15 results about "Fresnel diffraction" patented technology

The invention discloses a high-angular-resolution wavefront measurement method and system based on random structure diffraction, and relates to the technical field of optical information measurement. According to the wavefront measurement method, phase modulation of incident light is realized by using a disordered diffractive optical element (DOE) in random binary phase distribution, and complex incident wavefront coding is realized through a Fresnel diffraction effect. The mapping relation between the diffraction pattern and the incident angle is further pre-calibrated through an experiment, and the wavefront to be measured is reconstructed in combination with a wavefront reconstruction algorithm. According to the scheme provided by the invention, the mapping relation between the DOE diffraction pattern and the incident angle is pre-calibrated through an experiment, accurate decoding of a local incident angle can be realized, a regional wavefront reconstruction algorithm is further combined, wavefront measurement with a large dynamic range, high spatial resolution and high angular resolution is satisfied, and the measurement precision is improved. And the method has higher reconstruction precision and real-time performance and better anti-noise capability.

The invention relates to the technical field of optical system design and optimization, and discloses a bifocal optical system optimization method based on a fundamental mode Gaussian beam. The method comprises the following steps: constructing a light field transmission model based on a generalized Huygens-Fresnel diffraction principle, and calculating to obtain an emergent field and on-axis light intensity distribution after passing through a bifocal system. A light intensity main maximum value point is identified, and the offset between the light intensity main maximum value point and a geometric focus is calculated, so that the occurrence criterion of a quantitative focus switching phenomenon is formed, and the stability of the focus is analyzed. And on this basis, joint iterative optimization is carried out on the beam truncation parameters and the Fresnel number, system parameters are adjusted until the stability meets a preset threshold, and finally an optimized system configuration scheme is output. According to the method, focus position jump caused by the physical optical effect can be effectively pre-judged and inhibited in the design stage, and the reliability and stability of the bifocal system in actual work are improved.

The invention relates to the technical field of pulse light sources, in particular to a space-time self-focusing generation method of a special space and time correlation partial coherence pulse light source, which comprises the following steps of: constructing a mutual coherence function of the special space and time correlation partial coherence pulse light source in a space domain and a time domain; the function is substituted into a generalized Huygens-Fresnel diffraction integral formula; obtaining an expression of a mutual coherence function of the special space and time correlation partially coherent pulse light source at any spatial position z by using the formula; overlapping the two space points and the two time points to obtain a space-time intensity expression of the special space and time correlation coherent pulse light source; the space-time intensity of the special space and time correlation partially coherent pulse light source has a space-time self-focusing phenomenon when being transmitted in a dispersive medium. According to the method, Lorentz function regulation and control are respectively carried out on a space coherence structure and a time coherence structure of a special space and time correlation partial coherence pulse light source, and the self-focusing phenomenon of the pulse light source in transmission can be obtained.

The invention provides an integrated super-resolution read-write objective lens and a preparation method thereof, the integrated super-resolution read-write objective lens is a single diffractive optical element, the surface of the element is provided with a preset microstructure, the microstructure is a binary or multi-step stepped embossment structure, and the surface of the element is provided with a plurality of microstructures. The microstructure is designed to simultaneously implement at least two optical transformations on an incident beam. According to the invention, functions of focusing, spiral phase modulation and the like simultaneously occur on the surface of the same element, light beams do not need to be transmitted among different elements, and phase distortion caused by effects of Fresnel diffraction and the like is eliminated; secondly, the excitation light and the suppression light pass through the same integrated element, and the relative position relation of the excitation light and the suppression light is accurately fixed by a microstructure on the surface of the element, so that the auto-collimation of a light path is realized, and the stability and robustness of the system are improved; besides, the negative dispersion characteristic of the diffractive optical element is utilized, inherent dispersion of the material is efficiently compensated or eliminated on a single element, a complex lens group is not needed, and an efficient and simple achromatic scheme is provided.

The invention relates to the technical field of pulse light sources, in particular to a method for simultaneously generating space-time self-splitting and self-focusing of a pulse light beam. The method specifically comprises the following steps: constructing a mutual dry function of a pulse light source in a space domain and a time domain; the mutual coherence function has a cosine-multi-Gaussian correlation form in a space domain and a time domain; the mutual dry function is substituted into a generalized Huygens-Fresnel diffraction integral formula; obtaining an expression of a mutual coherence function of the pulse light source at any position z in the space by utilizing the formula; overlapping the two space points and the two time points to obtain a space-time intensity expression of the pulse light source; when the time-space intensity of the pulse light source is transmitted in the dispersive medium, time-space self-splitting and self-focusing phenomena occur; according to the method, the phenomena of self-splitting and self-focusing of the pulse light source in transmission can be obtained; meanwhile, the self-splitting waveform and the self-focusing degree of the pulsed light in the transmission process can be flexibly controlled. The method can be applied to a laser underwater communication system and can be used for underwater laser processing.

The invention provides a single-frame non-time-sequence color holographic display system and method. The system comprises a red, green and blue three-color laser, a beam expanding and collimating system, a first polarizer, a spatial light modulator, a beam splitter and a band-limited filtering plane which are sequentially arranged along a light path, the spatial light modulator is connected with a computer and is used for loading a single phase type hologram generated through an iterative optimization algorithm; according to the iterative optimization algorithm, a phase hologram is generated based on a Fresnel diffraction model and a stochastic gradient descent method, laser emitted by a red-green-blue three-color laser is irradiated to a spatial light modulator through a beam splitter, modulated by the hologram in the spatial light modulator and then transmitted to a band-limited filtering plane, and a single-frame non-time-sequence color holographic image is reproduced. According to the invention, the wavefront information of the color object can be completely recorded and reproduced only by using one hologram without depending on high-refresh-rate equipment or complex synchronous control, so that the light path structure is effectively simplified, the cost is reduced, and the reproduction quality and stability of the image are improved at the same time.

The application relates to the technical field of optical system design and optimization, and discloses a double-focus optical system optimization method based on a fundamental mode Gaussian light beam. The method comprises the following steps: constructing an optical field transmission model based on a generalized Huygens-Fresnel diffraction principle, and calculating an exit field and an on-axis light intensity distribution after passing through a double-focus system. The occurrence criterion of a quantitative focal switch phenomenon is formed by identifying a light intensity main maximum point and calculating the offset amount of the main maximum point and a geometric focal point, and then the focal point stability is analyzed. On this basis, the light beam truncation parameter and the Fresnel number are jointly iteratively optimized, the system parameters are adjusted, until the stability meets a preset threshold, and finally an optimized system configuration scheme is output. The method can effectively predict and inhibit the focal point position jump caused by physical optical effects in the design stage, and improves the reliability and stability of the double-focus system in actual work.

The invention relates to the technical field of photoetching, in particular to an optical waveguide master mask defect self-adaptive photoetching method based on Talbot self-imaging, which comprises the following steps of: calculating a Talbot self-imaging distance by collecting a design period and an exposure wavelength parameter of an optical waveguide master mask, and driving a substrate coated with photoresist to be accurately positioned to the distance; after positioning is completed, coherent light output is started, meanwhile, the substrate is controlled to perform in-plane periodic motion, distortion components caused by defects are optically counteracted by a diffraction light field in the propagation process through the Fresnel diffraction effect, and homogenized light intensity distribution is generated; and after the distribution is recorded by the photoresist, a grating structure is formed through development, and the optical waveguide template is prepared through etching and deposition processes. Defect suppression can be realized on the optical level, the structural integrity and preparation consistency of the template are improved, the scrap demand of the mother set is reduced, and the production cost is reduced.

The application provides a modeling method for three-dimensional blur characteristics of a traditional optical microscope, and belongs to the technical field of optical microscopic observation. The method comprises the following steps: establishing an optical amplitude expression of an arbitrary point on an imaging plane in an optical system based on Fresnel diffraction theory; constructing a relationship between object distance variation and image distance variation without ideal object distance by using a geometric relationship between a diffraction spot diameter and an observed object; deducing an optical amplitude expression of the arbitrary point on the imaging plane containing object distance variation from the optical amplitude expression of the arbitrary point on the imaging plane in the optical system and the relationship between the object distance variation and the image distance variation without the ideal object distance; deducing an optical intensity distribution expression of the arbitrary point on the imaging plane from the optical amplitude expression of the arbitrary point on the imaging plane containing the object distance variation; and establishing a relationship between blur degree and defocus depth variation according to the optical intensity distribution expression of the arbitrary point on the imaging plane, so as to obtain a variation law of the blur degree of the traditional optical microscope system.

The invention provides a hologram rapid generation method based on multi-layer wavefront recording plane accurate diffraction. The method comprises the following four steps of: 1, dispersing a 3D object into independent object points, and dividing the object points into n object point groups with different depths according to depth information; and 2, for any object point group, introducing a corresponding wavefront recording plane between the 3D object and the holographic surface, and according to the Fresnel diffraction theory, respectively calculating a sub-hologram of the independent point source of each object point group on the corresponding wavefront recording plane. And a third step of performing optimization segmentation on each sub-hologram based on visual area characteristics to obtain corresponding effective diffraction regions, and performing coherent superposition on the effective diffraction regions to obtain complex amplitude distribution on the wavefront recording plane. And 4, calculating diffraction from each wavefront recording plane to the holographic surface based on an angular spectrum diffraction theory to obtain a corresponding hologram of each object point group on the holographic surface. And finally, coherently superposing the holograms to obtain a final hologram. Due to the fact that redundant information is eliminated, the calculation complexity is reduced, and the method greatly improves the calculation speed of the hologram while maintaining the reconstruction quality.

The application belongs to the technical field of neutron scattering, and particularly relates to a dynamic range improvement and background suppression integrated collimation / beam blocking device and method. Through integrated collimation and multi-stage beam blocking collaborative design, the parasitic background caused by Fresnel diffraction and edge scattering is reduced. Through a closed-loop tracking compensation mechanism, the beam center deviation caused by thermal drift and mechanical drift is reduced, the low-q region artifact risk is reduced. Through the replaceable absorber cassette, multi-working-condition quick switching is realized, the high-throughput and high-dynamic-range measurement requirements are considered, through the sample environment module local shielding and opening angle collaborative optimization, the additional scattering introduced by extreme environments such as high temperature and high pressure is reduced, through the dynamic mask reconstruction process, the effective data retention rate in the low-q region is improved and the measurement repeatability is improved. It simultaneously realizes that the background in the low-q region is significantly reduced, the baseline stability is improved, the beam blocking coaxial relationship can still be maintained under the condition of slow beam drift, and the error of the reconstruction system is reduced.

The invention discloses a real-time parallax optimization method for adaptive light field rendering, a medium and equipment. The method comprises the following steps: acquiring a dynamic microscopic image sequence and an auxiliary depth map; inputting the data into a double-flow architecture of a spatial-temporal feature extraction network for preprocessing, and outputting a standardized spatial-temporal feature tensor; inputting the standardized spatio-temporal feature tensor into a pre-trained spatio-temporal double-flow cascade network model for processing, and outputting an initial disparity map; a microscope optical parameter and an initial disparity map are input, AO-Net processing is utilized, a polynomial coefficient is generated, a light field propagation model is utilized, the polynomial coefficient is optimized based on the Fresnel diffraction principle, and corrected light field data are output; inputting an initial disparity map, processing the initial disparity map by adopting a grading strategy, and outputting an optimized disparity map; corrected light field data and an optimized disparity map are input, and a physically optimized 3D structure is output through 3D reconstruction and physical constraint; and inputting the physically optimized 3D structure and the optimized disparity map, and executing real-time rendering. According to the invention, the problem of poor 3D imaging effect is solved.

This invention discloses a numerical simulation method for optical field transmission based on matrix operations, belonging to the field of optical field transmission research. First, the matrix of the optical transmission system is determined according to the task requirements. Then, the generalized Huygens-Fresnel diffraction integral is transformed into a summation form in discrete rectangular coordinates, and further transformed into a matrix product form. Using the determined optical transmission system matrix parameters and the determined numerical integration algorithm matrix, the target optical field is finally calculated using the input optical field and the algorithm matrix. This invention avoids the Gibbs phenomenon, confusion, and tailing effects caused by Fourier transform. This invention allows for arbitrary selection of the number of grid points in the target optical field, offering flexibility and economy.

The invention relates to the technical field of optical waveguide master mask defect compensation photoetching, in particular to a composite optical waveguide master mask defect compensation photoetching system and method, a nonlinear decoupling model of grating period-wavelength-Talbot distance is constructed by adopting a Newton-Rafson iteration method, and a multi-physical field compensation matrix is generated by combining an FDTD simulation correction dispersion effect. The positioning unit realizes sub-nano-scale substrate positioning through homogeneous coordinate transformation and thermal drift PID control, and the motion control module utilizes Fourier series filtering to optimize trajectory planning and cooperates with liquid crystal phase modulation and polarization state real-time calibration to maintain light field uniformity. The defect suppression unit fuses Fresnel diffraction integral and deep learning feature matching, and realizes time-space domain cooperative suppression of high-frequency defects through a double average algorithm. And the quality verification module establishes a closed-loop feedback network, and a parameter acquisition model is dynamically optimized by utilizing machine learning, so that the technical contradiction that a defect suppression blind area and the system complexity are difficult to consider in the prior art is effectively solved.

The invention relates to a hologram intelligent compression and reconstruction system and method, and belongs to the field of hologram processing. Comprising the step of realizing high-efficiency compression and high-quality reconstruction of holographic data through three core technologies of dynamic range segmentation, perception weight optimization and adaptive quantization when a CCD records a hologram. The method comprises the following steps: firstly, segmenting a hologram into a high dynamic range (HDR) region and a low dynamic range (LDR) region by adopting a local feature analysis technology and combining a dynamic threshold value; secondly, enhancing high-frequency information retention by using a frequency sensitive weight; and iteratively optimizing parameters through a code rate control module, implementing nonlinear quantization on an HDR region, and implementing linear quantization on an LDR region. In the reconstruction stage, a Fresnel diffraction model is adopted for physical reduction, and a holographic reproductive image is obtained. According to the method, a high compression ratio is achieved in airspace compression, and meanwhile high quality of a reconstructed image of the compressed hologram is guaranteed.