141 results about "Metal grating" patented technology

The invention relates to the technical field of semiconductor lasers, in particular to an ultra-narrow linewidth wavelength-adjustable external cavity laser based on a planar metal grating, which comprises a gain chip, and the left end face and the right end face of the gain chip are respectively plated with a high reflection film and a first antireflection film; a planar metal grating waveguide is arranged on the right side of the gain chip, the right end face of the gain chip is aligned and attached to the left end face of the planar metal grating waveguide, and a second antireflection film and a third antireflection film are plated on the left end face and the right end face of the planar metal grating waveguide respectively; the planar metal grating waveguide comprises a grating waveguide substrate, a ridge optical waveguide is arranged on the upper portion of the grating waveguide substrate, an annular resonance optical waveguide is arranged on the front side of the ridge optical waveguide, a planar metal grating is arranged on the upper portion of the ridge optical waveguide, and a top covering layer is arranged on the upper portion of the planar metal grating. Through the centimeter-level metal grating and the low-loss coupling structure, light beam quality with 3dB line width less than 700Hz and M2 less than 0.9 is realized.

The invention relates to the technical field of optoelectronic devices, in particular to a laser based on two different gratings and a metal grating with a phase interval of lambda / 2, which comprises a gain chip, a gain chip optical waveguide, an optical waveguide substrate, an optical waveguide, an annular resonant optical waveguide and a metal BRAGG reflecting grating. A unique outer cavity structure is adopted, a traditional interlayer semiconductor grating is abandoned, a top metal grating is adopted, a traditional DFB sandwich type secondary epitaxy manufacturing process is greatly simplified and avoided, the production cost is reduced, particularly, the metal grating is divided into two parts with similar but different grating constants, and the phase positions of the two gratings are pulled by lambda / 2, so that the performance of the DFB is improved. According to the design, the side mode rejection ratio (SMSR) of laser beams can be effectively improved, the laser line width is compressed, a guarantee is provided for stable work of the laser in a high-performance application scene, and the grating reflection efficiency is effectively improved by combining a'mouth-to-mouth 'coupling butt joint mode of the gain chip and the optical waveguide substrate.

The invention relates to a laminated staggered sub-wavelength polarization grating structure and a preparation method thereof, through staggered arrangement of a first metal grating layer and a second metal grating layer, transmission of polarized light of a transverse electric field can be effectively inhibited, and the extinction ratio is remarkably improved. Through the substrate, the first dielectric layer, the second dielectric layer, the first metal grating layer, the third dielectric layer and the second metal grating layer which are sequentially arranged from bottom to top, the whole device obtains a higher extinction ratio while keeping high transmittance, the overall structure is simple, the processing difficulty and cost are reduced, and the production efficiency is improved. And the number of the used dielectric layers and metal layers is small, the thickness requirement is low, and therefore it is ensured that the cost is controllable.

The invention discloses a polarization sensitive type broadband absorber based on metal-medium stacking, and relates to the technical field of micro-nano photonic devices and infrared detection. The absorber sequentially comprises a bottom-layer high-loss metal reflecting layer, a multi-layer stacked composite dielectric cavity structure and a top-layer sub-wavelength metal grating from bottom to top, according to impedance matching and interference resonance theories, a broadband absorption substrate is constructed through a multi-layer film structure at the bottom, and light energy is converted into heat energy by utilizing the high loss characteristic of bottom layer metal; plasmon resonance is excited through the top metal grating, the coupling efficiency of TM polarized light is enhanced, and TE polarized light is cut off; the above structural design successfully realizes efficient broadband absorption and high polarization extinction ratio in an infrared band. The structure is simple in design, is compatible with a CMOS technology, and has excellent wide-angle stability. And meanwhile, polarization screening can be realized without an external polaroid, and miniaturization and integration of an infrared detection system are facilitated.

The invention relates to the technical field of ocean observation, in particular to a hydrate reservoir information in-situ monitoring device. Comprising a monitoring box body; a metal grating plate is arranged at the bottom of the monitoring box body, and hydrate reservoir sediments can enter the monitoring box body through grating holes in the metal grating plate; a dissolved oxygen sensor, a pH sensor, a Raman probe rod and a resistivity probe rod are sequentially arranged in the monitoring box body from top to bottom, and a water tank camera is arranged on the side wall of the monitoring box body; a plurality of annular electrodes are arranged on the resistivity feeler lever in the circumferential direction of the feeler lever at intervals, and each annular electrode is connected with an annular electrode distance adjusting mechanism and an annular electrode aperture adjusting mechanism. And in-situ monitoring of the hydrate reservoir can be realized.

The invention discloses a vertical plasmon waveguide device structure capable of being coupled by an optical fiber and a preparation method of the vertical plasmon waveguide device structure, and belongs to the technical field of integrated optoelectronics, and the structure is composed of a pair of metal gratings and a vertical metal-medium-metal plasmon waveguide. The structure comprises a silicon substrate layer, a lower metal layer, a dielectric layer and an upper metal layer which are arranged from bottom to top and is divided into a grating area and a waveguide area, the grating area comprises a dielectric grating area and a metal grating layer, and the waveguide structure comprises the lower metal layer, the dielectric layer and the upper metal layer. According to the design of the invention, the limitation of mass production caused by an overlay process of a mode converter between heterogeneous integrated waveguides is avoided, and the preparation robustness of the device is improved. The optical insertion loss caused by the roughness of the side wall of the waveguide is improved in a metal deposition-dielectric spin coating-metal deposition mode, and the dielectric layer can be replaced to realize multiple device functions.

The invention discloses a backside illuminated image sensing structure, a sensor and a preparation method, and belongs to the field of semiconductors, the backside of a substrate is thinned to form a laminated photosensitive structure through a deposition process, a deep trench isolation structure is prepared on the laminated photosensitive structure, a first section of metal grating is prepared, and ions of VA group elements are injected to form a second section of metal grating; an inclined reinforced doping belt is formed; then preparing a second section of metal grating to obtain a complete metal grating, obtaining a back-illuminated image sensing structure, and then performing the processes of activation, preparation of a filter layer and the like to obtain a complete back-illuminated image sensor; according to the invention, the stacked photosensitive structure and the reinforced doping band are combined, so that the crosstalk effect is greatly reduced while the problem of doping damage to the substrate is solved, and the performance of the image sensor is improved.

The safety barricade system for use with metal grate flooring may include a stanchion, one or more retainers, and a warning light. The bottom of the stanchion may detachably couple to a metal grate includes a floor and may be held in place by the one or more retainers. The stanchion may be vertically-oriented such that the top of the stanchion is elevated above the metal grate, placing the top of the stanchion within the cone of vision of a user. The stanchions may be used individually to designate a position. The stanchions may be used in groups and in conjunction with caution tape to designate a boundary. The warning light located at the top of the stanchion may be illuminated to increase the visual awareness of the stanchion.

The invention relates to the technical field of optoelectronic devices, in particular to a laser based on two different gratings and a metal grating with a phase interval of lambda / 2, which comprises a gain chip, a gain chip optical waveguide, an optical waveguide substrate, an optical waveguide, an annular resonant optical waveguide and a metal BRAGG reflecting grating. A unique outer cavity structure is adopted, a traditional interlayer semiconductor grating is abandoned, a top metal grating is adopted, a traditional DFB sandwich type secondary epitaxy manufacturing process is greatly simplified and avoided, the production cost is reduced, particularly, the metal grating is divided into two parts with similar but different grating constants, and the phase positions of the two gratings are pulled by lambda / 2, so that the performance of the DFB is improved. According to the design, the side mode rejection ratio (SMSR) of laser beams can be effectively improved, the laser line width is compressed, a guarantee is provided for stable work of the laser in a high-performance application scene, and the grating reflection efficiency is effectively improved by combining a'mouth-to-mouth 'coupling butt joint mode of the gain chip and the optical waveguide substrate.

The present application provides a method for etching a hard mask for a backside metal grid. The method forms a metal grid pattern by etching a second hard mask layer on the backside of a substrate. The method then uses the second hard mask layer as a mask to perform a main etching on the first hard mask layer in a carbon-rich environment, and then performs a secondary etching on the first hard mask layer in a fluorine-rich environment. The method opens the first hard mask layer by performing a main etching on the first hard mask layer in a carbon-rich environment while reducing the oxygen supply, causing a certain amount of byproducts to accumulate on the sidewalls and bottom wall near the bottom of the trench. The method then performs a secondary etching on the first hard mask layer in a fluorine-rich environment to trim the profile of the grid-shaped trench and remove excess byproducts attached to the sidewalls and bottom wall of the trench. This improves the morphology of the grid-shaped trench in the second hard mask layer and the uniformity of the thickness of the grid-shaped trench sidewalls, thereby improving the uniformity of the critical dimensions of the metal grid formed by subsequently etching the metal material layer.

The invention relates to the field of photoelectric detection, and discloses a photoelectric detector based on a grating structure and a photoelectric detection method.The photoelectric detector comprises a substrate layer and a photoelectric material layer, and the photoelectric material layer comprises a metal grating structure, a first electrode, a second electrode, a first photoelectric confinement material and a second photoelectric confinement material; the metal grating structure comprises a first metal grating and a second metal grating, the first photoelectric confinement material and the second photoelectric confinement material are connected, and a depletion junction region is formed at an interface; the first metal grating and the second metal grating are symmetrically arranged on two sides of the depletion junction region and are used for exciting a plasmon mode to form a local light field; the first electrode is connected with the first photoelectric confinement material, the second electrode is connected with the second photoelectric confinement material, and the first electrode and the second electrode are used for extracting photon-generated carriers. According to the technical scheme provided by the invention, the separation efficiency of photon-generated carriers and the response performance of the photoelectric detector can be improved.

A high-strength protection grid is produced with a plurality of metal wires which are intercalated with metal ropes. The metal wires are interlaced with each other in interlacing portions, or are twisted in twists around the ropes in twisting portions. The interlacings between the wires and the twists of the wires with the ropes define the mesh of the grid. The interlacings and the twists are each unidirectional. The ropes have an external diameter which is greater than the wires and greater than 8 mm, preferably between 9 and 12 mm, even more preferably approximately of 10 mm. The grid is produced with a machine which is provided for the passage of ropes with such an increased diameter with respect to the ropes of the protection grids of the prior art.

The utility model discloses a municipal drainage filtering mechanism, and relates to the technical field of municipal administration. The municipal drainage filtering mechanism comprises a metal main body round frame, a filtering and collecting barrel and an anti-odor-returning structure, a connecting barrel is fixedly installed at the bottom of the metal main body round frame, a metal grating disc is installed on the metal main body round frame in a clamped mode, the filtering and collecting barrel is arranged on the metal main body round frame, and the filtering and collecting barrel is located at the bottom of the metal grating disc; a positioning inserting block is fixedly installed on the outer wall of the filtering and collecting barrel, the anti-odor-returning structure is arranged on the connecting barrel and composed of an internal thread connecting barrel and hollow funnel-shaped rubber, and connecting assemblies are arranged on the internal thread connecting barrel and the hollow funnel-shaped rubber. According to the municipal drainage filtering mechanism, discharged water can be filtered for several times, the filtering effect of the municipal drainage filtering mechanism is better, the filtering material collecting barrel is not prone to being blocked due to the shape arrangement of the filtering material collecting barrel, meanwhile, the situation of odor returning can be prevented, and discomfort caused by odor returning at the drainage position to pedestrians passing by is avoided.

The utility model provides a board arrangement structure capable of improving wiring isolation and a circuit board. The board arrangement structure for improving the wiring isolation comprises a dielectric layer, two floors which are respectively fixed on the bottom surface of the dielectric layer and are separated from each other, and two microstrip lines which are fixed on the top surface of the dielectric layer at an interval and are coupled with each other, the first metal ground hole and the second metal ground hole penetrate from the bottom surface of the dielectric layer to the top surface of the dielectric layer and are mutually spaced; the first metal layer is fixed on the top surface of the dielectric layer and is arranged opposite to one of the floors; the second metal layer is fixed on the top surface of the dielectric layer and is arranged opposite to the other floor; and the energy consumption device is connected with the first metal layer and the second metal layer. Compared with a metal paving mode, the plate arrangement structure for improving the wiring isolation degree has a better isolation effect, and compared with a space metal grating mode, the plate arrangement structure for improving the wiring isolation degree does not need to increase working procedures and is lower in cost.

The application discloses a kind of phase electromagnetic metasurface design methods based on two-phase method, mainly solve the problem of electromagnetic metasurface structure complexity when existing technology electromagnetic metasurface is simultaneously regulated in amplitude phase.It is implementation scheme: initialization electromagnetic metasurface parameter;Electromagnetic metasurface unit required by two-phase method is calculated phase matrix;Design the electromagnetic metasurface unit including metal grating layer, two layers of dielectric layer and metal patch, and draw the phase table of the electromagnetic metasurface unit;According to the required phase of each unit of electromagnetic metasurface and the phase table of electromagnetic metasurface unit, the state of each unit of electromagnetic metasurface is adjusted to obtain adjusted electromagnetic metasurface;Feed horn is placed above adjusted electromagnetic metasurface, and radio frequency signal is added to feed horn, to generate required beam, complete phase electromagnetic metasurface design.The application can reduce the complexity of electromagnetic metasurface structure, improve the beam design capability of electromagnetic metasurface, and can be used for wireless transmission, communication system.

An equipotential safety device comprises a metallic grate sized and configured to be set upon the floor of a bucket of a bucket truck. The grate is in electrical communication with an electrical grounding source.

The embodiment of the present application discloses a kind of transmission type terahertz absorption structure and preparation method thereof.Transmission type terahertz absorption structure includes at least one transmission type terahertz absorption composite film layer, transmission type terahertz absorption composite film layer includes substrate and the metal grating layer, insulating layer and graphene layer that are sequentially stacked in substrate side;Wherein metal grating layer and graphene layer are electrically connected with external power supply.The technical scheme of the embodiment of the present application is based on electromagnetic wave theory and the electrical properties of graphene, by additional voltage control Fermi level of graphene, adjust the absorption of absorption structure to terahertz, make the terahertz wave that pass through the present absorption structure have different intensity information under the influence of external voltage, play the role of switch, and have the advantages of active regulation, real-time control, accurate control, suitable for terahertz spectrum imaging analysis, single-pixel imaging and spectrum measurement etc.

The utility model aims at solving the problem of low filtering efficiency caused by the low melting point of asphalt blocking the filter screen, provides a device for filtering ring asphalt, belongs to the technical field of filter device. The device for filtering ring asphalt comprises: a metal filter container, a metal grid support plate and a metal filter screen. The bottom of the metal filter container is provided with a drain; the metal grid support plate is clamped and fixed in the metal filter container; the metal filter screen is laid on the upper surface of the metal grid support plate; wherein, the metal grid support plate provides cold energy to the metal filter screen in contact with it during use. In the utility model, the metal grid support plate provides cold energy to the metal filter screen in contact with it, especially when the wastewater temperature is relatively high or the use environment temperature is relatively high, a local low-temperature cold environment is formed, so that the deposited asphalt particles can maintain the particle form, the softening phenomenon of asphalt is delayed, and the use efficiency of the metal filter screen is ensured.

The invention discloses an efficient dust removal device for crushing and sorting retired fan blades, which comprises a pretreatment unit, a first purification unit and a second purification unit, the pretreatment unit comprises a device body, a metal grating, a fiber interception net and an induced draft fan; the first purification unit comprises a bag-type dust collector, a dust concentration sensor, a pulse injection device and a screw conveyor, the dust concentration sensor detects the thickness of a dust layer on the surface of the bag-type dust collector, the discharge end of the scraper conveyor is communicated with a dust storage tank, the second purification unit comprises an adsorption tower, a scattering dust instrument and a VOCs detector, and the adsorption tower is communicated with the dust storage tank. The scattering dust meter and the VOCs detector are arranged on a pipeline at an air outlet of the adsorption tower, and the control mechanism comprises an audible and visual alarm, a controller and a central control screen. The high-efficiency dust removal device for crushing and sorting the retired fan blade has the advantages of directionally intercepting fibers, dynamically adapting the dust yield and cooperatively purifying multiphase pollutants.

The invention relates to the technical field of gratings, in particular to a metal wire grating structure and a preparation method thereof.The metal wire grating structure comprises a substrate, a reflecting layer, a transparent dielectric layer and a metal grating layer which are sequentially stacked from bottom to top; wherein the thickness of the metal grating layer is not greater than 30nm; when incident light irradiates the metal wire grating structure from the side, away from the transparent dielectric layer, of the metal grating layer, part of the incident light is directly reflected by the metal grating layer to form a first path of reflected light, and the remaining part of the incident light enters the transparent dielectric layer through intervals between the metal wires. And after being reflected by the reflecting layer, the first path of reflected light is emitted out again through the transparent dielectric layer and the interval between the metal wires to form a second path of reflected light, and the phase difference between the first path of reflected light and the second path of reflected light is odd times of pi. According to the invention, the anti-pollution capability and the anti-wear capability of the grating are improved at least on the premise of ensuring that the grating has relatively high diffraction efficiency.

The invention relates to the technical field of measuring switches, and discloses a measuring switch with an overload protection structure, which comprises a body, wiring ports are arranged at two ends of the body, a knob switch is arranged on one side of the body, and a conductive mechanism, a circuit board and a measuring module are mounted in the body. A data processing module, a control module and a communication module are integrated on the circuit board, the conductive mechanism is electrically connected with the circuit board, the measuring module is in communication connection with the circuit board, and the measuring module is used for monitoring the current intensity of the wire outlet end and feeding data back to the circuit board through the communication module. The front blocking piece is arranged in the power transmission module, the lower end of the front blocking piece is bent towards one side of the rear blocking piece to form the first bent part, and the distance between the front blocking piece and the rear blocking piece is shortened through the first bent part, so that when a circuit is short-circuited, the distance between the two blocking pieces is relatively closer, and the phase voltage difference between the two blocking pieces is smaller; and the generated electric arc is relatively weak, and the efficiency of cooling and eliminating the electric arc through the metal grating is higher.

The utility model discloses an assembly type hanging metal grating ceiling structure which comprises a hanging rod, the top end of the hanging rod is fixedly connected with the top face of the structure, the tail end of the hanging rod is fixedly connected with a U-shaped keel, the section of the U-shaped keel is bent to form a U-shaped keel sliding groove, a sliding block is arranged in the U-shaped keel sliding groove, and the U-shaped keel sliding groove is fixedly connected with the hanging rod. The lower end face of the sliding block is connected with a C-shaped keel through a first bolt, the lower portion of the C-shaped keel is connected with a metal grating through a hanging piece, the section of the metal grating is bent to form a metal grating sliding groove, and the metal grating sliding groove is used for being connected with the hanging piece in a clamped mode. Through the optimized and improved design of the product, the fabricated suspended metal grating suspended ceiling structure not only has good safety performance, is simple to construct and adjustable, but also does not influence the attractive appearance, so that the purposes of realizing quick assembly, improving the construction efficiency and achieving efficient construction are achieved.

The application discloses a kind of methods for realizing cylindrical grating coherent Smith-Purcell radiation enhancement, Smith-Purcell radiation is a kind of incoherent spontaneous radiation, the power of radiation is very low, not easy to detect and application, to realize high intensity Smith-Purcell radiation, the application proposes based on quasi-continuous domain bound state enhancement method.First, the electron bunch string is generated using the electron gun;Then, make the electron bunch string pass through the surface of cylindrical metal grating, the repetition frequency of electron bunch string is used as the resonance frequency of quasi-continuous domain bound state, to realize the enhancement of coherent Smith-Purcell super-radiation, and finally the electron enters the collecting electrode.The cylindrical grating coherent Smith-Purcell radiation enhancement method proposed in the application is simple to operate, and has obvious effect, easy integration, low cost and other characteristics.

This invention relates to the field of optoelectronic device technology, and in particular to a laser based on a top-surface metal layer and a planar metal grating, and its fabrication method. The laser comprises a gain chip, an optical waveguide, a planar metal grating, a capping layer, and a metal layer. The planar metal grating fabricated using an electronic evaporation deposition process replaces the traditional complex three-dimensional etching, significantly improving the controllable precision and flatness of the grating structure. It eliminates the InP secondary epitaxial process, simplifying the overall process flow, reducing production costs, and simultaneously improving product performance consistency and yield. It also significantly improves reflection filtering efficiency, ensures the purity of the Bragg reflection spectrum, and helps achieve narrow linewidth performance in lasers. The capping layer above the planar metal grating effectively solves the problem of lattice mismatch in semiconductor secondary epitaxy, and can also confine diffracted light, reducing light energy leakage. The external cavity structure design increases the degree of freedom.

The invention belongs to the technical field of optoelectronic devices, and particularly relates to a planar metal grating laser based on two different gratings and with a phase interval of lambda / 2, which comprises a gain chip, a gain chip optical waveguide, an optical waveguide substrate, a back optical waveguide, an annular resonance optical waveguide and a planar metal grating. A unique outer cavity structure is adopted, a traditional interlayer semiconductor grating is replaced by two metal plane gratings with similar grating constants and a phase difference of lambda / 2, the advantages that the plane metal gratings do not need to be etched and are smoother and more regular are utilized, and a'mouth-to-mouth 'coupling butt joint mode of a gain chip and an optical waveguide substrate is combined; the covering layer grows on the plane metal grating, and the high-reflection HR film is plated on the covering layer, so that the grating reflection efficiency is effectively improved, the optical energy loss of the optical waveguide is reduced, meanwhile, secondary epitaxy is omitted, the process is simplified, and the cost is reduced.

The application discloses an ultra-wideband polarization converter metasurface for converging lenses and spatial imaging. The cell of the metasurface is composed of two metal gratings, two pairs of L-shaped metal patches and two dielectric plates. The metasurface of the application works in the range of 0.5 to 1.8 THz, the transmission coefficient is greater than 0.87, the relative bandwidth reaches 113%, the polarization conversion rate remains close to 100%, and the phase covers 360°. The metasurface has the advantages of simple structure, small size, high bandwidth, good polarization characteristics, easy integration, low loss and simple preparation process. The metasurface combines the changes of geometric phase and amplitude, which can not only realize two-dimensional focusing lenses by using phase changes, but also realize spatial imaging functions by using amplitude changes. The research results show that the metasurface provides a new way for the flexibility of terahertz wave polarization and phase manipulation, and opens up a new way for the dynamic operation of terahertz wave fronts.

The invention relates to the technical field of optics, and discloses a broadband circular polarization terahertz source and application thereof, and the broadband circular polarization terahertz source comprises a free electron beam moving along a predetermined direction and a stacked bianisotropic metasurface located above the free electron beam; wherein the stacked bianisotropic metasurface comprises at least two layers of metal gratings which form a stacked structure; the at least one dielectric plate is used for separating the metal grating; wherein the number of layers of the dielectric plate is one less than that of the metal grating; and the metal grating and the dielectric plate form a periodic structure together, and are used for coupling evanescent wave energy of the free electron beam into multiple resonant modes so as to excite broadband circular polarization terahertz radiation. According to the technical scheme provided by the invention, the tunable and compact terahertz source with high power output can be realized.

The embodiment of the invention provides a plasmon waveguide structure and a refractive index sensor, and the plasmon waveguide structure comprises a metal substrate layer; a multi-period composite metal grating layer; the dielectric layer is arranged between the metal substrate layer and the multi-period composite metal grating layer; wherein the multi-period composite metal grating layer is composed of nano-metal supercell structures which are periodically arranged in the direction, and each nano-metal supercell structure is formed by periodically arranging at least two metal structures with different grating periods in the direction according to a preset grating interval; and the structures are alternately arranged in the direction at preset periodic intervals. According to the invention, decoupling and flexible regulation and control of resonance position and intensity can be realized based on a plurality of independent resonant cavities with spatial separation provided by the multi-period composite metal grating layer.

The application provides a method for exciting interband plasmons of double-layer graphene and a prepared device, and belongs to the technical field of optical devices, and comprises the following steps: sequentially laminating a third insulating layer, double-layer graphene and a second insulating layer to form a vertical heterojunction, transferring the vertical heterojunction to a substrate on which a first insulating layer is grown, obtaining a clean initial device substrate through heating separation and solvent cleaning, then preparing a nanoscale metal grating layer on the vertical heterojunction surface of the initial device substrate to form a device intermediate body, and preparing electrodes on the left and right sides of the device intermediate body, so that the electrodes are electrically connected with the double-layer graphene, an electrical regulation channel of the Fermi surface of the double-layer graphene is constructed, and a complete device for exciting interband plasmons is obtained. The nanoscale metal grating array can effectively excite interband plasmons of double-layer graphene, significantly improve the light-plasmon coupling efficiency and realize energy regulation of interband plasmons.

The invention relates to the technical field of optical detection, in particular to a buried structure detection device based on laser-induced ultrasonic waves, which comprises a laser, a light splitting element, a light modulation module, a beam combining element, a light sensitive element and a lock-in amplifier, and is characterized in that pulse laser generated by the laser is divided into pump light and detection light; after the light modulation module periodically modulates the pump light, the pump light and the probe light are confocal on the surface of a to-be-detected sample through the beam combining element; the pump light excites ultrasonic waves, and the ultrasonic waves are reflected by the metal grating in the sample to form a sound wave induction interface grating; the detection light is received by the photosensitive element after being diffracted and is converted into an electric signal; a lock-in amplifier extracts a synchronized diffracted signal from the signal using the modulation frequency. The method can effectively penetrate through the opaque material layer to detect the completely buried alignment mark, overcomes the limitation of the traditional optics and the existing laser ultrasonic technology, and improves the detection precision and reliability of the deep structure.