485 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 invention discloses a deep sub-wavelength scatterer particle size evaluation method based on coherent axial diffraction calculation, and belongs to the technical field of optical imaging and microstructure analysis, and the deep sub-wavelength scatterer particle size evaluation method comprises the following steps: obtaining an image, and preprocessing the image; quantifying the preprocessed image, obtaining the scattered light energy concentration of each axial position of an image surface scatterer, obtaining the attenuation condition after scattered light energy defocusing based on the scattered light energy concentration, and compensating defocusing attenuation; the method comprises the following steps: extracting a peak value position and a width of a main peak, carrying out correlation analysis on the extracted peak value position and width data of the main peak and the corresponding scatterer feature size based on a deep sub-wavelength scatterer sample with a known feature size, and constructing a peak value position mapping function and a peak width mapping function; and performing particle size evaluation based on the constructed function. According to the method, the problems of low signal-to-noise ratio, large out-of-focus interference, poor applicability and the like of a traditional method are solved, and the precision and the universality of particle size evaluation are remarkably improved.

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 data processing method and device, a computer program product, equipment and a medium, and the method comprises the steps: obtaining to-be-processed data, and inputting the to-be-processed data into a data processing model, the data processing model comprises an interference gating module constructed based on an interferometer, an interference fine tuning module, and a plurality of diffraction expert modules constructed based on sub-wavelength units; determining one or more data flow direction objects matched with the to-be-processed data according to an interference gating module in the data processing model; according to a diffraction expert module matched with the data flow direction object in the data processing model, performing data processing on the to-be-processed data to generate a first processing result; and processing the first processing result according to an interference fine tuning module in the data processing model to output a target processing result. On the basis of an interference-diffraction model architecture, all data processing steps are completed on an optical calculation device, and performance loss caused by frequent photoelectric conversion / digital-to-analog conversion is avoided, so that the overall data processing speed is increased.

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.

A device including a stack of silicon meta-optical layers forming a meta-material comprising an input surface for receiving terahertz electromagnetic radiation, an output surface for outputting a plurality of beams of the electromagnetic radiation; and a spatially varying permittivity varying with sub-wavelength precision across a volume of the stack, wherein the spatially varying permittivity is configured to focus different spectral bands of the electromagnetic radiation into different spatially separated electromagnetic modes.

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.

An optical element, as well as a metasurface formed by such optical elements, for use in photonic devices, are presented. The optical element is configured and operable as a sub-wavelength resonator having predetermined optical properties defining an optical response to incident light, wherein the optical element is configured as a metal-free multi-material structure of predetermined geometry and dimensions in which each two interfacing materials have positive and negative thermo-optic coefficients, respectively, such that the optical element has a near-zero effective thermo-optic coefficient, thereby providing substantial temperature invariance of said optical properties in predetermined wavelength and temperature ranges.

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.

An acoustic lens to steer an acoustic beam includes a first structure, a second structure spaced from the first structure, an array of projections disposed between the first and second structures, each projection of the array of projections extending from the first structure toward the second structure to define a respective gap between the projection and the second structure, and an actuator configured to move the first structure, the second structure, or the array of projections for collective adjustment of the respective gaps of the array of projections. Each projection is configured to define one or more respective unit cells, each unit cell having a sub-wavelength size relative to the acoustic beam to establish an effective refractive index profile for the acoustic beam between the first and second structures. The actuator is configured such that the collective adjustment of the respective gaps varies across the array of projections to spatially modify the effective refractive index profile to steer the acoustic beam.

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 utility model provides an anti-reflection film and a super lens, and the anti-reflection film comprises anti-reflection structures which are arranged in an array, and the anti-reflection structures are sub-wavelength structures; the filling structure is arranged between the anti-reflection structures; the antireflection film is used for the super lens, and the super lens comprises a substrate and micro-nano structures which are arranged on the substrate in an array mode. The antireflection film is arranged on a target interface; the media on the two sides of the target interface at least comprise the micro-nano structure or the substrate. According to the antireflection film provided by the invention, the light transmittance of the super lens is more ideal.

The on-chip refractive index sensor comprises a silicon-based substrate, a buried oxide layer, a silicon waveguide layer and an upper cladding layer, the buried oxide layer grows on a first surface of the silicon-based substrate, the silicon waveguide layer grows on one surface, far away from the silicon-based substrate, of the buried oxide layer, and the upper cladding layer grows on the other surface of the buried oxide layer. And the upper cladding covers one surface, far away from the silicon-based substrate, of the buried oxide layer and wraps the silicon waveguide layer. The silicon waveguide layer is formed by connecting and coupling a micro-ring group, an upper straight waveguide and a lower straight waveguide in series, the straight waveguides and the micro-ring group are of sub-wavelength grating groove type structures, the micro-ring group comprises two or more SWGS micro-rings, and the left end and the right end of the upper SWGS straight waveguide are sequentially connected with input strip-shaped waveguides, namely sub-wavelength grating groove waveguide transition waveguide structures, which are in mirror symmetry. Compared with a traditional refractive index sensor based on a single nanowire waveguide resonant ring structure, the scheme has the advantages of higher detection sensitivity, larger measurable refractive index range and the like.

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 discloses a photoelectric detector and a preparation method thereof. The photoelectric detector comprises a P-type junction region, an N-type junction region and an intrinsic absorption layer, wherein the P-type junction region and the N-type junction region are arranged on a substrate; the intrinsic absorption layer is arranged between the P-type junction region and the N-type junction region; and the optical metasurface structure is arranged on the intrinsic absorption layer of the light incident plane, and the optical metasurface structure is formed by an array of basic units formed by periodically arranging different sub-wavelength structures. According to the photoelectric detector, the local light field intensity on the intrinsic absorption layer can be effectively enhanced, so that the quantum efficiency of the photoelectric detector can be effectively improved, meanwhile, the thickness of the intrinsic absorption layer can be reduced, the response speed is further enhanced, and the absorption range of a communication waveband spectrum can be enhanced.

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.