181 results about "Self-focusing" patented technology

The invention discloses a light path system based on a gas-filled hollow-core optical fiber, and the system comprises a spectrum broadening device which comprises a first gas extraction chamber, a gas inlet chamber and a second gas extraction chamber, the first gas extraction chamber and the second gas extraction chamber are located at the two ends of the gas inlet chamber respectively, and the first gas extraction chamber and the gas inlet chamber are separated through a first sealing part; the second air exhaust chamber and the air inlet chamber are separated through a second sealing piece; the spectrum broadening device is internally provided with a hollow-core optical fiber and is provided with at least one through hole penetrating through the pipe wall of the hollow-core optical fiber, the two ends of the hollow-core optical fiber penetrate through the first sealing piece and the second sealing piece respectively so that the two ends of the hollow-core optical fiber can be communicated with the first air suction chamber and the second air suction chamber respectively, and the through hole is located in the air inlet chamber. The two ends of the hollow-core optical fiber are subjected to air exhaust, so that the ionization rate and the self-focusing effect generated when the laser is output after the spectrum of the inflated hollow-core optical fiber is broadened can be remarkably reduced, the requirement for improving the power input of the laser is met, and a light path system can bear higher laser monopulse energy compression.

The invention discloses an atmospheric transmission vortex light topological charge detection method based on light intensity distribution. The method comprises the following steps: firstly, generating a vortex light beam with a self-focusing characteristic, simulating an atmospheric turbulence environment by adopting a multi-phase screen method, calculating a transmission process of the light beam under an atmospheric turbulence condition by adopting a step-by-step Fourier method, and obtaining a light intensity distribution image at a focusing point; self-adaptive cutting and normalization preprocessing based on the mass center are carried out on the light intensity distribution image; and constructing a ResNet18 deep learning model containing eight residual blocks, and training by using the constructed data set to realize automatic identification of the topological charge number.

The invention belongs to the technical field of laser vibration measurement, and provides a self-focusing laser Doppler vibration measurement method and system capable of resisting self-vibration of an optical fiber, and the method comprises the steps: adding a compensation light path which is used for sensing and generating reference light which is equal to an interference signal in amplitude and is opposite to the interference signal in real time in a Doppler vibration measurement light path, and taking the minimum mean square error as a self-adaptive matching criterion; interference phases obtained by synchronous demodulation of the compensation light path and the main light path are subjected to adaptive matching and cancellation in amplitude and phase dimensions, residual errors of vibration of the vibration measurement system and other environmental interferences are suppressed below noise of the vibration measurement system, and the purpose of balancing and weakening optical fiber vibration interferences in an instrument is achieved. The influence of the vibration factor of the instrument is reduced, and the interference influence is accurately eliminated through amplitude and phase matching by a demodulation algorithm corresponding to a compensation light path; meanwhile, by dynamically observing and updating the return light intensity threshold, low-frequency disturbance is resisted, and accurate automatic focusing is achieved.

The invention discloses a method for generating a multi-focus circular beam based on an all-dielectric metasurface, and the method specifically comprises the following steps: 1, constructing the all-dielectric metasurface which is composed of a plurality of arranged super atoms; the super atom comprises a square SiO2 substrate, and a rectangular Si nanorod is arranged on the SiO2 substrate; and 2, irradiating the all-dielectric metasurface by using left-hand circularly polarized light as incident light, and modulating the incident light by using a geometric phase and a propagation phase, so that emergent light of the all-dielectric metasurface forms a right-hand circularly polarized multi-focus circular light beam. According to the invention, the circularly symmetrical light beams with a plurality of self-focusing focuses can be efficiently and flexibly generated, and the number and the focal depth of the focuses can be adjusted as required.

The invention belongs to the technical field of radar signal processing, discloses a plasma sheath multi-order dispersion effect error compensation method, system, equipment, medium and program product based on two-step self-focusing processing, and aims to solve the problem of plasma sheath multi-order dispersion effect error influence of radar in the hypersonic flight vehicle imaging detection process. Obtaining a strong scattering point target in the image through strong point target search, and constructing a dispersion effect error compensation image matrix; based on a maximum contrast self-focusing processing principle and an image focusing theory, iteratively processing and compensating second-order and third-order phase errors of a dispersion effect; outputting an image after the multi-order dispersion effect error compensation, and realizing the accurate compensation of the multi-order dispersion effect error of the target wrapped by the plasma sheath; systems, devices, media for implementing the method, program products including computer programs implementing the method; the method has the characteristics of high dispersion effect error compensation precision, high compensation efficiency, strong adaptability and simple compensation processing steps.

The invention belongs to the technical field of optical measurement, and discloses an implementation device and method of a single-photon spectrograph, and the device comprises a spectral wavelength scanning module which is used for collecting a wide-spectrum optical signal, carrying out the wave division processing, and calculating the photon counting change rate between adjacent wavelengths; wavelength stepping is dynamically adjusted according to the photon counting change rate, self-adaptive scanning of spectrum change is achieved, and a single-spectrum optical signal is output; the self-focusing detection module is used for converting the single-spectrum optical signal into a photon event through a preset array channel; in a preset time window, calculating the variance and the Shannon entropy of each photon event, and constructing a local uncertainty index; performing spectral domain self-focusing and resampling according to the local uncertainty index to obtain photon counting data; high-precision, high-stability and high-efficiency spectrum light signal detection and visual analysis are realized.

The invention discloses an SAR image self-focusing distortion correction method and device, and belongs to the technical field of synthetic aperture radars. The method comprises the following steps: carrying out distance blocking and orientation sub-aperture division on a defocused SAR image, selecting a sample, and carrying out orientation decompression to a phase historical domain; performing azimuth dechirp processing on the sub-aperture data in each distance sub-block, and estimating a phase error through a standard PGA algorithm; after splicing sub-aperture phase errors and removing an overall linear phase, performing phase compensation and azimuth compression to obtain a focused image; and for azimuth distortion caused by residual linear phase of the compensated image, extracting a phase error linear term coefficient through a sliding window, deducing an azimuth shift distance in combination with Fourier transform time shift characteristics, and finally performing shift correction by adopting sinc interpolation. According to the method, the image focusing quality is improved, and meanwhile, the ground feature continuity and the image resolution are kept.

This invention discloses a phase compensation method for ship targets using ISAR based on block phase gradient autofocus. The steps include: pulse compression; range cell migration correction; range-oriented block segmentation; block phase compensation; calculation of the offset between adjacent image blocks; and image block alignment and stitching. This invention performs range-oriented block segmentation of the target echo, overcoming the shortcomings of existing technologies that ignore the spatial variation of rotational phase error, leading to defocusing in ship imaging, thus improving the accuracy of phase compensation and achieving good image focusing effect. Because this invention uses a phase gradient autofocus algorithm to compensate for the phase error within each block, and then uses a cross-correlation method to align and stitch the images of each block region, it overcomes the shortcomings of parameter estimation methods, such as complexity, time consumption, and poor real-time performance, and has the advantages of simple implementation, high efficiency, and strong real-time performance.

The invention discloses a block self-focusing ISAR (inverse synthetic aperture radar) imaging method and system based on an FPGA (field programmable gate array), and the method comprises the steps: obtaining ISAR echo data, and sequentially carrying out the preprocessing and global self-focusing processing, thereby obtaining a global self-focusing correction matrix; dividing the global self-focusing correction matrix into a plurality of sub-matrix blocks in a sliding window partitioning manner; performing minimum entropy self-focusing processing on each sub-matrix block to generate an optimized sub-matrix block; performing fast Fourier transform on the optimized sub-matrix blocks in the azimuth direction to generate two-dimensional image data; determining an offset according to an overlapping region of the adjacent sub-matrix blocks, performing cyclic shift processing on the two-dimensional image data corresponding to the current optimized sub-matrix block in the azimuth direction based on the offset, and aligning the two-dimensional image data corresponding to the previous adjacent optimized sub-matrix block; and outputting the aligned corrected two-dimensional image data as an ISAR imaging result. According to the invention, the azimuth focusing performance is improved, and the overall imaging quality is obviously improved.

The invention relates to the technical field of ultrafast laser, in particular to an ultraviolet laser damage inhibition method and device for a fused quartz optical element, and the method comprises the steps: obtaining oxy-18 modified DKDP crystals with oxy-18 isotope abundance higher than natural abundance; preparing the oxy-18 modified DKDP crystal into a wave plate matched with a preset ultraviolet laser wavelength; in an ultraviolet laser light path of a laser inertial confinement fusion device, a wave plate is arranged between a linear polarization state output end of ultraviolet laser and a fused quartz optical element; and enabling ultraviolet laser to sequentially pass through the linear polarization state output end and the wave plate to form circularly polarized light, and irradiating the circularly polarized light to the fused quartz optical element. The invention aims to realize the small-scale self-focusing effect of actively inhibiting fused quartz and solve the technical problem that a traditional material cannot be used as a large-aperture wave plate due to over-high transverse stimulated Raman scattering.

The present invention relates to the technical field of three-phase flow detection, and provides a fluorescent fiber optic probe device for three-phase flow detection, comprising: a packaging shell; a sapphire probe disposed within the packaging shell; a connected small-diameter self-focusing lens and a large-diameter self-focusing lens located above the sapphire probe; an integrated fiber bundle structure divided into a transmitting fiber and a receiving fiber within a main cavity; a laser transmitting module connected to the transmitting fiber; a collimating lens located above the receiving fiber; a trapezoidal waveguide structure located above the collimating lens; a first optical focusing assembly and a second optical focusing assembly disposed side by side above the trapezoidal waveguide structure, with a reflective volume holographic grating disposed below the first optical focusing assembly; a first photoelectric conversion module and a second photoelectric conversion module; and a main control module. The device of the present invention can effectively avoid optical power attenuation caused by optical fiber splitting and filters, thereby ensuring optical signal transmission efficiency and detection accuracy.

The invention discloses a handheld high-resolution millimeter-wave synthetic aperture radar imaging method. The method comprises the following steps: mixing signals acquired by a handheld high-resolution millimeter-wave radar to obtain intermediate-frequency signals; performing fast Fourier transform processing and residual video phase removal on the intermediate frequency signal; calculating the frequency response corresponding to the distance between the phase center of the radar antenna and the pixel point through linear interpolation; obtaining a preliminary result according to backward projection imaging; calculating position error estimation according to a minimum entropy self-focusing algorithm; and track correction is carried out according to the position error estimation, and then backward projection imaging is carried out again. The minimum entropy self-focusing backward projection algorithm provided by the invention takes image entropy minimization as an optimization target, compensates the position error of the phase center of the radar antenna through a coordinate descent method, does not need to depend on an external sensor, and effectively improves the imaging definition, thereby achieving compact and efficient imaging. The invention discloses a light and independent handheld high-resolution millimeter wave synthetic aperture radar system.

The invention provides a circumferential synthetic aperture sonar imaging motion compensation method based on a corner reflector, and the method comprises the steps: S1, carrying out the projection imaging of echo data after matched filtering, and determining the height of the corner reflector through an image variance; s2, according to the height of the corner reflector, the focusing position of the corner reflector is determined through the preliminary imaging result; s3, the distance between the corner reflector and the sonar is calculated according to the echo data when echoes are received each time; and S4, correcting the position of the sonar according to the focusing position of the corner reflector determined in the step S2 and the distance determined in the step S3, and performing projection imaging according to a new sonar position and echo data. According to the method, the corner reflector is used as an imaging reference target, the image quality of circumferential synthetic aperture imaging is improved, and the method is of great significance in reducing the calculation time of a self-focusing algorithm, improving the target imaging quality and the like.

The application discloses a method for generating an ultralong focal depth array beam, and belongs to the technical field of grating manufacturing. The method comprises the following steps: constructing a Bessel beam excitation phase and a circular Airy beam excitation phase, constructing a composite phase distribution according to the array Bessel beam excitation phase and the array circular Airy beam excitation phase, and encoding the composite phase distribution to a metasurface; irradiating the metasurface with a linear polarization state plane wave, so that a left-handed circular polarization component excites an array Bessel beam, and a right-handed circular polarization component excites an array circular Airy beam; the array circular Airy beam is converted into a Bessel propagation mode after self-focusing, is spliced with the array Bessel beam in an axial direction to form a continuous light field distribution, and an ultralong focal depth array beam is obtained. The method can be applied to the fields of parallel laser processing, three-dimensional microscopic imaging and microparticle manipulation, and can extend the focal depth of the array Bessel beam while keeping the transverse resolution close to the diffraction limit.

The present invention discloses a self-focusing method and device based on an affine coordinate system BP for a high squint SAR, the method comprising: performing range pulse pressure and coarse compensation on the received original echo signal to obtain a coarse compensation signal; establishing an affine coordinate system PX with the beam center P as the origin in the imaging scene based on the coarse compensation signal; ac Y ac Z ac , and in this coordinate system X ac Y ac The imaging scene grid is established within a plane; the imaging scene grid is divided into multiple subgrids, and rapid BP imaging and spectrum tilt correction processing are performed on the coarse compensation signal on a subgrid-by-subgrid basis to obtain multiple coarsely focused subimages; a phase error structure of different coarsely focused subimages is constructed to achieve estimation and inversion of the two-dimensional phase error; the two-dimensional phase errors corresponding to the different coarsely focused subimages are compensated into their respective coarsely focused subimages to obtain multiple finely focused subimages; and the multiple finely focused subimages are spliced ​​to obtain a final finely focused image. This invention can improve SAR imaging quality in high squint modes.

The invention discloses a remote high-depth-of-field LIBS self-focusing detection device for a lunar soil environment, and the device comprises a variable-curvature primary mirror which is provided with a central light through hole, and one side of the variable-curvature primary mirror is sequentially provided with a beam expanding assembly, a low-pass dichroscope, a focusing system, and a spectrometer; the multi-secondary-mirror zooming structure is arranged on the other side of the curvature-variable primary mirror; wherein the low-pass dichroscope corresponds to the transmitting end of the pulse laser; the variable-curvature primary mirror comprises a plurality of reflectors which are sequentially stacked from left to right, wherein the curvatures of the reflectors are sequentially increased. The multi-mirror zoom structure comprises a guide rail capable of rotating and axially moving; and the plurality of secondary mirrors with different curvature radiuses are sequentially arranged on the guide rail through the electronic clutch, and the secondary mirrors can diverge and reflect the light beams. According to the invention, the super-large depth of field with the axial depth of 1.5 cm is constructed by using the variable-curvature primary mirror, and the large-range coverage of the full life cycle area of the expanded plasma is realized.

The invention relates to a method for generating self-focusing by a Lorentz non-uniform correlation partially coherent pulse light source, which comprises the following steps of: firstly, by constructing a pulse light source with a Lorentz non-uniform time correlation structure, defining a time domain mutual coherence function of the pulse light source so as to represent pulse coherence characteristics; the mutual coherence function is based on the generalized Huygens-Fresnel principle, a mutual coherence function expression of the LNUC partially coherent pulse light source at the transmission distance z is deduced, and the coherence degree is in Lorentz distribution and has the non-uniform correlation characteristic. An average intensity expression is further obtained according to a mutual dry function expression, intensity distribution has a self-focusing phenomenon in evolution, and the characteristic has potential application value in the fields of pulse beam shaping and micromachining.

The invention relates to a terahertz video SAR (Synthetic Aperture Radar) fine imaging method, device and equipment and a medium. The method comprises the following steps of: approximating a distance difference into a linear function related to the speed of a platform, correcting range walk through a keystone method, considering the influence of the vertical distance from scattering points of different distance units to an air route on imaging quality in secondary phase error compensation, constructing a corresponding secondary phase error function, and meanwhile, calculating the imaging quality under the minimum entropy criterion. According to the method, secondary phase errors in radar signals are accurately compensated, after phase gradient self-focusing, the image is still affected by speckles, at the moment, an anisotropic extended filtering method is adopted, the influence of the speckles is restrained, and a fine terahertz video SAR image can be obtained through the method.

A dynamic 3D light scattering particle size distribution measurement device includes a polarization splitter for generating an s laser beam with perpendicular polarization and a p laser beam with parallel polarization that travels parallel to and spaced apart from the s laser beam. A lens is used to focus the s laser beam and the p laser beam onto a common focus area inside a sample holder holding a sample whose particle size is to be measured. An s light intensity detector measures a time-resolved s light intensity from s backscattered light from the focus area. An s-polarisation filter allows perpendicularly polarized light to pass, resulting in s measuring light, and includes a light detector for time-resolved intensity measurements of the s measuring light. A p light intensity detector measures a time-resolved p light intensity detects p backscattered light from the focus area, and includes a p polarization filter that allows parallel polarized light to pass. A light detector provides for time-resolved intensity measurement of the p measuring light, and an evaluation unit automatically calculates the particle size distribution from the time-resolved p light intensity and the time-resolved s light intensity.

This application relates to the field of space imaging technology and provides a method for decoupling translational and rotational motion in space-based microwave imaging of space targets based on parameter estimation. The method first uses adjacent cross-correlation and self-focusing methods to perform preliminary compensation for the translational motion components of the microwave imaging echo data. Then, using the first-order translational motion parameters fitted by the former as initial values ​​and minimizing the image entropy of the echo data as the cost function, it combines Keystone transform to optimize and compensate for the translational linear phase components. Next, it uses Keystone transform to compensate for the spatially varied range cell migration caused by the rotational motion components. Finally, it performs a second compensation for the residual translational motion components, obtaining echo data after almost complete compensation of the translational and rotational MTRC. By performing spatially varied phase error compensation and azimuth compression on this data, the imaging result of the space target can be obtained. This method achieves a balance between the efficiency and accuracy of parameter estimation, effectively improving imaging quality.

This invention provides a SA-ISAR autofocusing and calibration method based on sparse LVD, comprising: constructing an echo model of a sparse aperture maneuvering target; obtaining a sparse signal recovery model of the linear frequency modulated signal in the CFCR domain during the energy accumulation process by performing energy accumulation based on the CFCR domain under the echo model; solving the sparse signal recovery model based on the FSBL-LVD-CTF method to obtain an ISAR image; and performing lateral calibration processing on the ISAR image using the FSBL-LVD-CTF method to obtain the ISAR image calibration result. In this invention, the FSBL-LVD-CTF method combines the strong robustness of sparse Bayesian learning and the efficient processing capability of Lf distribution transformation for linear frequency modulated signals, while also suppressing cross terms through cross-term filtering of CTF to ensure reliable sparse recovery results, thereby improving the accuracy and robustness of ISAR imaging.

The invention discloses a high-definition digestive tract endoscope based on convective heat exchange. The high-definition digestive tract endoscope comprises a high-definition equivalent prism module, a self-focusing lead-in part connector, a self-focusing illumination light transmission system and an air convective heat exchange system, the center line of the lens group in the 3D high-definition equivalent prism module is perpendicular to the right-angle input surface of the equivalent prism and does not pass through the center of the right-angle input surface of the equivalent prism, so that the problem of 3D image linearization between an object space and an image space is solved; the self-focusing illumination light transmission system improves the transmission efficiency of illumination light and the free space rate in the inner cavity channel of the insertion part; the air convection heat exchange system conveys air to the head end of the insertion part of the high-definition digestive tract endoscope and an operation handle, heat generated by the high-definition imaging chip, the signal processing circuit board and the illumination light in the dodging lens set is taken away in a convection mode, and the heat leaves the high-definition digestive tract endoscope through the primary and secondary control valves.

The invention provides an SAR moving target self-focusing imaging method based on multi-frame correlation learning, and relates to the technical field of synthetic aperture radar imaging, and the method comprises the steps: building an observation model of a moving target echo signal according to an SAR working process and moving target motion characteristics; establishing an SAR moving target sparse reconstruction and self-focusing imaging model; constructing an iterative solution process of the SAR moving target sparse reconstruction and self-focusing imaging model by using an alternating direction multiplier method; constructing an SAR moving target self-focusing imaging network by deeply expanding the iterative solution process and combining with a moving target motion compensation module based on multi-frame correlation learning; and training the SAR moving target self-focusing imaging network through back propagation, and optimizing parameters of the SAR moving target self-focusing imaging network to obtain a final SAR moving target self-focusing imaging network. According to the method, the focusing imaging performance of the moving target can be ensured under the condition of signal sparse sampling, and the method has applicability to a complex moving target motion scene.

A shock wave generator comprising a base, a plurality of transducers positioned on the base, a control assembly electrically coupled to the plurality of transducers, and a first chamber with a first fluid. The first chamber is at least partially defined by the base. The shock wave generator further comprises a second chamber with a second fluid, a membrane positioned between the first chamber and the second chamber, and a circulation assembly fluidly coupled to the first chamber. The circulation assembly includes a pump that circulates the first fluid, a chiller that controls the temperature of the first fluid, and a degasser that removes bubbles from the first fluid.

The invention relates to a beach vortex light beam pattern recognition method based on cross phases. On the basis of a beach vortex light beam with a self-focusing characteristic, the beach vortex light beam mode identification method based on the cross phase is provided by combining the mode evolution influence of the cross phase on a light field in the transmission process. Conventional single-mode vortex light is in a circular ring shape, the accurate value of the topological charge cannot be accurately distinguished, and the method achieves accurate recognition of the topological charge value of the frontal vortex light beam with the self-focusing characteristic for the first time on the basis of a phase type spatial light modulator and a cross phase. And positive and negative topological charges can be accurately distinguished according to a mode evolution result. Compared with a traditional vortex light field capable of being stably transmitted, the method achieves a good effect in the aspect of detection of the vortex light field with the self-focusing characteristic, belongs to the field of light field regulation and control, and can be applied to design of optical elements.

The invention discloses a satellite-borne SAR (Synthetic Aperture Radar) self-focusing method and system for a long-time integral bunching mode, a computer and a storage medium, and the method comprises the steps: screening a strong scattering target region in a manner of taking the maximum contrast or maximum power as a target according to the size of a divided grid; a minimum entropy distance alignment algorithm based on a partial frequency spectrum is used to realize distance migration error estimation of a partial region, a mode of combining hamp filtering and polynomial fitting is used to realize full-scene distance migration error estimation, and a minimum entropy phase correction algorithm is used to realize phase error estimation of a partial region. All-scene phase error estimation is realized by combining a Savitzky-Golay filter and a polynomial fitting mode, and unified compensation processing is performed on an original all-scene image by applying all-scene range migration errors and a phase error estimation result, so that all-scene fine focusing is realized. According to the invention, large-scene full-image fine focusing under the condition of over 15 seconds of ultra-long synthetic aperture time can be realized.

The invention discloses a contact image sensor based on adaptive multispectrum, which relates to the technical field of image sensing and comprises a self-focusing lens array, a liquid lens array, an optical filter array, a driving circuit, an image sensing element and a control unit, according to the invention, by integrating the multi-band liquid lens array and the one-to-one corresponding optical filter arrays and combining an independent driving circuit and an adaptive control algorithm, mechanical-free automatic focusing in a wide spectral range is realized, a mechanical moving part in a traditional scheme is not needed, the problem of a complex structure caused by mechanical switching in multi-spectral imaging is solved, and the imaging efficiency is improved. By configuring an independent voltage regulation and control mechanism for each liquid lens, focal length requirements of different spectral bands can be accurately matched, the problem that part of band images are blurred due to a fixed focal length is avoided, delay generated by mechanical switching is eliminated by means of the quick response characteristic of the liquid lenses, and the multi-spectral scanning efficiency is improved.

The application provides a terahertz SAR high-efficiency self-focusing imaging method and system based on RB-PCA, comprising: obtaining original echo signal data and performing pretreatment; performing distance block in the distance direction on the pretreated echo signal data to obtain a plurality of distance blocks, performing sub-aperture segmentation in the distance block for each distance block to obtain a plurality of sub-aperture signal data; performing desquamation processing on each sub-aperture signal data to obtain desquamation signal data; performing PCA processing on the desquamation signal data and selecting a characteristic vector with the largest characteristic value as a target characteristic vector; obtaining each sub-aperture phase error gradient estimation value through adaptive PGA estimation on the target characteristic vector; obtaining two-dimensional space-varying phase errors of each distance block through global splicing and fusion on each sub-aperture phase error gradient estimation value; and performing phase compensation and azimuth compression on the pretreated echo signal data based on the two-dimensional space-varying phase errors to obtain focused imaging results.

The application provides a background ionosphere correction method suitable for high-orbit SAR ground surface coordinate system imaging, which comprises the following steps: receiving a high-orbit SAR echo signal, obtaining corresponding background ionosphere TEC data of the high-orbit SAR echo signal, and performing coarse compensation on the background ionosphere phase error of the echo signal according to the ionosphere TEC data; performing high-orbit SAR ground surface coordinate system imaging on the data after coarse compensation to obtain a large scene image; estimating the phase error of the phase of the echo signal without coarse compensation by using a self-focusing algorithm and the large scene image to obtain an estimation result; fitting the estimation result by using a least square method, determining a coefficient matrix of an ionosphere space-time coupling model corresponding to the large scene image according to the fitting result; dividing the large scene image into a plurality of sub-scene images, performing fine compensation on the background ionosphere phase error of each sub-scene image according to the determined coefficient matrix and each sub-scene image, and completing the correction, so that the correction of the high-orbit SAR ground surface coordinate system imaging is realized.

This invention discloses a self-focusing vortex spin terahertz transmitter and its application, comprising a glass substrate, a spin terahertz thin film, and a magnet pair. The spin terahertz thin film is composed of a ferromagnetic material layer, a heavy metal non-magnetic material layer A, and a heavy metal non-magnetic material layer B. The ferromagnetic material layer is disposed on the upper surface of the glass substrate, and the heavy metal non-magnetic material layers A and B are arranged in a spiral alternating pattern on the outer surface of the ferromagnetic material layer. This invention has a simple structure. By fabricating two specially arranged heavy metal non-magnetic material layers with equal and opposite spin Hall angles on the ferromagnetic material, a spiral spin terahertz Fresnel zone plate is constructed, enabling the generated vortex spin terahertz waves to have a focusing function, thereby improving the integration of the vortex spin terahertz transmitter.