246 results about "Sub wavelength" patented technology

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.

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 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 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 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 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 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 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 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 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 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.

An infrared detector includes a tuning fork resonator comprising an mechanical-to-electrical transduction mechanism; a metamaterial absorber residing on at least one side of the tuning fork resonator, the metamaterial absorber comprising at least a material layer with subwavelength inclusions; and a signal processing circuit to translate the electrical signal into an amplitude of mechanical motion of the tuning fork.

The invention relates to the technical field of optical interference measurement, in particular to a synchronous wavelength phase-shifting interference measurement system. According to the scheme, a laser set outputs multiple narrow-linewidth light beams with nm-level wavelength spacing, and the multiple narrow-linewidth light beams are combined through a wavelength division multiplexer and then enter an interference light path to generate multi-wavelength interference fringes. The metasurface achieves separation of interference fringes of all wavelengths through a sub-wavelength structure array, a detector synchronously captures light intensity data of the interference fringes of all the wavelengths in a single frame mode, and then phase distribution can be directly calculated through single-frame multi-wavelength light intensity. According to the system, mechanical phase shifting and polarization control assemblies are eliminated, the defects that a traditional wavelength phase shifting interference measurement technology is poor in environmental adaptability and a traditional synchronous phase shifting technology has polarization errors are overcome, and a high-precision and high-environmental-adaptability dynamic measurement scheme is provided for optical manufacturing.

The invention relates to a reflective AR diffractive optical waveguide lens, which comprises a waveguide substrate, an input diffractive optical element, an output diffractive optical element, a low refractive index filling layer, a sub-wavelength diffractive microstructure and / or a diffractive optical film, and is characterized in that the input diffractive optical element couples a light beam into the waveguide substrate; coupled light beams are totally reflected in the waveguide substrate and then are coupled out by the output diffractive optical element step by step, the low-refractive filling layer is embedded in a grating gap between the input diffractive optical element and the output diffractive optical element, and the height of the low-refractive filling layer exceeds that of the input diffractive optical element and the output diffractive optical element. And the sub-wavelength diffraction microstructure and / or the diffraction optical film are / is arranged on the low-refractive-index filling layer and are / is arranged opposite to the output diffraction optical element. According to the invention, an air capping plate layer for protecting a grating in an AR lens is replaced, the size of the lens is reduced, and the sub-wavelength diffraction microstructure and / or the diffraction optical film on the low-refraction filling layer can solve the problems of rainbow lines, light leakage, transmittance and the like caused by diffraction optical waveguides on the basis of not influencing the optical performance.

The invention relates to a variable-focus metamaterial lens system. The system comprises a first metasurface and a second metasurface. A first metasurface and a second metasurface are sequentially arranged on the same optical axis, and a preset distance is reserved between the first metasurface and the second metasurface. A group of sub-wavelength structure units are constructed on the surface of the first metasurface; a group of sub-wavelength structure units are constructed on the second metasurface, and the second metasurface rotates by an angle theta around the normal direction relative to the first metasurface; the equivalent phase distribution of the composite device can be adjusted through the relative rotation between the first metasurface and the second metasurface, and the continuous regulation and control of the focal length are realized along with the change of the numerical aperture. Therefore, the complexity is reduced, and the response speed is improved.

The invention discloses a terahertz polarization-independent achromatic beam deflection device and a use method thereof, and belongs to the technical field of terahertz application. The terahertz polarization-independent achromatic beam deflection 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 dielectric cylinder superatoms arranged in an array mode, the dielectric cylinder superatoms are of a sub-wavelength structure, and the distances between the dielectric cylinder superatoms in the adjacent rows and between the dielectric cylinder superatoms in the adjacent columns are all smaller than the wavelength of incident terahertz waves; the dielectric cylinder superatoms and the corresponding substrate form a basic unit of the light beam deflection device. According to the polarization-independent achromatic light beam deflection device, the achromatic effect of any polarization can be achieved within the broadband range of 0.6 THz-1. 2 THz.

The embodiment of the present application provides a grating encoder and an encoding method, and relates to the technical field of integrated optical devices. The grating encoder comprises an optical signal input end, a mode regulation area and an optical signal output end, the mode regulation area comprises a substrate, at least two straight waveguides and at least one subwavelength grating waveguide; the at least two straight waveguides and the at least one subwavelength grating waveguide are alternately and equally spaced arranged on the substrate; the duty cycle of one subwavelength grating waveguide in the unit where the subwavelength grating waveguide is located is 0.5, and the unit is composed of the subwavelength grating waveguide, the straight waveguide alternately arranged with the subwavelength grating waveguide and the interval between the subwavelength grating waveguide and the straight waveguide; one subwavelength grating waveguide and one straight waveguide alternately arranged with the subwavelength grating waveguide jointly constitute one unit cell, and each individual unit cell contains one normalized flux. The signal strength attenuation and mode distortion are reduced.

The application discloses a hybrid plasmonic optical waveguide, which comprises an oxidation protection layer and an alkali metal layer, wherein the oxidation protection layer and the alkali metal layer do not react under normal temperature conditions, and the alkali metal layer is sodium or potassium. The application can further improve the mode field confinement capability of the hybrid plasmonic waveguide, realize low-loss plasmonic mode transmission, and has important application value in the field of subwavelength photonic integration in a communication waveband.

A hyperbolic metamaterial is provided. The hyperbolic metamaterial includes a substrate and sub-wavelength nanostructures arrayed on the substrate. Each sub-wavelength nanostructure has a decreasing cross-sectional area with increasing height from the substrate and includes dielectric or semi-metallic material layers and metal-insulator transition (MIT) material layers respectively interleaved with the dielectric or semi-metallic material layers. Each MIT material layer and each dielectric or semi-metallic material layer of each sub- wavelength nanostructure has a cross-sectional shape characterized in that current is induced in one or both of the dielectric or semi-metallic material layers and the MIT material layers by exposure to a magnetic field.

This invention discloses a visible transparent, ultra-wideband microwave absorption structure, comprising, from top to bottom, a visible transparent spatial shielding layer, an impedance-gradient absorption layer, and a total reflection bottom layer. The spatial shielding layer is highly transparent to the microwave band. The impedance-gradient absorption layer is composed of multiple layers of low-dielectric-constant transparent dielectric substrates and an array of transparent conductive patterns disposed thereon, stacked alternately. The total reflection bottom layer is totally reflective to the microwave band. By precisely designing the gradient period and equivalent resistance of the multilayer transparent conductive pattern array, and utilizing the electromagnetic coupling and multi-point resonance mechanism of the upper and lower layers, this invention achieves ultra-wideband microwave strong absorption of more than 90% in the 1-40 GHz frequency band at the subwavelength scale, breaking through the bandwidth limitation bottleneck of traditional microwave absorbing structures; and it also possesses excellent visible light transparency characteristics.

According to one embodiment, a display structure comprises: a waveguide (101); a coupling-in structure (102) on a first side (110) of the waveguide (101), comprising a diffraction grating feature and a sub-wavelength grating feature, and configured to receive light (104) comprising a first polarization and a second polarization, where the diffraction grating feature is configured to couple at least a portion of the first polarization to the waveguide as coupled-in light (105), and where the sub-wavelength grating feature is configured to couple at least a portion of the second polarization to the waveguide as coupled-in light (105). The sub-wavelength grating feature is configured such that the diffraction grating feature is at least partially transparent to the second polarization; and a polarization steering grating (103) on the second side (111) of the waveguide (101) configured to receive at least a portion of the coupled light (105) and to rotate the polarization of the coupled light (105), generating polarization-rotated coupled light (106) when the coupled light (105) is reflected back from the second side (111) of the waveguide (101) back to the first side (110) of the waveguide (101).

The application relates to a two-stage refractive index gradient mode spot converter based on a metamaterial and a preparation method thereof, and belongs to the technical field of silicon light, wherein the converter comprises a silicon substrate, a buried oxygen layer located on the silicon substrate, a subwavelength grating waveguide structure and a solid waveguide structure located on the buried oxygen layer, and a gradient refractive index upper cladding layer located on the subwavelength grating waveguide structure and the solid waveguide structure; the subwavelength grating waveguide structure and the upper cladding layer can transversely and longitudinally amplify a mode field, can effectively reduce substrate absorption loss, and can increase alignment tolerance; by designing a subwavelength grating duty cycle and an upper cladding layer two-material duty cycle, the refractive index is gradually changed along the light propagation direction, the distribution of light field energy is better controlled, the light field is gradually expanded and adapted in space, the mode mismatch problem can be effectively avoided, and the design freedom is enhanced.

The invention discloses a passive phase shifter which comprises a first waveguide arm and a second waveguide arm, the first waveguide arm comprises a first sub-wavelength grating, the duty ratio of the first sub-wavelength grating is a first duty ratio, the second waveguide arm and the first waveguide arm are oppositely arranged, the second waveguide arm comprises a second sub-wavelength grating, the duty ratio of the second sub-wavelength grating is a second duty ratio, and the duty ratio of the second sub-wavelength grating is a second duty ratio. The duty ratio of the first sub-wavelength grating is a first duty ratio, the duty ratio of the second sub-wavelength grating is a second duty ratio, the first duty ratio is different from the second duty ratio, and the light waves are combined to form a phase difference after passing through the first waveguide arm and the second waveguide arm respectively. The insensitivity of the sub-wavelength grating structure to the wavelength is utilized, so that the working bandwidth of the passive phase shifter is increased, stable phase shifting of large-bandwidth light waves is achieved, the passive phase shifter can meet the use requirements of more light wave bandwidths, and the application range of the passive phase shifter is expanded.

The invention discloses a micro-nano structure for realizing window efficient transmission under the condition of maximum-angle incidence and a design method. The design method comprises the following steps: selecting an optical material with good optical transmission performance as a material of a bionic moth eye micro-nano structure window; deriving structural design parameters; selecting a proper bionic moth eye micro-nano structure type; the preliminarily designed bionic moth eye micro-nano structure is optimized through simulation software, so that the optimal high transmittance is achieved; and optimizing and modifying the bionic moth eye micro-nano structure, and verifying the bionic moth eye micro-nano structure by using simulation software to determine the maximum-angle incidence bionic moth eye micro-nano structure. According to the method, a high-transmittance bionic moth eye micro-nano structure window is designed by combining simulation software on the basis of a preliminarily designed bionic moth eye micro-nano structure according to optical theories such as a sub-wavelength diffraction theory and an equivalent medium theory. Compared with a common bionic moth eye micro-nano structure window, the window can meet the observation and detection requirements of a visual angle close to 180 degrees under the condition of large-angle incidence.

The application provides a high-resolution color holographic structure preparation method, and specifically comprises the following steps: S1, obtaining three-dimensional information of an object; S2, extracting and separating three primary color channels of an image array; S3, setting a convolution kernel, and respectively performing convolution on each color channel component of each image; S4, respectively performing pooling on the extracted data; S5, respectively extracting the numerical values of each same coordinate position in the set to form a new data set by using an addressing method; S6, designing three surface relief gratings with different periods according to a grating equation; S7, respectively performing point multiplication on the three primary color matrices and the grating data; S8, re-fusing the encoded three color channel data; and S9, manufacturing the data file into a moldable subwavelength level surface relief structure by a micro-nano processing method. The application converts surface relief micro-nano structures by separating, optimizing, fusing and encoding the multi-angle sampling image array data, and the imaging space has strong stereoscopic sense, bright color, strong detail performance and great imitation difficulty.

The application provides a broadband wave plate and a polarization grating based on a sub-wavelength structure, and relates to the technical field of optical elements. The broadband wave plate comprises a substrate, an antireflection layer on one side of the substrate, and a periodically arranged columnar sub-wavelength structure on the other side of the substrate, wherein the columnar sub-wavelength structure comprises a plurality of sub-wavelength structure layers of different refractive index media. The broadband wave plate and the polarization grating provided by the application can effectively reduce the reflection of light, improve the transmittance and polarization conversion efficiency, because the columnar sub-wavelength structure comprises a plurality of sub-wavelength structure layers of different refractive index media, and the refractive index of the columnar sub-wavelength structure can be matched with the impedance of air.

The invention discloses a full-polarization light-splitting type super-structure surface covering a mid-infrared broadband and a method of the full-polarization light-splitting type super-structure surface. The super-structure surface is formed by periodically arranging super-structure units, each super-structure unit comprises three groups of nano-structures used for regulating and controlling different cross-polarization, each group of nano-structures respectively control a pair of cross-polarization, each group of nano-structures comprises three anisotropic nano-columns, and the nano-columns of the three groups of nano-structures are arranged in a staggered manner. According to the invention, on the basis of the structural design of space polarization multiplexing, the independent regulation and control capability of the metasurface on the phase, amplitude and polarization state of a light field is fully utilized, the metasurface with polarization selective response is constructed, and the full Stokes polarization decomposition and focusing function of the mid-infrared broadband (3-5 [mu] m) is realized at the sub-wavelength scale; incident light in different polarization states can be respectively focused to different spatial positions, so that the polarization beam splitting efficiency and the imaging quality are remarkably improved, and the application of polarization information in complex light field detection and infrared imaging is promoted.

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