439 results about "Sub wavelength" patented technology

A metalens for focusing light is described. The metalens includes a library of elements for varying the propagating phase of the focusing light over at least a 2π radians range, where the library of elements is arranged in a sub-wavelength pattern that defines spacings between the elements. Each spacing exhibiting temperature-dependent spacing changes within a temperature range and each element in the library of elements includes: a refractive index exhibiting a temperature-dependency within the temperature range, a shape exhibiting a temperature-dependency within the temperature range, and a size exhibiting a temperature-dependency within the temperature range. The metalens also includes a phase profile defined by a combination of the refractive index, shape, and size of each element in the library, and the sub-wavelength pattern of the library of elements. The metalens also includes a focal length defined by the phase profile, the focal length exhibiting a temperature-dependency within the temperature range.

The present disclosure provides an optical component, which may be a metasurface grating, including (a) a substrate; and (b) an array of subwavelength-spaced phase-shifting elements, which are tessellated on the substrate to produce, when illuminated with a polarized incident light, a diffracted light beam with a distinct polarization state for each of a finite number of diffraction orders, wherein the finite number is 2 or more.

The invention provides a deep frequency shift super-resolution microscopic imaging chip and a deep frequency shift super-resolution microscopic imaging system for omni-directional ultra-high wave vector illumination, and belongs to the technical field of optical super-resolution microscopy. The chip comprises a substrate plated with an adhesion layer and multiple layers of films on the adhesion layer, and sub-wavelength-scale circular ring gratings are engraved on the substrate and the adhesion layer; exciting light enters the circular ring grating through the substrate, and evanescent waves of ultrahigh wave vectors in all directions are generated through the circular ring grating. The evanescent waves are coupled to the upper surface through the multi-layer thin film to excite surface plasmons with ultrahigh transverse wave vectors in the corresponding direction, and the surface plasmons are used for carrying out all-directional ultrahigh wave vector illumination and deep frequency shift super-resolution microscopic imaging on a sample placed on the upper surface of the multi-layer thin film. The system comprises an excitation module, a deep frequency shift super-resolution microscopic imaging chip for omni-directional ultra-high wave vector illumination, an imaging module and an excitation control and image acquisition module. According to the invention, omni-directional ultra-high resolution imaging of a complex fine structure sample can be realized, so that application requirements in related fields can be met.

The invention provides a metasurface structure and method for realizing transverse polarization focusing light splitting, and the metasurface structure comprises a substrate and a surface structure which is disposed on the substrate. The surface structure is composed of a plurality of sub-wavelength structure units which are arranged in a concentric circular ring mode. The sub-wavelength structure unit performs polarization-independent focusing of an incident beam through transmission phase regulation and control, and performs polarization-dependent light splitting of the incident beam through geometric phase regulation and control. The point diffraction plate can realize light beam splitting and focusing functions related to polarization, has the advantages of being simple in structure and high in integration level, solves the technical problems that an existing point diffraction plate does not support synchronous phase-shifting interference measurement and the contrast ratio of interference fringes is low, and enables the contrast ratio of the interference fringes of point diffraction interference measurement to be higher, the resolving precision to be higher and the resolving speed to be higher.

A metasurface structure including an array of sub-wavelength structures including a phase change material (PCM), encoded with different holographic images based on different phases of the PCM, the different phases including a first phase and a second phase. Phase transition between the first phase and the second phase occurs when the metasurface structure is thermally tuned. Each sub-wavelength structure in the array has a distinctive phase difference between the first phase and the second phase of the PCM.

The invention provides an acoustic vortex tunneling transmission method based on topology pairing metasurfaces, and the method comprises the steps: respectively arranging an absorption type metasurface and an emission type metasurface which have opposite topological charges at an inlet and an outlet of a tunneling channel, forming a pair of topology pair TPMs structures, and forming a vortex tunneling system together with a sub-wavelength channel; mode conversion between vortex waves and plane waves is achieved through multi-period fan-shaped grooves etched in the angular direction and the radial direction, and the transmission efficiency is enhanced through Fabry-Perot resonance in a sub-wavelength channel. When the length of the tunneling channel meets specific conditions, periodical adjustment of transmissivity and perfect tunneling can be achieved, and the tunneling structure has high OAM mode coupling and transmission efficiency while guaranteeing the compact structure and low material cost. The metasurface designed by the invention supports diversified acoustic vortex tunneling transmission along a straight line and a curve, and shows excellent flexibility and stability.

The invention specifically discloses a circular polarization selection type wavefront shaping device of a terahertz wave band and a use method, and relates to the technical field of terahertz application. The device comprises a dielectric substrate layer and a dielectric cylinder microstructure layer, wherein the dielectric cylinder microstructure layer is arranged at the top of the dielectric substrate layer; the dielectric cylinder microstructure layer is composed of supramolecular dielectric cylinders arranged in an array mode, and each supramolecular dielectric cylinder is composed of a first dielectric cylinder superatom and a second dielectric cylinder superatom which are different in size. The first dielectric cylinder superatoms and the second dielectric cylinder superatoms are of sub-wavelength structures, and the distances between the dielectric cylinder superatoms in the adjacent rows and between the dielectric cylinder superatoms in the adjacent columns are smaller than the wavelength of incident terahertz waves. The first dielectric cylinder super atoms and the second dielectric cylinder super atoms and the corresponding substrates form geometric phase units respectively, and the dielectric cylinder rotation angles of the first dielectric cylinder super atoms and the second dielectric cylinder super atoms change along with coordinates. The device realizes selection and wavefront shaping of right-handed or left-handed circularly polarized terahertz waves, and can be widely applied to the fields of terahertz polarization spectrum measurement and imaging.

The invention belongs to the technical field of metal crack detection, and discloses a metal microcrack ultrasonic detection method, which comprises the following modules: an ultrahigh frequency composite array probe with a center frequency dynamic adjustable range of 5-50 MHz; the dual-mode excitation and receiving module is used for independently generating a pulse reflection mode excitation signal and a diffraction mode chirp frequency modulation signal; the phase-controlled synthetic aperture dynamic focusing module is used for realizing + / -60-degree deflection and sub-wavelength level focusing of acoustic beams; the nonlinear harmonic enhancement module is used for exciting a crack nonlinear effect by superposing 1-2MHz fundamental waves; and a time-space-frequency three-domain data fusion module. According to the method, signal-to-noise ratio collapse caused by the diffraction effect in a traditional method is overcome, more importantly, the system has low-frequency penetrability and high-frequency resolution at the same time due to 80%-120% of broadband coverage of chirp frequency modulation signals, the diffraction signal gain is increased by 20 dB or above, a near-surface blind area is compressed to be within 0.2 mm, and the system can be applied to the field of radar imaging. And the core pain point of missing detection of the near-surface microcracks of the thin-wall component is solved.

The invention discloses an evanescent coupling type germanium-silicon photoelectric detector based on a sub-wavelength grating, and belongs to the technical field of photoelectric detection. The germanium-silicon photoelectric detector comprises a silicon slab waveguide layer, a ridge waveguide layer, a germanium absorption region, an upper cladding and an electrode, the ridge waveguide layer comprises a first ridge waveguide area, a second ridge waveguide area, a third ridge waveguide area and a fourth ridge waveguide area, and the fourth ridge waveguide area is used for receiving optical signals and transmitting the optical signals to the third ridge waveguide area and the germanium absorption area; the waveguide of the third ridge waveguide region adopts a sub-wavelength grating with a gradually-changed size to regulate and control the coupling characteristic of light, so that the light can be gradually received by the first germanium absorption region and the second germanium absorption region on the two sides in the propagation process, and absorption light fields can be uniformly distributed in the germanium absorption regions. Signal distortion caused by the fact that the front end of germanium enters a saturation state under high-power incidence can be effectively avoided. The invention further provides a preparation method of the germanium-silicon photoelectric detector, the preparation method is compatible with the COMS technology, and the process complexity and the production cost are reduced.

The invention discloses a broadband full-Stokes polarization imaging device based on non-orthogonal four-channel polarization beam splitting, which comprises a dielectric substrate, a non-orthogonal polarization beam splitting metasurface and a focal plane detection array, and is characterized in that the non-orthogonal polarization beam splitting metasurface is composed of a plurality of sub-wavelength unit structures; the sub-wavelength unit structure is a single-layer anisotropic medium nano-column array and is configured to perform intrinsic-loss-free non-orthogonal four-channel beam splitting on incident light and form four spatially separated focuses on the same focal plane, and polarization states corresponding to the four channels form a regular tetrahedron measurement base on a Poincare sphere; therefore, full Stokes parameter measurement is completed by four pixels; the sub-wavelength unit structure forms a super-pixel unit, and the super-pixel unit is aligned and integrated with a focal plane detection array in a two-dimensional array form to form a compact polarization camera facing focal plane segmentation. The device is simple in structure, easy to integrate with the CMOS front end, small in device size, low in power consumption and high in mass production feasibility.

The invention relates to a micro display device for a bifocal plane HUD (head up display) system, which solves the problems of halved field of view, limited working bandwidth, low color saturation and low brightness of the existing bifocal plane HUD system, and comprises an image display module and a polarization modulation element arranged above the image display module, the polarization modulation element is used for polarization modulation of display pixels, the effective area of the sub-wavelength medium grating arrangement is equivalent to a 1 / 2 wave plate, the display pixels are separated in a row-by-row or column-by-column staggered mode through the sub-wavelength medium grating arrangement, and the problem that the view field is halved due to an existing target surface space partitioning scheme is solved. The two adjacent sub-wavelength medium gratings convert incident light into linear polarization states in two directions, the two directions are mutually orthogonal, and the two spaced sub-wavelength medium gratings are completely the same, so that the two images are respectively adjusted into the mutually orthogonal linear polarization states, and the two images are generated in a staggered manner.

The invention relates to the technical field of optical metasurface and light field regulation and control, in particular to a light pressure multi-dimensional regulation and control method and device based on a metasurface microstructure array. The method comprises the following steps: designing and preparing a metasurface microstructure array, wherein the microstructure array is composed of a plurality of sub-wavelength scale three-dimensional microstructure units arranged on a dielectric substrate; surface plasmon resonance is excited by adjusting structural parameters of the three-dimensional microstructure units and adjusting working parameters of a light source acting on the microstructure array, and near-field localization and enhancement are achieved. And calculating, regulating and controlling the light pressure borne by the metasurface microstructure array based on the Maxwell stress tensor. The method can keep a remarkable light pressure enhancing effect in a wide spectrum range of 380-1300 nm, and is suitable for various material systems such as silver, gold and the like. The method can be applied to the fields of optical tweezers systems, optical control devices, precision measurement and the like, and has the advantages of flexible design, simplicity and convenience in preparation, high regulation and control precision and the like.

The invention discloses a polarization insensitive filter based on a sub-wavelength grating structure, and belongs to the technical field of integrated photonic devices. The filter comprises an input transition waveguide, a multimode waveguide grating and an output transition waveguide which are connected in sequence. The multimode waveguide grating is composed of a central sub-wavelength grating waveguide and Bragg gratings symmetrically distributed on the two sides, and the effective refractive indexes of TE polarization and TM polarization are equal by adjusting the waveguide width and duty ratio of the central sub-wavelength grating, so that the polarization sensitivity of the device is eliminated fundamentally. And the input / output transition waveguide adopts a transition mode of mixing a tapered waveguide and a sub-wavelength grating waveguide, so that low-loss mode transmission between a straight waveguide and a multimode grating is realized. According to the invention, the anisotropic equivalent medium characteristic of the sub-wavelength grating is utilized, a function of simultaneously and effectively filtering TE and TM polarization is realized, and the filter has the advantages of polarization insensitivity, flexible design, compact structure, simple process and compatibility with a CMOS (Complementary Metal Oxide Semiconductor) process, and has important application value in the fields of optical communication, optical interconnection and the like.

The invention discloses a logic chip mask defect detection method, and relates to the technical field of integrated circuit manufacturing, and the method comprises the following steps: S1, constructing a scattering response model of sub-wavelength inorganic particles on the surface of a mask, and constructing a scattering response model of sub-wavelength inorganic particles on the surface of the mask under a set multi-angle polarized light incidence condition; non-linear disturbance influence of inorganic particles with different particle sizes on the reflected light phase in each incident polarization state is simulated, and a scattering response template containing standard phase disturbance characteristics is generated; and S2, based on a scattering response template, carrying out pixel-by-pixel matching analysis on the acquired multi-angle polarization phase diagram on the surface of the mask, identifying a local area matched with the template, and marking the local area as a suspected scattering interference area. According to the method, through construction of the scattering response template and multi-angle polarization consistency analysis, accurate distinguishing of artifacts and real defects is achieved, the recognition precision and stability under complex interference are improved in combination with structure retention type phase reconstruction and dynamic threshold recognition, and mask quality control and photoetching yield improvement are facilitated.

The invention discloses a trace biochemical sensor based on deep sub-wavelength singular point resonance, the sensor comprises an upper metal layer, a middle dielectric layer and a lower metal layer which are stacked in sequence from top to bottom, the upper metal layer is a deep sub-wavelength singular point resonance structure pattern, the lower metal layer is an excitation microstrip line, and the middle dielectric layer is a deep sub-wavelength singular point resonance structure pattern. Resonance of the deep sub-wavelength singular point resonance structure pattern is excited by the excitation microstrip line. By effectively adjusting the rotation angle of the deep sub-wavelength singular point resonance structure graph, the resonance mode field of the sensor is gradually evolved into a singular point resonance mode from a hybrid bonding and anti-bonding intrinsic resonance mode. According to the sensor, the equivalent working wavelength of the deep sub-wavelength artificial local surface plasmon resonance unit is compressed, and the electromagnetic field enhancement characteristic of a singular point resonance mode and the square root dependency relationship of tiny dielectric disturbance are combined, so that the high-sensitivity resolution of trace biochemical quantity is realized in a low-frequency microwave band.

Various embodiments may relate to an electro-optic modulator. The electro-optic modulator may include a waveguide configured to carry optical light along a longitudinal length of the waveguide. The electro-optic modulator may also include a first electrically conductive sub-wavelength grating on a first side of the waveguide, the first electrically conductive sub-wavelength grating including a plurality of fingers extending substantially perpendicular to the longitudinal length of the waveguide. The electro-optic modulator may further include a second electrically conductive sub-wavelength grating on a second side of the waveguide opposite the first side, the second electrically conductive sub-wavelength grating including a plurality of fingers extending substantially perpendicular to the longitudinal length of the waveguide. The electro-optic modulator may be configured to modulate the optical light upon application of a potential difference between the first electrically conductive sub-wavelength grating and the second electrically conductive sub-wavelength grating based on Pockels effect.

The invention belongs to the technical field of visible light detection, and aims to realize accurate detection of multicolor visible light and monolithic integration of a multi-wavelength receiver. The invention provides a fully-integrated multicolor visible light detector based on a sub-wavelength polycrystalline silicon grating, which comprises three detectors capable of selectively detecting blue, green and red signals respectively. The principle is as follows: a one-dimensional sub-wavelength polycrystalline silicon grating in the multicolor detector is embedded in an upper SiO2 layer and a lower shallow trench isolation region to form a dielectric waveguide structure of which the middle is a high-refractive-index medium and the periphery is a low-refractive-index oxide layer. The period and the grating width of the sub-wavelength grating are changed, so that the incident polarized light and the sub-wavelength periodic structure are strongly coupled to cause a guided-mode resonance effect, and the sub-wavelength grating can be applied to a transmission optical filter. The size and the cost of the multicolor visible light communication system can be effectively reduced, and the data transmission rate of the system is greatly improved.

The invention discloses a PINN-based infrared window surface anti-reflection micro-nano structure optimization design method, which is oriented to a sub-wavelength microstructure (such as a square column array or a cylinder array) on the surface of an infrared optical window, and comprises the following steps of: integrating physical constraints into a neural network model; and high-precision prediction of the reflectivity of the micro-nano structure and intelligent optimization of structural parameters are realized. Aiming at the characteristics of data scarcity and high dimension of design parameters, the invention provides innovative designs such as a parameter space sampling strategy, a PINN model architecture, a physical constraint fusion strategy and a training optimization method, and can effectively solve the problems of long time consumption, large data demand, poor model generalization performance and the like of a traditional design method. And infrared anti-reflection micro-nano structure parameters which meet physical rules and are excellent in performance can be obtained under the condition of less simulation data. According to the technical scheme, intelligentization and high efficiency of infrared window anti-reflection micro-nano structure parameter design are achieved.

The invention relates to the technical field of electromagnetic functional materials, in particular to a nested hexagonal resonant structure wave-absorbing metamaterial and a preparation method and application thereof. The wave-absorbing metamaterial with the nested hexagonal resonant structure sequentially comprises a metal resonant layer, a homogeneous wave-absorbing coating and a metal matrix layer, the metal resonance layer is formed by periodically arranging a plurality of metal resonance units on the surface of the homogeneous wave-absorbing coating in an array manner; each metal resonance unit is of a nested hexagonal structure formed by arranging a plurality of structural units, and each structural unit is a hollow hexagonal metal patch. Through the combination of the homogeneous wave-absorbing coating and the metal resonance layer, the wave-absorbing metamaterial with the nested hexagonal resonance structure not only can realize effective absorption of an S wave band under the sub-wavelength scale, but also is beneficial to widening the effective absorption bandwidth and improving the absorption efficiency, simplifies the complex layered stacking framework of a traditional broadband wave absorber from the structural design, and has the advantages of simple structure and low cost. The method has the engineering application advantages of high process adaptability, high preparation feasibility and the like.

The invention discloses a multi-wavelength high-polarization-degree straight-cavity surface emitting laser which is structurally composed of a plurality of connecting layers and comprises a lower electrode layer, a substrate layer, a lower DBR layer, a lower spacing layer, a lower waveguide layer, a quantum well layer, an upper waveguide layer, an upper spacing layer, an upper DBR layer and an upper electrode layer. The upper waveguide layer comprises a plurality of strip-shaped waveguides which are arranged in parallel in the same plane and have different widths, and filling materials filled among the plurality of strip-shaped waveguides. And the width change of the plurality of strip-shaped waveguides is an arithmetic progression of periodic circulation. Through the design of the upper waveguide layer structure, the growth speed difference can be realized, the thickness difference of the spacing layer is accurately controlled, and the laser wavelength is adjusted. Compared with a traditional method, high cost and technical problems caused by using a sub-wavelength grating are avoided.

The invention provides a heterogeneous integrated sub-wavelength structure end face coupler adaptive to a single-mode optical fiber and a preparation method of the heterogeneous integrated sub-wavelength structure end face coupler, and relates to the technical field of integrated optics. The coupler comprises a substrate, an insulating layer, a waveguide layer and a cladding from bottom to top. The waveguide layer comprises an upper lithium niobate ridge waveguide and a lower lithium niobate ridge waveguide, the lower waveguide is wider than the upper waveguide, and the upper waveguide is used for connecting an external waveguide; the heterogeneous integrated coupling region comprises a silicon nitride strip conical waveguide which forms directional coupling with the lower-layer lithium niobate waveguide, so that adiabatic transfer of a light field is realized; the sub-wavelength grating regulation and control region sequentially comprises a silicon nitride tapered waveguide and sub-wavelength grating combination section, a width gradually-changing grating section and an equal-width buffer grating section. The whole structure is symmetrical about the central axis. Through the multi-section adiabatic transformation and heterogeneous integration design, efficient expansion of a mode field is achieved, the coupling efficiency with a single-mode fiber is improved, and the advantages of being insensitive to polarization, good in process compatibility and suitable for high-density integration are achieved.

The invention provides a sub-wavelength structure unit and a preparation method thereof, a reflective array and a broadband planar film antenna, and the sub-wavelength structure unit comprises a sub-wavelength structure, a metal reflective layer, a first film and a second film. The sub-wavelength structure comprises at least two types of single resonant structures; the at least two types of single resonance structures are arranged on the first thin film; the metal reflecting layer is arranged on the second thin film; a spacing layer is arranged between the first film and the second film; and the phase and dispersion characteristics of the sub-wavelength structure unit in the first resonance area and / or the second resonance area are determined by setting parameters of the single resonance structure. According to the invention, the sub-wavelength structure comprises multiple types of single-resonant structures for forming different multi-resonant sub-wavelength structures, so that the problem of narrow bandwidth of a single-layer film antenna formed by the sub-wavelength structure unit can be solved.

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 discloses a metasurface based on a nano resonator and a design method for realizing wavelength classification deflection. The metasurface is formed by periodically arranging three unit silicon nano resonators, wherein the widths of middle layers of the unit silicon nano resonators change in a gradient mode along the x axis, and the metasurface is of the sub-wavelength scale. The substrate of the unit resonator is a silver substrate, the surface of the silver substrate is provided with a silicon nanometer strip, and the top of the silicon nanometer strip and the top of the silver substrate are respectively deposited and covered with a layer of silver film; by adjusting the thickness of the middle silicon layer of the resonator, the working wavelength of a near-infrared band can be regulated and controlled, normal incident y polarized light with a specific wavelength is deflected to a diffraction order, light with other wavelengths is vertically reflected, and meanwhile, a phase modulation function is achieved. The device has the remarkable advantages of simple structure and convenience in preparation, has the advantages of high throughput and large-area preparation, and has important application prospects in new technologies such as optical imaging, spectrum detection and machine vision.

The invention provides an image sensor pixel unit with a polarization response characteristic light trapping structure and a preparation method of the image sensor pixel unit. The image sensor pixel unit comprises a semiconductor substrate, a multi-layer structure arranged on the substrate and a polarization response unit. The multi-layer structure comprises an anti-reflection layer, a filling and leveling layer and a micro-lens layer. The polarization response unit adopts an all-dielectric sub-wavelength grating based on a backscattering technology, and the polarization response unit and the deep trench isolation structure are synchronously formed by adopting the same process, so that photoelectric isolation between pixels is realized, and a polarization selection function is also realized. The anti-reflection layer is a multi-layer dielectric film stack, and interface reflection is effectively restrained. By optimizing the design of a polarization selection-transmission-convergence cooperative structure, polarization selection and light enhancement functions are integrated, an all-dielectric material system is adopted to be completely compatible with a CMOS (complementary metal oxide semiconductor) process, and quantum efficiency is remarkably improved while high-efficiency polarization detection is realized.

The invention discloses a near-earth space all-day star sensing system based on a sub-wavelength metal grating and a working method thereof, and belongs to the technical field of star sensors. In order to increase the number of fixed stars which can be detected by the near-earth space all-time star-sensitive system, the near-earth space all-time star-sensitive system comprises an optical system, an InGaAs detector, a spectrum optical filter, a micro-polaroid array, a memory, a processor, a control unit and a time unit, the InGaAs detector is respectively connected with the micro-polaroid array, the memory and the control unit; the micro-polaroid array is connected with the optical system, and the optical system is connected with the spectrum optical filter; the memory is respectively connected with the processor and the time unit; and the processor is connected with the control unit. According to the invention, the polarization filtering work of the sky background is realized, and the number of observable fixed stars is effectively increased on the basis of ensuring the miniaturization of a near-earth space all-day star-sensitive system.

The invention relates to a quaii-BIC chiral metasurface device based on refractive index modulation and a preparation method and application thereof.The chiral metasurface device comprises a plurality of sub-wavelength structure partitions which are sequentially arranged along the X axis, and every two adjacent sub-wavelength structure partitions are rotationally and symmetrically arranged relative to the Y axis; a sub-wavelength structure in the sub-wavelength structure partition comprises at least two optical dielectric layers which are stacked along the Z axis, at least one sub-wavelength structure in the sub-wavelength structure partition is obliquely arranged relative to the Y axis, and a refractive index difference exists between the at least two optical dielectric layers, so that the metasurface device realizes intrinsic chirality. The metasurface device realizes tunable strong intrinsic chirality at multiple wavelengths, and the preparation method has the advantages that the processing difficulty is low, the thickness of the optical dielectric layer is low, the thickness and the inclination angle of the optical dielectric layer do not need to be accurately controlled, the lift-off process is compatible, and high-precision large-area metasurface device preparation can be realized.

The invention discloses a polarization independent mode multiplexing / demultiplexing device based on a transverse sub-wavelength grating structure, and belongs to the technical field of photoelectrons. The device adopts an asymmetric directional coupler structure and mainly comprises a bus waveguide formed by a transverse sub-wavelength grating waveguide and a coupling waveguide parallel to the bus waveguide. The core is that longitudinal sub-wavelength grating waveguides with specific duty ratios are introduced to the coupling side of a bus waveguide and the two sides of a coupling waveguide, and accurate matching of dual-polarization-state effective refractive indexes and coupling lengths is achieved through combined regulation and control of geometric parameters of transverse and longitudinal gratings. And the dual-polarization fundamental mode in the coupling waveguide and the dual-polarization same-order high-order mode in the bus waveguide can realize synchronous conversion in a coupling region. The invention overcomes the defect of strong polarization correlation of the traditional device, has the advantages of polarization independence, low crosstalk, low insertion loss, compact structure, high process tolerance, easiness in mode expansion and the like, and can be used for multi-dimensional multiplexing transmission in optical communication and optical interconnection systems.

The invention provides a high-purity structural color device based on a metasurface and a color developing method, and relates to the technical field of structural color metasurface, the structural color device is a double-layer nanoring array based on an all-dielectric metasurface, adopts an optical design based on Fabry-Perot interference and Mie resonance, and comprises a plurality of structural units, the structure unit comprises a vertical stacking double-layer circular ring structure formed by a tantalum pentoxide Ta2O5 functional layer and a silicon dioxide SiO2 top cover layer, and has sub-wavelength periodic two-dimensional arrangement; through the technical path of the invention, a structural color solution with high purity, wide color gamut and high reflection is provided by utilizing the wide band gap characteristic and high-quality manufacturing capability of Ta2O5. The application scenarios include but are not limited to high-end displays, optical sensors, information encryption and precision optical elements, and brand new possibility is provided for development of the next generation of photonics technology.

The invention discloses a far-infrared silicon-based high-transmittance metasurface and a designing and processing method, and relates to the field of micro-nano optical devices. The metasurface is of a layered stacking structure with a hole-type metasurface atom array layer as a center layer, and an upper antireflection film layer, an upper substrate layer, the hole-type metasurface atom array layer, a lower substrate layer and a lower antireflection film layer are sequentially arranged on the metasurface from the incident side to the emergent side. Each of the upper antireflection film layer and the lower antireflection film layer comprises a first antireflection layer and a second antireflection layer which are sequentially arranged from inside to outside; the hole-type super-structure atom array layer, the upper substrate layer and the lower substrate layer are all made of monocrystalline silicon. According to the invention, the equivalent refractive index of the matching interface is designed through the sub-wavelength structure, the reflectivity of the far infrared band of 8-12 [mu] m is improved to 95% or more under the condition of no loss, the process route is simple, and the microstructure units of the surface of the super-structure are packaged and protected by using the silicon-silicon bonding process, so that the stability of the surface of the super-structure in processing and application is improved.