An ultra-wideband large-angle beam splitter based on a similar metasurface structure

Abstract

The present invention discloses an ultra-wideband large-angle beam splitter based on a similar supersurface structure, each of which is fixedly connected to the substrate and located on the top of the substrate, and a plurality of the similar supersurface structures are periodically distributed along the X direction and the Y direction. The ultra-wideband large-angle beam splitter based on the similar supersurface structure always maintains the same transmission intensity of the 1st order and the +1st order in the working band. In the range of 678 to 833nm, the transmittance of the ±1 diffraction order can be maintained above 35%, the total transmittance is greater than 74%, the +1st order transmittance is greater than 35%, and the deflection angle can reach 48.88° to 67.75°. In most wavelengths in the working band, the phase of the transmitted light of the ultra-wideband large-angle beam splitter based on the similar supersurface structure can maintain a phase difference of π, thereby realizing ultra-wideband equal power beam splitting.

Description

Technical Field

[0001] The present invention relates to the technical field of optical beam splitters, and in particular to an ultra-wideband large-angle beam splitter based on a similar metasurface structure. Background Art

[0002] In the current research and application of modern optics, metasurfaces are attracting more and more attention from researchers due to their ultra-thin structure and ability to precisely control electromagnetic fields. Metasurfaces are a special type of ultra-thin artificial electromagnetic metamaterial that can flexibly and effectively control the phase, polarization mode, propagation mode and other characteristics of electromagnetic waves at a subwavelength scale, thereby achieving functions such as focused imaging, anomalous deflection, perfect absorption and polarization rotation. Compared with traditional "bulk metamaterials", metasurfaces have significant advantages such as small size, thin thickness, easy preparation and integration. At the same time, they are also more flexible and precise in controlling light. However, discrete antenna array structures have the problem of narrow working bandwidth. Summary of the invention

[0003] The purpose of the present invention is to provide an ultra-wideband large-angle beam splitter based on a similar metasurface structure, aiming to solve the technical problem of narrow working bandwidth of discrete metasurface structures in the prior art.

[0004] To achieve the above-mentioned purpose, the present invention adopts an ultra-wideband large-angle beam splitter based on a similar supersurface structure, including a substrate and a plurality of similar supersurface structures, each of the similar supersurface structures is fixedly connected to the substrate and is located on the top of the substrate, and the plurality of similar supersurface structures are periodically distributed along the X direction and the Y direction.

[0005] Wherein, the material of each of the similar super-surface structures is Si, and the height is 190nm;

[0006] The material of the substrate is SiO 2 , height is 1000nm.

[0007] Each of the similar supersurface structures includes two first cuboids and an octahedron, the two first cuboids are respectively integrated with the side surfaces of the octahedron, are both located on the top of the substrate, and are symmetrically arranged with respect to the octahedron.

[0008] Wherein, each of the first cuboids has a length of 150 nm and a width of 50 nm.

[0009] Each of the octahedrons includes two tetrahedrons and a second cuboid, and the two tetrahedrons are respectively integrated with the side surfaces of the second cuboid and are respectively located between the second cuboid and the corresponding first cuboid.

[0010] The cross section of each tetrahedron is a trapezoid, the upper base of the trapezoid is 50nm, the lower base is 90nm, and the height is 100nm;

[0011] The second cuboid has a length of 90 nm and a width of 50 nm.

[0012] Wherein, the period of periodic distribution of a plurality of similar supersurface structures along the X direction is 900nm;

[0013] The period of periodic distribution of a plurality of similar supersurface structures along the Y direction is 200 nm.

[0014] The beneficial effects of the invention are as follows: the transmission intensity of the -1 order and the +1 order of the ultra-wideband wide-angle beam splitter based on the same metasurface structure is always kept equal within the working band. In the range of 678 to 833 nm, the transmittance of the ±1 diffraction order can be maintained above 35%, the total transmittance is greater than 74%, the +1 order transmittance is greater than 35%, and the deflection angle can reach 48.88° to 67.75°. At most wavelengths within the working band, the phase of the transmitted light of the ultra-wideband wide-angle beam splitter based on the same metasurface structure can maintain a phase difference of π, thereby realizing ultra-wideband equal power beam splitting. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 It is a structural schematic diagram of an ultra-wideband large-angle beam splitter based on a similar metasurface structure of the present invention.

[0017] Figure 2 It is a top view of the ultra-wideband large-angle beam splitter based on the same type of metasurface structure of the present invention.

[0018] Figure 3 It is the transmission spectrum of the ultra-wideband large-angle beam splitter based on the same type of super surface structure at -1, 0 and +1 orders and the total transmission spectrum of the present invention.

[0019] Figure 4 It is the transmission spectrum and deflection angle of the ultra-wideband large-angle beam splitter based on the same type of supersurface structure at the +1 order of the present invention.

[0020] Figure 5 It is a schematic diagram of the phase distribution along the x-direction of the ultra-wideband large-angle beam splitter based on the same type of metasurface structure of the present invention when the wavelength is 705nm.

[0021] Figure 6 It is a schematic diagram of the electric field distribution of the xz cross section of the ultra-wideband large-angle beam splitter based on the same type of supersurface structure of the present invention when the wavelength is 705nm.

[0022] Figure 7 It is a schematic diagram of the phase distribution along the x-direction at different wavelengths of the ultra-wideband large-angle beam splitter based on the same type of metasurface structure of the present invention.

[0023] 1-substrate, 2-similar metasurface structure, 3-first cuboid, 4-octahedron, 5-tetrahedron, 6-second cuboid. DETAILED DESCRIPTION

[0024] Embodiments of the invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the invention, and should not be construed as limiting the invention.

[0025] In the description of the invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention. In addition, in the description of the invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0026] See also Figures 1 to 7 The present invention provides an ultra-wideband large-angle beam splitter based on a similar supersurface structure 2, comprising a substrate 1 and a plurality of similar supersurface structures 2, each of the similar supersurface structures 2 being fixedly connected to the substrate 1 and located on the top of the substrate 1, and the plurality of similar supersurface structures 2 being periodically distributed along the X direction and the Y direction.

[0027] Furthermore, the material of each of the similar super-surface structures 2 is Si, and the height is 190 nm;

[0028] The material of the substrate 1 is SiO 2 , height is 1000nm.

[0029] Furthermore, each of the similar metasurface structures 2 includes two first cuboids 3 and an octahedron 4. The two first cuboids 3 are respectively integrated with the side surfaces of the octahedron 4, and are both located on the top of the substrate 1 and symmetrically arranged about the octahedron 4.

[0030] Furthermore, each of the first cuboids 3 has a length of 150 nm and a width of 50 nm.

[0031] Furthermore, each of the octahedrons 4 includes two tetrahedrons 5 and a second cuboid 6 , and the two tetrahedrons 5 are respectively integrated with the side surfaces of the second cuboid 6 , and are respectively located between the second cuboid 6 and the corresponding first cuboid 3 .

[0032] Furthermore, the cross section of each tetrahedron 5 is a trapezoid, the upper base of the trapezoid is 50nm, the lower base is 90nm, and the height is 100nm;

[0033] The second cuboid 6 has a length of 90 nm and a width of 50 nm.

[0034] Furthermore, the period of the periodic distribution of a plurality of similar supersurface structures 2 along the X direction is 900 nm;

[0035] The period of the periodic distribution of a plurality of similar supersurface structures 2 along the Y direction is 200 nm.

[0036] Specifically, the ultra-wideband large-angle beam splitter based on the similar metasurface structure 2 is a periodic arrangement of nanoparticles, which can be easily realized through nano-processing technology. The similar metasurface structure 2 is composed of a plurality of polyhedrons, and the periodic arrangement of such structures constitutes a similar metasurface. The geometric structure is changed while observing the intensity of the transmitted light passing through the similar metasurface, thereby obtaining the optimized parameters:

[0037] The material of each of the similar super surface structures 2 is Si, and the height is 190nm;

[0038] The length L of each of the first cuboids 3 is 1 Both are 150nm, width W 1 All are 50nm;

[0039] The cross section of each tetrahedron 5 is a trapezoid, and the upper base W of the trapezoid is 1 50nm, bottom W 2 Length 90nm, high L 2 100nm;

[0040] The length W of the second cuboid 6 is 2 90nm, width L 3 50nm;

[0041] The period P of a plurality of similar super-surface structures 2 periodically distributed along the X direction is x 900nm;

[0042] The period P of a plurality of similar super-surface structures 2 distributed periodically along the Y direction is y is 200nm.

[0043] Figure 3 The transmission spectra of -1, 0, and +1 orders and the total transmission spectrum of the ultra-wideband large-angle beam splitter based on the same metasurface structure 2 are given. The transmission intensity of -1 order and +1 order always remains equal in the working band. In the range of 678-833nm, the transmittance of ±1 diffraction order can be maintained above 35%, and the total transmittance is greater than 74%.

[0044] Figure 4 The +1 order transmission spectrum and deflection angle of the ultra-wideband large-angle beam splitter based on the similar metasurface structure 2 are given. In the range of 678 to 833 nm, the +1 order transmittance is greater than 35%, and the deflection angle can reach 48.88° to 67.75°.

[0045] Figure 5 A schematic diagram of the phase distribution along the x-direction of the ultra-wideband large-angle beam splitter based on the similar metasurface structure 2 is given when the wavelength is 705nm. The phase of the transmitted light is distributed 0-π-0 along the x-direction, which is the main reason why the ultra-wideband large-angle beam splitter based on the similar metasurface structure 2 can achieve equal-power beam splitting.

[0046] Figure 6 A schematic diagram of the electric field distribution of the xz cross section of the ultra-wideband large-angle beam splitter based on the similar metasurface structure 2 at a wavelength of 705 nm is given. The transmitted light is divided into two parts and emitted at the same angle along both sides of the normal.

[0047] Figure 7 A schematic diagram of the phase distribution along the x-direction of the ultra-wideband wide-angle beam splitter based on the same metasurface structure 2 at different wavelengths is given. The phase of the transmitted light of most wavelengths in the working band can maintain a phase difference of π. Therefore, the ultra-wideband wide-angle beam splitter based on the same metasurface structure 2 can achieve ultra-wideband equal-power beam splitting.

[0048] The above disclosure is only a preferred embodiment of the invention, which certainly cannot be used to limit the scope of the invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the invention still fall within the scope of the invention.

Claims

1. An ultra-wideband, wide-angle beam splitter based on the same metasurface structure, It is characterized in that It comprises a substrate and a plurality of similar super-surface structures, each of which is fixedly connected to the substrate and located on the top of the substrate, and the plurality of similar super-surface structures are periodically distributed along the X direction and the Y direction; The ultra-wideband large-angle beam splitter based on the similar metasurface structure is a periodic arrangement of nanoparticles, which is realized by nano-processing technology; the similar metasurface structure is composed of a plurality of polyhedrons, and the similar metasurface is formed by the periodic arrangement of such structures, and the intensity of the transmitted light passing through the similar metasurface is observed while changing the geometric structure, so as to obtain the optimized parameters; The material of each similar super surface structure is Si, and the height is 190nm; the material of the substrate is SiO 2 , height is 1000nm; Each of the similar supersurface structures comprises two first cuboids and an octahedron, wherein the two first cuboids are respectively integrated with the side surfaces of the octahedron, are both located on the top of the substrate, and are symmetrically arranged with respect to the octahedron; Each of the first cuboids has a length of 150 nm and a width of 50 nm; Each of the octahedrons includes two tetrahedrons and a second cuboid, and the two tetrahedrons are respectively integrated with the side surfaces of the second cuboid and are respectively located between the second cuboid and the corresponding first cuboid; The cross section of each tetrahedron is a trapezoid, the upper base of the trapezoid is 50nm, the lower base is 90nm long, and the height is 100nm; The second cuboid has a length of 90 nm and a width of 50 nm; The period of the periodic distribution of a plurality of similar supersurface structures along the X direction is 900 nm; The period of periodic distribution of a plurality of similar supersurface structures along the Y direction is 200 nm.

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