates to a focusing regulation and control method and device based on a vortex structure light field penetrating through a large-scale scattering medium, and the method specifically comprises the steps: generating a collimated and expanded laser beam through a laser, carrying out the phase modulation of the laser beam through a spatial light modulator, and collecting a transmission speckle image related to the scattering medium through the combination of an sCMOS camera; and obtaining an optimal phase according to a focusing index quantity fed back by a focusing area by combining a genetic neural network algorithm with the vortex structure light field, and realizing speckle focusing through multiple iterations. Compared with the prior art, a vortex structure light field method is introduced to improve the feedback focusing regulation and control effect, the problem that a traditional feedback modulation algorithm cannot focus a large-scale scattering medium is solved, and the focusing intensity is remarkably superior to that of a lens focusing method and a wavefront shaping focusing method based on Gaussian beams.

The invention relates to the field of ultra-precision polishing, in particular to an in-situ laser polishing system for a diamond turning metal surface. Comprising a turning tool servo shaft, a laser polishing assembly and a controller, a laser emitting part is arranged on the turning tool servo shaft, and the controller is used for controlling polishing laser emitted by the laser emitting part to move and scan on the surface of a turned workpiece in the direction perpendicular to the turning path. The distance between two adjacent scanning paths is smaller than the diameter of the Gaussian beam. According to the invention, the laser polishing system is integrated on the ultra-precision machine tool, so that the turning and polishing processes of the workpiece can be completed under the same clamping, and secondary clamping and repositioning, introduced scratches and clamping errors are avoided. And meanwhile, the surface of the workpiece is heated through the out-of-focus light spots, so that the material in the area is in a flowable state after being heated, and under the action of gravity or self-tension, the material at the high position moves to the low position, so that the self-leveling effect is achieved, and the surface roughness is 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.

A design method for a metalens, a metalens, a shaping and beam-combination device and a display device are provided, when Gaussian beams passes through the metalens, the Gaussian beams are shaped into a plurality of flat-topped beams that project to a target position on a target plane. The method includes: determining an incident parameter, and the incident parameter includes wavelengths and radius of the plurality of Gaussian beams; determining an outgoing parameter, and the outgoing parameter includes a width of flat-topped beams; setting metalens portions on the metalens and determining a position of each metalens portion; the metalens portions and the Gaussian beams are one-to-one correspondence, calculating a modulation phase distribution according to the incident parameter, and the outgoing parameter and the position of each metalens portion; arranging unit cells on the metalens portions according to the modulation phase distribution, and obtaining the metalens.

The invention is suitable for the technical field of laser processing, and provides laser processing equipment. The laser processing equipment comprises a laser device used for emitting a laser beam; the light path switching system is used for deflecting the laser beam to a flat-topped light path or a Gaussian light path, the laser beam is output in a flat-topped light beam mode through the flat-topped light path, and the laser beam is output in a Gaussian light beam mode through the Gaussian light path; the processing head is used for deflecting the emergent direction of the flat-topped light beam output by the flat-topped light path or the Gaussian light beam output by the Gaussian light path and guiding the flat-topped light beam or the Gaussian light beam to a preset processing position; and the controller is coupled to the light path switching system through communication and is used for controlling the light path switching system to switch the laser beam between the flat-topped light path and the Gaussian light path according to processing requirements. In the embodiment of the invention, the laser processing equipment can be quickly switched among the laser beams in different modes, so that the processing efficiency can be improved.

The invention belongs to the technical field of radiation effect and radiation hardening of semiconductor devices and integrated circuits, and particularly relates to a single event effect laser simulation system based on Bessel beam shaping. A Bessel beam shaping and focusing module based on an axon lens is introduced and composed of the axon lens and two lenses, namely a single lens and a focusing lens, a Gaussian beam of an incident beam is shaped into a quasi-Bessel beam, and the quasi-Bessel beam is utilized to irradiate a semiconductor device to be detected. The axial distribution of the light beam is kept unchanged in a range of hundreds of microns, and the focusing breaking through the diffraction limit is realized in the radial distribution, so that the effect closer to the heavy ion charge deposition track is generated. The technology can solve the problem that a multilayer structure device, a thick sensitive region device and a wide forbidden band device are difficult to test through traditional laser simulation, and has important practical value for promoting laser simulation of the single event effect.

The invention discloses a non-diffraction laser communication terminal based on Bessel beams. The terminal comprises a beacon transmitting module, an optical antenna module, a beacon receiving module, a signal transmitting module, a signal receiving module and a light splitting module. The beacon transmitting module and the signal transmitting module respectively convert the Gaussian beam into a Bessel beam through an axicon, and the Bessel beam is output through a collimating lens; a primary mirror and a secondary mirror of the optical antenna module are mounted in an off-axis manner, so that light beams are shrunk and expanded; the light splitting module completes light path switching and light splitting through a fast reflecting mirror, a 1 / 4 wave plate, a dichroscope and a polarizing beam splitter; the beacon receiving module obtains beacon light position information through a CMOS detector, and the signal receiving module receives signal light through an APD detector. The non-diffraction characteristic of the Bessel beam is utilized, and the off-axis optical antenna and the polarization beam splitting design are combined, so that high-precision and low-loss laser communication is realized.

The embodiment of the invention discloses an etching method, an etching device and a perovskite assembly. The etching method is used for etching a top electrode of a battery to be etched. The etching method comprises the following steps: shaping a Gaussian beam into a square flat-topped beam; adjusting a preset focusing position of the square flat-topped light beam; controlling the to-be-etched battery and the square flat-topped light beam to reach relative positions, and controlling the to-be-etched battery and the square flat-topped light beam to move relatively along a first direction and / or a second direction; and etching the to-be-etched cell according to the preset focusing position, so that the depth of an etching groove formed by etching is greater than or equal to the thickness of the top electrode and less than the sum of the thickness of the top electrode and the thickness of the perovskite functional layer. According to the technical scheme provided by the embodiment of the invention, the Gaussian beam is converted into the square flat-topped beam, and the focal depth lower edge of the generated square flat-topped beam only acts on the top electrode on the surface of the film layer, so that the actual use power is reduced, the influence of laser on other functional layers in the perovskite component can be avoided, and the performance of the perovskite component is improved.

The invention discloses a multi-laser-area printing device capable of regulating and controlling defects. The multi-laser-area printing device comprises a forming mechanism, a laser emitting mechanism, a defect detecting mechanism and a laser printing regulating and controlling mechanism. The additive laser emission mechanism is used for generating a Gaussian beam or a flat-topped beam; the subtractive laser emitting mechanism is used for generating subtractive laser; the laser printing regulation and control mechanism is used for focusing the generated Gaussian beam or flat-topped beam on a forming substrate of the forming mechanism for printing or focusing the generated subtractive laser on the forming substrate for defect removal; the defect detection mechanism is used for detecting whether the printed current layer on the forming substrate has defects or not; the control mechanism is used for controlling the forming mechanism, the laser emission mechanism, the defect detection mechanism and the laser printing regulation and control mechanism to conduct coordinated actions, and printing of the part to be formed and defect removal are completed. The printing speed is effectively increased, the printing precision is guaranteed, and the machining reliability and the surface forming quality are greatly improved.

The invention provides an efficient glass substrate through hole preparation device and a structure for generating multiple Bessel beams, which are applied to the technical field of laser processing, and the method comprises the following steps: splitting Gaussian beams generated by a laser through a beam splitting element to obtain multiple Gaussian beams; according to the method, the multiple Gaussian beams are obtained, then the multiple Gaussian beams are subjected to shaping treatment through the optical shaping element, the multiple Bessel beams are obtained, and compared with a mode that a single Bessel beam is used for preparing the glass substrate through hole, the multiple Bessel beams can be generated, so that the preparation efficiency can be improved; besides, any sub-beam of the multiple Bessel beams used for preparing the glass substrate through hole is directly converted from a Gaussian beam, and due to the fact that the Gaussian beam has the characteristic of symmetry, the formed Bessel beam used for preparing the glass substrate through hole is rounder in light spot formed by focusing, and therefore the high-roundness glass substrate through hole can be prepared.

The invention relates to the technical field of optical control, in particular to a micro-nano particle optical control method and device based on circularly polarized light. The invention aims to solve the problem of insufficient flexibility of optical control. The optical control method comprises the following steps: pre-processing micro-nano particles to be controlled; the initial Gaussian beam is processed into a circular polarization tube type beam through a beam shaping module, a light guiding module and a polarization regulation and control module, and the micro-nano particles are irradiated from the position above the gas-liquid interface according to a preset mode; by adjusting the polarization regulation and control module and the light guide module, the motion direction, the motion speed and the stop position of the micro-nano particles are optically controlled. The optical control device comprises a control platform module, a laser emitting module, a light beam shaping module, a light guiding module, a polarization regulation and control module and an imaging monitoring module.

The invention relates to the technical field of optical application, and discloses a method for shaping Gaussian light into a linear light beam based on an analytical method, which comprises the following steps: S1, establishing a mathematical model of an input Gaussian light beam and an output linear light beam, and determining a relationship between a shape parameter of the output linear light beam and Uout (x, y), S2, deducing a phase compensation function, the method comprises the following steps: S1, deducing a phase compensation function which needs to be loaded by an SLM by means of an analytical method, S3, loading the phase function to the SLM, and checking the accuracy of phase modulation by using the characteristic that the SLM modulates a light beam phase, and S4, shaping and verifying the light beam. According to the method, the phase pattern can be accurately calculated according to the specific light beam parameters and the target shape, and the method has better universality. Corresponding phase patterns can be calculated through an analytical method for Gaussian beams with different wavelengths and waist radiuses or linear beams with different widths, lengths and light intensity distribution requirements, and the phase patterns are loaded to the SLM, so that efficient and accurate beam shaping is realized.

The invention discloses a light spot adjustable optical system, a diffraction optical module and laser processing equipment, and relates to the technical field of precision processing. The optical system comprises a laser, a beam expander, a diffractive optical module and a focusing module which are sequentially arranged in the light path direction, the diffractive optical module comprises at least one diffractive optical element, and the diffractive optical element is manufactured based on a geometric phase liquid crystal polymer birefringent material. The diffractive optical module is used for regulating and controlling light spot characteristic parameters corresponding to a Gaussian beam, the Gaussian beam is emitted by the laser and enters the diffractive optical module after being expanded and collimated by the beam expander, and the light spot characteristic parameters comprise a light spot distribution position and light spot energy intensity. By the adoption of the optical system, laser energy distribution can be optimized, splashing is effectively restrained, and the welding quality and the processing efficiency are improved.

The utility model discloses a light feeding instrument to solve the problem that retina light damage is possibly caused after long-term use in the prior art, and meanwhile, the treatment effect is also improved. Compared with the prior art in which only parameters such as red light source power and emergent light beam size are concerned, the utility model focuses on the important index of irradiance (power density), emergent light is a collimated Gaussian beam and the optical characteristics of eyes (a human eye refraction system is equivalent to a convex lens with a focal length of 17.2 mm). An optical component diffuser is additionally arranged at the position close to the cornea of a user, so that a collimated Gaussian beam is converted into diffused light to enter the eyes of the user, and diffused light spots are formed on the retina, the treatment area is sufficient, energy distribution is uniform, it is ensured that the irradiance is at the expected safety magnitude, and meanwhile the actual treatment effect is ensured.

This invention presents a frequency-domain fluorescence lifetime imaging system, enhancing capabilities with a spatial beam attenuator and pinhole beam splitter. The spatial beam attenuator reshapes any beam into a circular Gaussian beam profile, being compact, cost-effective, with low loss and back reflection. Using digital printing technology, a thin optical film is deposited onto an optical substrate for precise local attenuation of the beam in either transmission or reflection mode. The pinhole beam splitter consists of an optical beam splitter with an active region the size of a pinhole, positioned near the beam's focus, which directs focused light into two paths based on acceptance or rejection by the pinhole. This configuration allows for two detectors to collect photons from both paths concurrently, facilitating dual-mode imaging. Consequently, the system can generate both confocal and conventional non-confocal laser scanning fluorescence lifetime images of the sample at the same time.

The invention provides an unmanned aerial vehicle wireless energy supply method and system based on multiband laser and intelligent tracking and pointing, and relates to the technical field of unmanned aerial vehicle wireless energy transmission. The method comprises the following steps: dynamically selecting a 1064nm or 1550nm laser band according to a real-time distance between the unmanned aerial vehicle and a transmitting end, and shaping a Gaussian beam into a flat-topped beam through a variable-focus collimating lens group; a tracking and aiming mode combining coarse tracking and fine tracking is adopted, in fine tracking, through an infrared beacon and a CCD image servo closed loop, observation noise covariance is dynamically estimated in combination with a Transform-AKF fusion algorithm, and process noise covariance is adjusted in a self-adaptive mode; the offset of the reflection light spots is detected through the reverse reflector to realize jitter compensation; fusing the fine tracking angle and the jitter compensation amount to generate a final aiming instruction; meanwhile, according to energy feedback data and tracking errors of a receiving end, laser output power is adjusted in a self-adaptive mode through a PID algorithm. According to the invention, long-distance, high-precision and self-adaptive unmanned aerial vehicle wireless energy transmission is realized.

The invention discloses a laser cladding method for a wind power sliding bearing, and particularly relates to the technical field of laser cladding. The method comprises the following steps that a wind power gear box pin shaft is fixed to a positioner and adjusted to be axially horizontal, and a laser cladding head is positioned to the position above the central axis of the pin shaft through an industrial robot; laser cladding is conducted in a synchronous powder feeding mode, a cladding head is controlled to horizontally move in the axial direction, meanwhile, a positioner drives a pin shaft to rotate, and a spiral coating is formed on the surface of the pin shaft in a cladding mode; and after single-layer full covering is completed every time, the cladding head is moved reversely to conduct next-layer cladding, coating thickness accumulation is achieved through direction alternation and interlayer superposition, and the technology is terminated till the preset value is reached. By the adoption of the technical scheme, the problem that in the prior art, a sliding bearing is insufficient in friction and wear performance is solved, a flat-topped beam is adopted to replace a traditional Gaussian beam for cladding, the particle size of powder is refined, and the prepared coating has the advantages of being few in crack defect and good in friction and wear performance.

The invention belongs to the technical field of laser, and particularly discloses a beam shaping system and method based on prism pair orthogonality and cascade, and the system comprises a single-mode fiber, an aspherical lens, a first prism pair, a first parallel plate, a second prism pair and a second parallel plate which are sequentially arranged along the direction of an optical axis. A Gaussian beam emitted by a single-mode optical fiber is collimated by an aspherical lens to form a parallel beam, the beam is expanded or compressed in the X direction by a first prism pair, the beam is expanded in the Y direction by a second prism pair, and two inclined parallel plates are respectively used for compensating the beam offset in the X / Y direction; according to the invention, the circular Gaussian beam emitted by the single-mode fiber can be shaped, a large strip-shaped collimation light spot with an adjustable length-width ratio from 4: 1 to 20: 1 and a long axis size of 30mm can be realized, and the central positions of the input and output beams in the cross section are ensured to be unchanged.

The invention belongs to the technical field of optical communication safety, and aims to solve the problem that the robustness of chaotic laser in a turbulent environment is poor and the chaotic laser is seriously limited in long-distance free space optical communication. The invention provides an anti-turbulence chaotic Bessel Gaussian beam generation device and method, and the method comprises the following steps: laser is collimated through a first plano-convex lens, passes through an adjustable continuous light attenuation mirror and a dielectric film reflector, then returns to the interior of a laser, and generates a chaotic Gaussian beam based on the disturbance of a light field; a chaotic Gaussian beam is emitted from a first non-polarization beam splitter, and the polarization state of the beam is adjusted through a half-wave plate and a linear polarizer, so that the working direction of the beam is the same as that of a reflective pure-phase spatial light modulator; and the beam is expanded by the second plano-convex lens and the third plano-convex lens and is transmitted to the reflective pure-phase spatial light modulator to obtain an l-order chaotic Bessel-Gaussian beam. According to the invention, the chaotic laser and the Bessel beam are combined to cope with a complex space optical communication environment.

The invention discloses an automatic focusing optical system and visual detection equipment with the same, and relates to the technical field of optical detection. The system comprises a focusing module, the focusing module comprises a light source, a collimation unit and a beam expanding unit, the collimation unit is used for collimating a Gaussian beam emitted by the light source into a flat-topped beam, the beam expanding unit comprises a micro-lens array and a convex lens which are sequentially distributed in the emergent direction of the flat-topped beam, and a shielding piece is arranged on the light incident side of the convex lens; the front surface of the micro-lens array is used for dividing the flat-topped light beam into a plurality of sub-light beams, the rear surface of the micro-lens array is used for mutually superposing the focused sub-light beams to form a homogenized light beam, and the convex lens is used for expanding the homogenized light beam into parallel light beams; and the detection module comprises an objective table and an imaging unit, the objective table is used for bearing the to-be-detected sample, and the imaging unit is used for imaging and focusing through the parallel light beams reflected by the to-be-detected sample. By adopting the system provided by the invention, the uniformity of linear light spots can be obviously improved, and burrs and noise are eliminated.

The invention belongs to the technical field of photoetching detection, and particularly discloses a photoetching defect detection method and system based on orbital angular momentum. According to the method, the OAM light beam is used for replacing the Gaussian light beam for illumination, the defect position is determined by analyzing the far-field asymmetric signal generated along the scanning path, and the far-field asymmetric signal caused by the defect under the irradiation of the OAM light beam is more obvious, so that the signal-to-noise ratio can be increased by 5.57 times at most, and the sensitivity of defect detection is remarkably improved; according to the method, OAM light beam illumination is used, the scanning step length is the integral multiple of the minimum period of the sample pattern in the scanning direction, the left-right asymmetric information and the up-down asymmetric information of the specific scanning points are synthesized, the coordinate position of the defect is determined, more available information is achieved, and the false detection rate is reduced. Diffraction processing is carried out on the diffraction images corresponding to the adjacent scanning points of the defect-containing sample, diffraction image difference between the defect-containing sample and a defect-free sample is not needed, the position error is small in the actual implementation process, symmetry is not needed for the sample pattern, and the applicability is higher.

A laser scribing method for perovskite thin-film solar cells is provided, in which a linearly polarized Gaussian beam is emitted by a laser, and converted into a circularly polarized beam through a quarter-wave plate. The circularly polarized beam is expanded to a target diameter by a beam expander system to obtain a target expanded beam. The target expanded beam is adjusted by an optical path adjustment system to enter a diffractive optical element (DOE) shaping module for beam shaping to obtain a shaped beam. The shaped beam is focused by an optical focusing module to obtain a focused beam with the focus on a surface film of a to-be-processed product, and the to-be-processed product is moved such that a groove is scribed thereon. A laser scribing device is also provided.

The invention relates to a preparation method of an entangled light source based on a grating and a perfect vortex metasurface, and the method comprises the steps: providing a Gaussian beam, carrying out the linear polarization of the Gaussian beam in a specific polarization direction, and generating signal light and idle light through a periodically poled potassium titanate crystal; after the photons are collimated, the polarization states of the signal light and the idle light are changed through a 1 / 4 wave plate, and the signal light and the idle light are respectively converted into right-handed circular polarization and left-handed circular polarization; the Gaussian beam passes through the perfect vortex metasurface to obtain a geometric phase changing along with space; through the one-dimensional grating, the left-handed perfect vortex light and the right-handed perfect vortex light are separated to output an overlapped part entangled state; and respectively coupling the photons in the two paths into an optical fiber, and transmitting the photons to a single-photon detector to record a coincidence number.

The invention provides a nonlinear refractive index measurement system and method based on dual-optical-path interference, and relates to the technical field of nonlinear optical measurement, the system comprises a first laser emission unit, a first light splitting device, a second light splitting device, an interference device, a to-be-measured sample, a second laser emission unit and a measurement unit; the first laser emission unit generates a Gaussian beam; the first light splitting device splits the Gaussian beam into a sample beam and a reference beam which are parallel to each other; the second light splitting device splits the sample light beam and the reference light beam which are parallel to each other into two paths; the first sample light beam and the reference light beam enter a to-be-tested sample; the second laser emission unit generates a pumping light beam, and the pumping light beam is emitted to the sample to be measured along the light path of the first sample light beam; the interference device generates interference between the two sample light beams and interference between the two reference light beams; the measuring unit is used for collecting interference images, analyzing the interference images and calculating the nonlinear refractive index of the to-be-measured sample. The system is not easily influenced by the environment.