8 results about "Fresnel diffraction" patented technology

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 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 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 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 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.