55 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.

The invention relates to an optical film with multiple periodic gratings, and belongs to the technical field of optical devices, the optical film comprises a grating arranged above a waveguide, and the side surface of the waveguide is provided with a photoelectric sensor; the grating comprises grating structures of multiple periods, the grating structure of each period corresponds to one incident angle range, and when incident light incident in the specific incident angle range is diffracted by the corresponding grating structure and then enters the waveguide, total reflection is met in the waveguide; the grating structures are arranged according to the period size, and any two adjacent grating structures meet the condition that the incident angle upper boundary corresponding to the grating structure with the large period is not smaller than the incident angle lower boundary corresponding to the grating structure with the small period; the photoelectric sensor is used for receiving diffracted light propagating in the waveguide. According to the optical film, diffraction light meeting total reflection in the waveguide is generated through the gratings with the corresponding periods for working wavelengths at different angles, the incident angle range is enlarged, and the effect that the incident working angle is continuous is achieved.

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.

The invention discloses a method for detecting surface defects of an electroformed metal plate, which relates to the field of electroformed metal plates and comprises the following steps: acquiring a grating stripe image of the electroformed metal plate under a periodic grating stripe projection condition and a surface color image under a uniform illumination condition; performing viewport transformation fusion on the grating stripe image and the surface color image to generate a composite detection image; pixel-level classification marking is carried out on different types of surface defect nodules in the composite detection image, and a marked composite detection image is generated; and carrying out surface defect detection model training, and carrying out surface defect detection on the to-be-detected electroformed metal plate by utilizing the trained model to obtain a corresponding defect probability graph. According to the method, multi-modal data are fused, a high-precision algorithm and a self-adaptive model are applied, post-processing is optimized, comprehensive high-precision defect detection on the surface of the electroformed metal plate is achieved, and the method is suitable for high-standard industrial detection scenes.

The present invention discloses a quantum dot laser with a low threshold and a preparation method thereof, which includes a quartz substrate, a silica periodic grating, a quantum dot layer, and a silica protective layer stacked in sequence. The quantum dot layer is composed of closely packed mercury selenide quantum dots with a diameter of 4.8 nm to 6.6 nm, mercury sulfide quantum dots with a diameter of 4 nm to 5.2 nm, quantum dots with a core / alloy / shell structure of mercury selenide / mercury cadmium selenide / cadmium selenide with an effective exciton diameter of 4.8 nm to 6.4 nm, or quantum dots with a core / alloy / shell structure of mercury sulfide / mercury cadmium sulfide / cadmium sulfide with an effective exciton diameter of 4 nm to 5 nm. The present invention realizes environmentally stable electron doping in quantum dots by controlling the size of the quantum dots, uses the doped quantum dots as the gain medium of the laser, and further realizes a low gain threshold, a low laser threshold, sustainable continuous laser output, and a designable output wavelength.

A two dimensional (2D) photonic crystal (PhC) structure includes a substrate and a periodic grating structure formed on the substrate. The periodic grating structure includes a plurality of gratings having a grating period, a. Each pair of adjacent gratings is separated by air. Each grating has a grating width, d, and includes a plurality of alternating layers of a first material and a second material. The first material corresponds to a high index material. The second material corresponds to a low index material. A ratio of a first refractive index of the first material to a second refractive index of the second material is greater than or equal to two. Each first material layer has a first thickness, t1. Each second material layer has a second thickness, t2. The 2D PhC structure has a structure refractive index at or near zero for a range of frequencies.

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 present application belongs to the technical field of glasses, and relates to a pair of smart glasses. The smart glasses comprise a glasses frame, an imaging optical module, an eye-tracking optical module and an optical waveguide module, wherein the glasses frame comprises rims and a connecting portion disposed on one side of each rim, a mounting cavity for the mounting of the imaging optical module and the eye-tracking optical module thereon being formed in the connecting portion; and the optical waveguide module is embedded in the rims, and comprises a waveguide substrate, and a first in-coupling and out-coupling grating group and a second in-coupling and out-coupling grating group, which are disposed on the waveguide substrate, at least some gratings in the first in-coupling and out-coupling grating group and the second in-coupling and out-coupling grating group being located on the same side of the waveguide substrate, and the gratings located on the same side of the waveguide substrate, namely, a first periodic grating and a second periodic grating, at least partially overlapping to form a composite grating. The smart glasses in the present application can independently couple in or out light rays of corresponding wavebands in the same region on the same side of a waveguide substrate by means of gratings of a composite grating, and thus effectively reduce the absolute area of the gratings, thereby facilitating a lightweight design and improving long-term wearing comfort.

The invention provides an integrated laser radar transmitting antenna based on a slit optical waveguide, which is based on a silicon-on-insulator chip with a certain top silicon thickness and a factory-replacing standard etching depth, and comprises a thick silicon substrate, a lower cladding, a top silicon slit optical waveguide structure, an upper cladding and the like. Periodic grating tooth structures are introduced to the silicon strips on the two sides of the slit, a signal light source passes through the device to generate emission light beams in the nearly vertical direction, the longitudinal scanning function of the light beams can be further achieved, and the scanning detection requirement of the laser radar is met. The weak-disturbance large-aperture optical antenna is constructed based on the single-layer slit optical waveguide structure, the known lowest beam divergence angle of the single-layer optical antenna structure is achieved, a new way is provided for emission aperture design and application of a laser radar, and the wide application prospect in the field of all-solid-state laser radars is achieved. And the blank of the ultra-large aperture integrated optical phased array laser radar transmitting antenna is filled.

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.

The present invention discloses a dual-frequency array-distributed orbital angular momentum mode generating device, which is processed by using laser processing technology to change the refractive index of a lithium niobate crystal. The processed lithium niobate crystal is divided into three regions; the first region is an unprocessed region, and the fundamental frequency light is converted into second harmonic light by using the birefringent phase matching of the lithium niobate crystal; the refractive index of the lithium niobate crystal is changed in the second region and the third region by using laser processing technology, and the fundamental frequency light and the second harmonic light are linearly diffracted; the second region is a fork-shaped grating array, which linearly diffracts the fundamental frequency light and the second harmonic light in the z direction and loads orbital angular momentum at non-zero orders; the third region is a periodic grating array, which linearly diffracts the fundamental frequency light and the second harmonic light in the x direction, so that the orbital angular momentum modes are distributed in an array. The present invention can simultaneously expand the fundamental wave and the second harmonic orbital angular momentum modes from one-dimensional distribution to two-dimensional, increasing the modulation channels of the optical field.

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 present invention discloses a multi-step periodic grating structure and a preparation method thereof, relating to the technical field of micro-displacement detection. It includes a periodic multi-step grating structure. Each period of the multi-step grating structure includes a substrate and a four-step grating structure. The four-step grating structures are all arranged on the substrate. According to the order from right to left within a single period, the four-step grating structures are respectively the first-step grating structure, the second-step grating structure, the third-step grating structure, and the fourth-step grating structure, which are layer structure arrays of three different heights. The present invention realizes the regulation and weakening of the zero-order diffracted light through structural improvement, so as to achieve the effect of improving the stability of the laser in the detection system. The multi-step periodic grating structure prepared by the corresponding preparation method has the function of weakening the zero-order light regulation, can realize a certain range of light intensity regulation, is convenient for preparation and integration, has a high diffraction efficiency, and can be applied to the field of integrated high-precision displacement detection.

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.

The utility model discloses a splicing displacement detection element, and relates to the field of encoders. The utility model discloses a splicable displacement detection element, which comprises a plurality of splicing units connected in sequence, and each splicing unit comprises a grating ruler with periodic grid scribed lines; the first connecting sheet is connected to one end of the grating ruler; the second connecting sheet is connected to the other end of the grating ruler; the adjacent splicing units are connected in an attached and aligned mode through the end faces of the first connecting pieces and the end faces of the second connecting pieces, and high-precision continuity of periodic grid scribed lines of the grid rulers of the adjacent splicing units is achieved. The grating rulers are mutually connected in a splicing mode, the problem that the length is limited is solved, meanwhile, the splicing precision is converted from the grating rulers to the connecting pieces, and the grating ruler has the advantages of being easy to transport and store, simple in process, economical, practical and suitable for multiple scenes.

The invention relates to the technical field of grating slow-wave systems, in particular to a terahertz grating slow-wave system which comprises a ridge waveguide ridge, a ridge waveguide shell, a first attenuator and a second attenuator, the ridge waveguide ridge is provided with a periodic grating, the period of the periodic grating is P, the depth of a grating groove is a, the width of the ridge waveguide ridge is d, and the width of the grating groove is a. The height of the ridge waveguide ridge is h, the thickness of the grating rib is W, and the ridge waveguide ridge is arranged at the middle position in the ridge waveguide shell; the number of the first attenuators is two, and the two first attenuators are arranged on the two sides of the ridge waveguide ridge respectively, located between the ridge waveguide ridge and the ridge waveguide shell and located at the position one third away from one side of the ridge waveguide shell. And the second attenuator is arranged at the last position of the periodic grating. The working frequency is continuous without breakpoints, the voltage is continuously adjusted, and the output frequency of the device is also continuously changed.

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.