39 results about "Periodic grating" patented technology

This invention belongs to the field of wavelength division multiplexing optical communication technology, specifically relating to a reverse coupler based on a thin-film lithium niobate platform. The reverse coupler includes: a lithium niobate-on-insulator substrate, a first waveguide, a second waveguide, and a coupling region. The first and second waveguides are disposed in the device layer of the lithium niobate-on-insulator substrate. The first and second waveguides are arranged in parallel along the light propagation direction within the coupling region. A periodic grating perturbation structure is disposed on the first and / or second waveguides. This reverse coupler utilizes the grating perturbation structure to ensure that the modes of the two waveguides satisfy the phase matching condition. The optical signal input to one waveguide is reverse-coupled to the falling port of the other waveguide. Utilizing the large photoelectric coefficient of lithium niobate material, this reverse coupler can tune its spectrum under specific conditions by applying a voltage.

A sub-wavelength grating optical film comprises a plurality of one-dimensional periodic grating units repeatedly arranged side by side. Each grating unit with a period of p comprises a first medium, a second medium, a third material, a fourth material, a fifth material, a sixth medium and a seventh medium, wherein the sixth medium serving as a substrate and the seventh medium serving as a covering layer are respectively arranged on bottom and top of each grating unit periodically arranged side by side. By controlling grating period and refractive index, incident blue-violet light meets condition that a diffraction angle in a layer with highest refractive index is smaller than 90 degrees; and by adjusting duty ratio of the grating and the thickness of each layer of material, transmitted light energy of the blue-violet light wave band is the lowest so that harmful blue-violet light is isolated.

This invention relates to the field of mechanical seals, specifically a dynamic measurement method for the end face clearance of a mechanical seal, comprising the following steps: S1: setting a periodic grating structure on the non-sealing surfaces of the rotating and stationary rings of the mechanical seal; S2: acquiring a dynamic image sequence of the periodic grating structure during the operation of the mechanical seal; S3: processing the acquired dynamic image sequence to extract the phase information of the periodic grating structure and obtain phase change data; S4: calculating the relative displacement and relative rotation angle between the sealing end faces of the rotating and stationary rings based on the phase change data; S5: monitoring, providing early warning, and evaluating the state of the mechanical seal. This invention provides a dynamic measurement method for the end face clearance of a mechanical seal. This invention enables non-stop, non-contact online detection of the end face clearance of a mechanical seal.

Disclosed is a surface etched grating semiconductor laser with periodic pumping structure. The structure includes a lower doped dielectric layer, a multiple quantum well active layer, a ridge-shaped doped dielectric layer, periodic grating grooves formed on the ridge-shaped doped dielectric layer and a top electrical contact layer forming ohmic electrical contact with electrical contact regions between the grating grooves. Carriers are injected through the periodic electrical contact layer, flow through the electrical contact regions, spread laterally when reaching the bottom of the grating grooves, and then continue to spread to the multiple quantum well active layer. In a case of uniform distribution, a laser based on refractive index modulation is realized. In a case of non-uniform distribution, a laser with mixed modulation is realized by introducing additional gain modulation.

Optically Scanned Antenna and System Comprising Such an Antenna The present invention relates to an optically scanned antenna (10) comprising: - a light source (12) generating a beam, - a beam splitter unit (14) dividing the generated beam into N sub-beams, - a control unit (16) for the relative phase of the N sub-beams, - an integrated photonic circuit (11) comprising an array of extractors (34), the extractors (34) being arranged in a first two-dimensional periodic grating, each extractor (34) being adapted to extract a respective sub-beam from a plane of the integrated photonic circuit (11), - a lens array (20) arranged in a second two-dimensional periodic grating, the first and second gratings having the same arrangement, and - a displacement unit (22) for displacing the first and second gratings relative to each other. Figure for the abstract: Figure 1

A security element is arranged to safeguard valuable articles, featuring a motif layer based on a liquid-crystal material that forms a latent motif. The security element includes a first embossing varnish layer on a carrier film, with a motif layer partly on this varnish, based on nematic liquid crystals. A second embossing varnish layer covers the surface. The facing surface of the first varnish has an embossing with at least two regions featuring different alignment structures, creating a second latent motif. These alignment structures include an aperiodic grating with varying grid spacing. The motif layer, forming a first latent motif, overlaps the second latent motif regions. The nematic liquid-crystal material is aligned by the motif-forming regions, producing a discernible motif when viewed through a polarizer. The second varnish layer also has an embossing for a micro-optical relief structure and reflection-enhancing coating.

The invention relates to a high-sensitivity streak camera ultrafast scanning image enhancement and noise reduction method, and belongs to the technical field of ultrafast imaging and signal processing. The method mainly comprises the following steps of: performing spatial modulation on three-dimensional image data coded by a spatial coding element through a periodic grating; carrying out compression imaging on the modulated three-dimensional image data by the streak camera to form a two-dimensional observation image; an ADMM-TV algorithm is adopted to carry out image decoding, and a three-dimensional image containing a periodic modulation structure is recovered; after the three-dimensional image is reconstructed, effective fringe information in the modulated image is further extracted, high-frequency modulation residues are removed, and denoising of the interference fringe image is achieved. Physical separation of signals and noise is achieved through periodic grating modulation, high-frequency interference such as space charge noise can be restrained, the signal-to-noise ratio and contrast ratio of images are improved, and accuracy and stability of diagnosis of an ultrafast imaging system of a VISAR speed interferometer are improved.

Disclosed is a hybrid integrated single-longitudinal-mode narrow-linewidth compound cavity laser, which comprises: a distributed feedback gain chip (1), a micro-ring resonant cavity; the two ends of the distributed feedback gain chip are respectively coated with a first anti-reflection film (5) and a second anti-reflection film (6), and the internal reflection structure is a continuous periodic grating (3) along the cavity; the distributed feedback gain chip is a continuous uniform grating distributed feedback gain medium (4); and the micro-ring resonant cavity is a micro-ring resonant cavity with a reflection function. A working method is also provided.

The invention discloses a special form grating-based color image hiding and multi-color dynamic display method, which comprises the following steps of: 1, constructing a grating substrate in image processing and compiling software, and generating a periodic grating; 2, extracting R, G and B components in the target color image, performing normalization processing on pixel values of the R, G and B components, and embedding the pixel values into phase parameters of the periodic grating; 3, the gratings generated by the R channel, the G channel and the B channel are superposed, and a grating containing a target color image is obtained; 4, constructing a key grating and superposing the key grating with the grating containing the target color image to obtain a grating for displaying target color image information; 5, adjusting the radial phase offset of the grating through a water ripple dynamic diffusion algorithm, and dynamically displaying a target color image; and 6, outputting the key grating, the grating containing the target color image and the target images of different colors disclosed in different time periods. According to the invention, high-secrecy and diversified dynamic display of target images with different tones is realized.

This invention discloses an optical waveguide module, relating to the field of optical device technology. It includes a substrate, an optical waveguide layer on top of the substrate, and a buffer layer with a continuously curved, wave-shaped design between the substrate and the waveguide layer. This invention forms a stress-relieving structure based on the wave-shaped buffer layer, substrate, and waveguide layer, achieving thermal expansion coefficient matching and bending stress dispersion between the substrate and the waveguide layer. Simultaneously, combined with various adhesion enhancement layers, it ensures the long-term stability of the multi-layer interface. Furthermore, the input coupling layer employs a composite design of a blazed grating and a subwavelength grating, significantly improving the coupling efficiency from visible light to near-infrared. The output coupling layer achieves wide field-of-view output through a gradient periodic grating, adapting to large viewing angle requirements. Additionally, it integrates a modulator and a graphene thermal conductive layer, simultaneously solving the problems of high-speed modulation and heat dissipation, significantly improving the optical performance, thermal stability, and mechanical reliability of the optical waveguide module.

Some implementations described herein may provide an optical device. The optical device may include an optical emitter and an optical element aligned to the optical emitter. The optical element may include an oxidation aperture, one or more distributed Bragg reflectors (DBRs) disposed on the oxidation aperture, and a stacked periodic grating structure disposed on the one or more DBRs. The stacked periodic grating structure may include a set of layers. The set of layers may include alternating layers of a first material and a second material. The stacked periodic grating structure may have a selected period, depth, and fill factor that are selected to achieve greater than a threshold level of optical field confinement in a transverse direction of an optical field emitted by the optical emitter.

The invention relates to the field of mechanical seal, in particular to a dynamic measurement method for a mechanical seal end face gap, which comprises the following steps of: S1, arranging periodic grating structures on non-sealing surfaces of a moving ring and a static ring of a mechanical seal; s2, in the operation process of the mechanical seal, collecting a dynamic image sequence of the periodic grating structure; s3, processing the obtained dynamic image sequence, extracting phase information of the periodic grating structure, and obtaining phase change data; s4, the relative displacement and the relative rotation angle between the sealing end faces of the movable ring and the static ring are calculated based on the phase change data; and S5, monitoring, early warning and evaluating the state of the mechanical seal. The invention provides a dynamic measurement method for a mechanical seal end face gap. According to the invention, non-stop and non-contact on-line detection of the mechanical seal end surface gap can be realized.

The application provides a metal periodic grating, an electron beam pulse width characterization device, a method and a microscope thereof. The device comprises a metal periodic grating, a light emitting electron gun, an ultrafast laser module and a camera, the ultrafast laser module comprises an ultrafast laser, a laser frequency conversion element and a delay device; the ultrafast laser module is used for converting laser generated by the ultrafast laser into pump laser and probe laser; and the light emitting electron gun is used for converting the probe laser into a pulsed electron beam. The application utilizes the metal periodic grating, and through the interaction between the pulsed electron beam and the grating near field induced by the pump laser when the pulsed electron beam passes through the grating surface, the electron beam is made to produce lateral broadening, and the pulse width of the pulsed electron beam is accurately characterized by using the broadening effect.

The application provides a wavelength-selective infrared emitter device controlled by ultrafast laser and voltage, which comprises a first phase change material layer, a dielectric layer, a second phase change material layer, a metal reflection layer, a silicon substrate and a conductive layer from top to bottom; by means of layered superposition design of nonvolatile phase change material and volatile phase change material, surface micro-nano structure control and optical resonant cavity control are spatially separated, so that structure reconstruction and cavity length conversion bear different spectral control tasks respectively, thereby breaking through the problem that the control freedom degree of single phase change material is limited; that is to say, the application adopts ultrafast laser to perform local phase change control on the first phase change material layer, so as to realize writing or erasing of a surface periodic grating structure, and by means of applying voltage, the second phase change material layer is subjected to phase transition, so as to adjust the equivalent optical cavity length of the Fabry-Perot cavity, and finally the spectral shaping ability and control flexibility are improved, and wavelength-selective control can be realized.

The invention discloses a SiC micro-nano chute grating and a method for processing the SiC micro-nano chute grating based on ion implantation induction and electric spark, and the method comprises the following steps: S1, processing by adopting a silicon carbide substrate, then depositing a Cr / SiO2 composite mask layer on the substrate, exposing, developing and etching to form a Cr / SiO2 composite mask structure with a periodic grid pattern; s2, introducing ions into the exposed SiC region as an n-type dopant by adopting a large-angle inclined ion implantation method to form a conductive modified region, and obtaining a locally modified silicon carbide substrate; and S3, adopting electric spark machining to stably form a single-pulse-scale directional corrosion pit in the target ion implantation region, and realizing linear scanning etching along the grid bar direction to obtain the SiC micro-nano chute grating with the nano-scale groove structure. According to the method, the problems of low processing efficiency, poor processing surface quality, poor morphology control and the like of the SiC substrate grating are solved, and directional induction etching with a specified side wall inclination angle is realized.

The invention relates to the technical field of spectrum detection, in particular to a Raman and fluorescence shared spectrum detection system and method.The system comprises an optical fiber convergent mirror, a Raman and fluorescence color separation piece, a double-optical-fiber assembly, a double-collimating-mirror assembly, a double-cycle grating, a double-convergent-mirror assembly, an image intensifier and an area array detector; and all the components are sequentially conducted according to a light path to form a complete structure. According to the method, after being converged and separated by laser excitation mixed light, the mixed light is transmitted and collimated by double optical paths, is synchronously dispersed by the double-cycle grating, is parallelly converged by the double convergent mirrors, and is finally synchronously acquired by the area array detector for photoelectric conversion. The system solves the problems of high cost, complicated operation, serious spectral interference and the like in the prior art, has the advantages of integration, synchronous detection, high resolution, low interference, light weight, miniaturization and high stability, and can be widely applied to multiple fields of deep space exploration, biomedicine and the like.

The invention provides a semiconductor laser and a preparation method thereof, and relates to the technical field of semiconductor lasers, the semiconductor laser comprises an epitaxial wafer, a ridge waveguide and periodic grating structures are arranged in a P-type limiting layer of the epitaxial wafer, and the periodic grating structures are distributed on the two sides of the ridge waveguide; the periodic grating structure comprises a plurality of ridge strips arranged in parallel and notch grooves located between the adjacent ridge strips, and the ridge strips are uniformly arranged along the length of the epitaxial wafer and are parallel to the ridge waveguide; according to the semiconductor laser, the periodic grating structures are arranged on the two sides of the ridge waveguide in the P-type limiting layer of the semiconductor laser, and each periodic grating structure is provided with a plurality of ridges and notches, so that the high-order lateral mode of the semiconductor laser is effectively regulated and controlled, and the periodic grating structures are simple in structure and low in cost. And the complexity of the photoetching process and the preparation difficulty of the semiconductor laser are reduced.

The invention discloses a diffraction grating for improving the diffraction efficiency of an extreme ultraviolet interference exposure mask and a manufacturing method thereof, and the method comprises the steps: preparing a periodic grating structure on a substrate, and obtaining a basic diffraction grating; and etching the substrate in a non-grating area by taking the periodic grating structure in the basic diffraction grating as a mask pattern to obtain a target diffraction grating with a periodic structure. According to the diffraction grating manufacturing method and the prepared diffraction grating, on the premise that the basic geometrical characteristics of the grating are kept unchanged, the composite optical interface is formed by periodically modulating the substrate structure, and due to the fact that the interaction between light and the structure can be enhanced through the composite optical interface, the energy coupling efficiency in the diffraction grating is improved; therefore, the diffraction efficiency of the extreme ultraviolet interference exposure mask is improved.

The application discloses an optical internal grating structure of glasses and a manufacturing method thereof. The method comprises the following steps: forming a polysilicon pattern with a triangular section on a silicon carbide substrate and performing surface oxidation; forming a silicon oxide layer on the surface of the polysilicon pattern by using a plasma enhanced atomic layer deposition process and back-etching to form a side wall structure with a smooth surface; etching the silicon carbide substrate until the side wall structure is etched and consumed; repeatedly performing surface oxidation treatment, forming a side wall structure and etching the silicon carbide substrate until the polysilicon pattern is etched and consumed; and forming a periodic grating structure on the silicon carbide substrate, so that the smooth surface of the side wall structure is transferred to the two side walls of the triangle of the grating structure through pattern transfer. The application can avoid thermal damage to the silicon carbide substrate, and can realize uniformity processing of the side wall and atomic-level flatness in a larger depth-width ratio during the preparation of the grating structure.

Compositions, systems, and methods for fabricating a grating are described herein. Grating structures can be formed to have evacuated periodic structures (EPSs) with alternating polymer rich regions and inert fluid rich regions. In an EPS process, a volume grating is formed after a holographic exposure process. This volume grating includes polymer rich regions (e.g. a polymer matrix) surrounding inert substance rich regions. The inert material rich regions are removed to produce high modulation surface relief gratings (SRGs) after the inert material is removed. The SRGs may include a polymer matrix surrounding air gaps.

This invention provides a silicon-based grating structure, fabrication method, and mid-infrared dual-color filter device for mid-infrared resonant filtering. The structure includes: a silicon-based substrate; an anti-reflection stacked structure disposed on the silicon-based substrate, the anti-reflection stacked structure being composed of a material with low absorption in the mid-infrared band; and a periodic grating layer disposed on the anti-reflection stack, the grating layer being composed of a silicon-based dielectric material with low light absorption in the mid-infrared band. The grating structure achieves a peak transmittance of >90% and an average transmittance of >85% in both the 3.0±0.1μm and 5.0±0.1μm bands by using diffraction coupling to excite guided mode resonance in conjunction with the anti-reflection stacked structure.

The invention relates to a Bragg grating device based on CO2 gas tuning and a preparation method, and belongs to the technical field of integrated photonics devices. The Bragg grating device comprises a single-mode fiber, a Bragg grating structure and a tuning medium; the single-mode optical fiber comprises a fiber core and a cladding; the Bragg grating structure is formed on the end face of the single-mode fiber; the Bragg grating structure comprises at least one supporting structure, a periodic grating structure fixed by the supporting structure and a hollow channel penetrating through the periodic grating structure; and the tuning medium is CO2 gas and is filled in the hollow channel. The micro grating with the built-in tunable gas cavity is integrally manufactured through two-photon polymerization 3D printing, and dynamic wavelength tuning with high precision, low loss, wide range and quick response of the device is realized by utilizing the low-loss refractive index regulation and control characteristic of CO2 in a specific infrared band.

The application belongs to the field of biochemical test, and particularly relates to a silver particle gold nanometer grating flexible substrate and a preparation method and application thereof. The polycarbonate layer in DVD or CD is used as a stamping mold, a three-dimensional periodic nanometer grating structure is prepared by stamping on a polyvinyl chloride (PVC) film, a gold layer is plated on the PVC, silver nanoparticles are uniformly decorated on the surface of the gold nanometer grating by using an interface self-assembly method, and the flexible substrate is prepared. The research results show that the electromagnetic field of the substrate is greatly enhanced, the uniform distribution of the silver nanoparticles and the periodic grating structure of the substrate enable the substrate to generate high-density and uniformly-distributed surface enhanced Raman scattering (SERS) hot spots, and the sensitivity and accuracy of detection are greatly improved. The application has the advantages of simple process, low cost and suitability for large-scale preparation, and provides a feasible idea for large-area preparation of a SERS substrate with high sensitivity, uniform signal and good stability.

The utility model provides a reticulated hinge loose-leaf and a book type certificate, the reticulated hinge loose-leaf comprises a first surface layer, a fabric layer and a second surface layer which are sequentially arranged from top to bottom, a plurality of reflective surfaces are hot-pressed at warp and weft overlapping positions on the surface of the fabric layer so as to present a latent image grid window with a preset shape in a preset area, and the reflective surfaces are reflective surfaces. Periodic gratings are formed at the positions, corresponding to the latent image grating windows, of the fabric layer, so that latent image patterns are shown on the surface of the fabric layer, and the first surface layer and the second surface layer are arranged on the two sides of the fabric layer in the thickness direction respectively to wrap the fabric layer. According to the reticulated hinge, the fabric layer is arranged as the center layer, and the latent image-text is formed at the overlapping position of the warp and the weft of the fabric layer, so that the reticulated hinge has excellent anti-counterfeiting performance and production convenience while having excellent physical properties such as tear resistance, flexibility and sewability, can be widely applied to the fields of various book type certificates, bills, packages and the like, and has wide application prospects. The application range is effectively widened, the practicability is enhanced, and cost reduction and efficiency improvement of enterprises are promoted.

This disclosure provides a dual parallel slit waveguide mode converter and its fabrication method. The device includes: a substrate, a buried oxide layer formed on the substrate, and a chip layer formed on the buried oxide layer. A waveguide structure is etched on the chip layer from one end to the other. The waveguide structure includes a periodic grating, a transition region, and an active modulation region connected sequentially. A dual parallel slit structure is formed in the active modulation region. The periodic grating is used to convert light into vertically coupled emission, and the transition region and active modulation region are used to convert the optical field mode in the waveguide structure into a dual-slit waveguide mode. This dual parallel slit waveguide mode converter has high coupling efficiency, low coupling loss, and small device size, making it easy to package.

An optical filter includes a carrier layer made of a first material. A periodic grating of posts is disposed on the carrier layer in a periodic pattern configured by characteristic dimensions. The posts are made of a second material. A layer made of a third material encompasses the periodic grating of posts and covers the carrier layer. The third material has a refractive index that is different from a refractive index of the second material. Characteristic dimensions of the periodic grating of posts are smaller than an interfering wavelength and are configured to selectively reflect light at the interfering wavelength on the periodic grating of posts.

The application discloses a kind of two-dimensional periodic grid sandwich plate structure acoustic vibration coupling system acoustic vibration characteristic analysis method, belong to structural acoustic analysis technical field.This method constructs the two-dimensional periodic grid sandwich plate structure acoustic vibration coupling system by upper and lower two plate structures, intermediate orthogonal grid rib and closed acoustic cavity, this acoustic vibration coupling system model has two-dimensional periodic cell structure, improved Fourier series is used to describe plate vibration displacement and acoustic cavity sound pressure, auxiliary function is introduced to ensure boundary continuity, based on energy method and Rayleigh-Ritz method, the Lagrangian function of coupling system is established, and the acoustic vibration characteristic prediction equation of acoustic vibration coupling system model is derived.The application is suitable for two-dimensional periodic grid sandwich plate structure periodic structure with arbitrary boundary condition and arbitrary cell number, with the advantages of high calculation efficiency, good convergence, strong model universality, etc., and can be used for vibration and noise reduction design of high-speed train carriage wallboard.

The invention discloses a moire-based power equipment temperature monitoring system and method. The moire-based power equipment temperature monitoring system comprises a temperature sensing device, an image preprocessing module, a moire feature extraction module and a temperature measurement and calculation module, a camera is used for detecting a moire visual mark which deforms along with the temperature change of the power equipment in the temperature sensing device; according to the invention, the temperature change of the power equipment is described as the change of the ratio of the projection frequency of the moire visual marked one-dimensional periodic grating calculated according to the moire characteristics on the imaging plane of the camera to the reference projection frequency, and the real-time temperature of the measured power equipment can be output.

The invention relates to the technical field of light-emitting devices, and discloses a perovskite electric control light-emitting device and a preparation method thereof. The light-emitting device comprises a one-dimensional photonic crystal cavity structure, a perovskite gain layer and a metal electrode layer. A first substrate is arranged on one side of the first dielectric layer; the second dielectric layer of the one-dimensional photonic crystal cavity structure is arranged on one side, far away from the first substrate, of the first dielectric layer; one side, far away from the first dielectric layer, of the second dielectric layer is provided with a grating forming area and a non-grating forming area; a one-dimensional periodic grating with a one-dimensional photonic crystal cavity structure is formed in the grating area; the first dielectric layer is combined with the two surfaces, in contact with the second dielectric layer and the first substrate, of the first dielectric layer to form a Fabry-Perot resonant cavity; the perovskite gain layer is arranged on one side, far away from the first dielectric layer, of the one-dimensional periodic grating; the metal electrode layer is arranged in the non-grating forming area. The perovskite light-emitting device solves the problems of carrier injection and light extraction efficiency of the perovskite light-emitting device.

The invention discloses a high-density ultra-weak grating dynamic sensing array sensor for an OPGW (Optical Fiber Composite Overhead Ground Wire) and an intelligent connector box and a sag monitoring method, and belongs to the technical field of on-line detection of high-voltage transmission lines, the high-density ultra-weak grating dynamic sensing array sensor comprises an optical fiber, and a plurality of periodic grating arrays are engraved on the optical fiber; the optical fiber is sequentially coated with a gradient refractive index cladding, a mechanical enhancement layer and an outer sheath. According to the invention, through the design of the ultra-weak grating array, the gradient refractive index cladding and the composite enhancement layer, the problems of low spatial resolution and poor strain transmission efficiency in the prior art are solved; and the TLS-ESPRIT high-precision demodulation and dynamic compensation model is combined on sag monitoring, so that the sag calculation precision of dynamic working condition monitoring is improved.