CN115047432A

CN115047432A - Double-spectrum super-surface and point cloud generating device and laser radar transmitting system

Info

Publication number: CN115047432A
Application number: CN202110257566.2A
Authority: CN
Inventors: 郝成龙; 谭凤泽; 朱健
Original assignee: Shenzhen Metalenx Technology Co Ltd
Current assignee: Shenzhen Metalenx Technology Co Ltd
Priority date: 2021-03-09
Filing date: 2021-03-09
Publication date: 2022-09-13

Abstract

The invention provides a double-spectrum super-surface, double-spectrum collimation-point cloud/multi-line generation device and a laser radar emission system comprising the same, wherein the double-spectrum super-surface is arranged on the same surface and comprises a plurality of super-surface structure units which are arranged in an array shape, and a nano structure is arranged at the central position of each super-surface structure unit or at the central position and the vertex position of each super-surface structure unit; the super-surface structure unit can efficiently transmit light with different wave bands, wherein the light with different wave bands comprises near infrared light 930 and 950nm and near infrared light 1530 and 1570 nm. A dual-spectrum collimation-point cloud/multi-line generation device and a laser radar transmitting system integrate a collimation system and a diffraction optical element, including the point cloud and the multi-line generation device, on a single device, and have the advantages of simple structure, light weight, small volume and easy integration.

Description

Double-spectrum super-surface and point cloud generating device and laser radar transmitting system

Technical Field

The invention relates to the field of super-surface devices, in particular to a double-spectrum super-surface, double-spectrum collimation-point cloud/multi-line generation device and a laser radar transmitting system.

Background

The laser radar plays an important role as a basic component in the scientific and industrial fields of automobile automatic driving, precise modeling, three-dimensional remote sensing and the like. The traditional laser radar transmitting system consists of a single-wavelength laser, a collimating lens and a diffraction optical element (used for generating point clouds). However, the conventional lidar transmitting system has the disadvantages of large volume, heavy weight, complex structure, incapability of distinguishing the materials of objects and the like.

Disclosure of Invention

In view of the above technical problems, embodiments of the present invention provide a dual-spectrum super-surface, dual-spectrum collimation-point cloud/multiline generation device and a laser radar transmission system including the same.

The first aspect of the embodiments of the present invention provides a dual-spectrum super-surface, which is disposed on a same surface, and includes a plurality of super-surface structure units arranged in an array, where a central position of each super-surface structure unit, or a central position and a vertex position of each super-surface structure unit, is provided with a nano-structure; the super-surface structure unit can efficiently transmit light with different wave bands, wherein the light with different wave bands comprises near infrared light 930 and 950nm and near infrared light 1530 and 1570 nm.

Optionally, the super-surface structure unit is a regular hexagon and/or a square;

when the incident light is polarized light or unpolarized light, the nano-structures on the double-spectrum super-surface are respectively axisymmetric along a first axis and a second axis, and a plurality of nano-structure units obtained by cutting the nano-structures along the first axis and the second axis are the same, wherein the first axis and the second axis are vertical, and the first axis and the second axis are respectively vertical to the height direction of the nano-structures; the nanostructures at different positions differ in optical phase at different wavelengths.

A second aspect of embodiments of the present invention provides a dual spectral collimation-point cloud/multiline generation device, comprising:

a substrate having high transmittance in both spectra;

the dual-spectrum super-surface is arranged on two sides of the substrate, wherein one side close to the light source is a collimation super-surface which is used for diverging light velocity of the laser light source; wherein the side remote from the light source generates a super-surface for the point cloud/multiline which is used to generate the point cloud/multiline in the far field.

Optionally, the substrate is quartz glass, schottky glass or crown glass, and the thickness of the substrate is 0.1mm to 10 mm.

Optionally, the phase of the collimating metasurface satisfies:

wherein the content of the first and second substances,

the phase distribution of the collimating super-surface to the first near-infrared light, r is the position of the collimating super-surface along the radius direction, and lambda ₁ In the near infrared light 930- ₁ A focal length of the collimating meta-surface to the first near-infrared light;

the phase distribution of the collimating super-surface to the second near-infrared light, r is the position of the collimating super-surface along the radius direction, and lambda ₂ In the near infrared light of 1530-1570nm, f ₂ To collimate the focal length of the hyper-surface to the second near-infrared light.

Optionally, the point cloud/multiline produces a phase distribution of the super-surface determined by the far-field point cloud/multiline distribution, which can be computed by the Gerchberg-Saxton iterative algorithm.

The double-spectrum collimation-point cloud/multi-line generation device integrates a collimation system and a diffraction optical element (point cloud/multi-line generation device) into a single device, and has the advantages of simple structure, light weight, small volume and easiness in integration.

A third aspect of an embodiment of the present invention provides a laser radar transmission system, including:

two lasers with center wavelengths of 940nm and 1550nm respectively;

a dichroic mirror;

a set of scanning systems; and

a dual spectral collimation-point cloud/multiline generator as described in any one of the above.

Optionally, a light source of the laser is a point light source, and a divergence angle after collimation is 1 mrad-5 mrad; or the light source of the laser is a surface light source, and the divergence angle is 1mrad multiplied by 1mrad to 5mrad multiplied by 5mrad after collimation.

Optionally, the number of points projected by the laser radar transmitting system in a far field is 100-1000000; the number of lines projected by the laser radar transmitting system in a far field is 16-1024.

Optionally, the scanning system is insensitive to laser wavelength; the scanning system is a mechanical reflection scanning mirror or an MEMS reflection galvanometer.

According to the technical scheme provided by the embodiment of the invention, the laser radar transmitting system integrates the collimation system and the diffraction optical element (point cloud/multi-line generating device) into a single device, so that the laser radar transmitting system has the advantages of simple structure, light weight, small volume and easiness in integration.

In addition, the laser radar transmitting system has double-spectrum transmitting capability, and compared with the existing laser radar transmitting system, the optical system of the laser radar transmitting system has the capability of detecting different materials.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Drawings

FIG. 1A is a diagram of a regular hexagonal arrangement of a super-surface in one embodiment of the present invention;

FIG. 1B is a diagram illustrating a square arrangement of a super-surface in one embodiment of the present invention;

FIG. 2A is a schematic diagram of a positive nanorod structure, in one embodiment of the invention;

FIG. 2B is a schematic diagram of a negative nanorod structure, in accordance with an embodiment of the invention;

FIG. 2C is a schematic diagram of a hollow nanopillar structure in an embodiment of the invention;

FIG. 2D is a schematic diagram of a negative hollow nanorod structure, in accordance with an embodiment of the invention;

FIG. 2E is a schematic diagram of a square nano-pillar structure in an embodiment of the invention;

FIG. 2F is a schematic view of a negative-square nanorod structure, in accordance with an embodiment of the invention;

FIG. 2G is a schematic diagram of a hollow square nanorod structure, according to an embodiment of the invention;

FIG. 2H is a schematic diagram of a negative hollow square nanorod structure, according to an embodiment of the invention;

FIG. 2I is a schematic diagram of a topological nanopillar structure in an embodiment of the present invention;

FIG. 3A is a graph of the optical phase at an operating wavelength of 940nm versus the diameter of a nano-pillar structure of a quartz substrate and amorphous silicon material in an embodiment of the present invention;

FIG. 3B is a graph of light transmittance at an operating wavelength of 940nm as a function of nanorod structure diameter for a quartz substrate and amorphous silicon material in accordance with an embodiment of the invention;

FIG. 3C is a graph of optical phase at an operating wavelength of 1550nm as a function of nanorod structure diameter of a quartz substrate and amorphous silicon material, in accordance with an embodiment of the invention;

FIG. 3D is a graph of the optical transmission at 1550nm operating wavelength as a function of the diameter of the nano-pillar structures of a quartz substrate and amorphous silicon material in an embodiment of the invention.

FIG. 4A is a schematic diagram of a dual spectrum collimation-point cloud/multiline generation device in accordance with an embodiment of the present invention;

FIG. 4B is a flow chart of phase iterative computation for a dual spectral alignment-point cloud/multiline generation device in an embodiment of the present invention;

FIG. 5A is a schematic diagram of a lidar transmission system in an embodiment of the invention;

FIG. 5B is a schematic diagram of a lidar transmission system in another embodiment of the invention;

FIG. 6A is a graph of optical phase at 940nm versus superlens radius for a collimated super-surface of a dual spectral collimation-point cloud/multiline generation device in the lidar transmission system shown in FIGS. 5A and 5B;

FIG. 6B is a graph of the optical phase at 1550nm of the collimating metalens versus the metalens radius for the dual spectral collimation-point cloud/multiline generation device of the lidar transmission system shown in FIGS. 5A and 5B;

FIG. 6C is a phase diagram of the point cloud (576 points) of the dual spectral collimation-point cloud/multiline generation device in the emission system of FIGS. 5A and 5B to generate a super-surface;

FIG. 6D is a phase diagram of a multi-line (64 lines) generating metasurface of the dual spectral collimation-point cloud/multi-line generating device in the emission system of FIGS. 5A and 5B;

FIG. 7 is a far field point cloud diagram of a lidar transmission system in an embodiment of the present invention;

FIG. 8 is a far field multi-line plot in a lidar transmission system in an embodiment of the present invention;

reference numerals:

100: dual spectral collimation-point cloud/multiline generation device; 1: a substrate; 11: collimating the super-surface; 12: point cloud/multiline generation of the super-surface;

2: a super-surface structure unit; 21: a nanostructure; 211: a positive nanorod structure; 212: a negative nanocolumn structure; 2121: a first column; 2122: a first hollow section; 213: a hollow nano-pillar structure; 2131: a second cylinder; 2132: a second hollow section; 214: a negative hollow nanocolumn structure; 2141: a second cylinder; 2412: a third hollow section; 2143: a third cylinder; 215: a square nano-pillar structure; 216: a negative square nanocolumn structure; 2161: a fourth cylinder; 2162: a fourth hollow section; 217: a hollow square nano-pillar structure; 2171: a fifth cylinder; 2172: a fifth hollow section; 218: a negative hollow square nanocolumn structure; 2181: a sixth cylinder; 2182: a sixth hollow section; 2183: a seventh column; 219: a topological nanopillar structure;

31a, 31 b: a laser; 32: a dichroic mirror; 33: a scanning system.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited by these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present invention. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context. The features of the following examples and embodiments may be combined with each other without conflict.

The single-wavelength laser radar transmitting optical system composed of the collimating lens group and the diffractive optical element has the defects of complex structure, heavy weight, large volume and difficulty in integration. Moreover, the monochromatic laser radar cannot distinguish the material of the detected object. Meanwhile, the low-order diffractive optical element has low diffraction efficiency, thereby causing the detection distance of the laser radar to be reduced.

Optical super-surfaces are rapidly emerging and becoming a mainstream way to achieve miniaturized, planarized optics. Optical super-surfaces have demonstrated super-surface based axicons, blazed gratings, polarizers, holographic dry plates and planar lenses. The continuous 2 pi phase change metasurface makes a single layer aspherical superlens a reality. At the same time, achromatic metasurfaces are also used for white light imaging.

The first embodiment is as follows:

the first aspect of the embodiment of the present invention provides a dual-spectrum super surface, which is disposed on the same surface, and includes a plurality of super surface structure units 2 arranged in an array, where a central position of each super surface structure unit 2, or a central position and a vertex position of each super surface structure unit 2, are respectively provided with a nano structure 21; the super-surface structure unit 2 can efficiently transmit light of different wavelength bands, wherein the light of different wavelength bands comprises near infrared light 930 and 950nm and near infrared light 1530 and 1570 nm. The dual-spectrum super-surface may be specifically provided on one or both sides of the substrate 1.

Specifically, the super-surface structure unit 2 is a regular hexagon and/or a square; when the incident light is polarized light or unpolarized light, the nano-structures 21 on the dual-spectrum super-surface are respectively axisymmetric along a first axis and a second axis, and a plurality of nano-structure units obtained by cutting the nano-structures 21 along the first axis and the second axis are the same, wherein the first axis and the second axis are vertical, and the first axis and the second axis are respectively vertical to the height direction of the nano-structures 21; the nanostructures 21 at different positions differ in the phase of light at different wavelengths.

For example, referring to fig. 1A, a nano structure 21 is respectively disposed at a central position of each super-surface structure unit, and such an array arrangement results in a minimum number of nano structures 21 of the formed dual-spectrum super-surface, and the performance of the formed dual-spectrum super-surface also meets the requirement; illustratively, referring to fig. 1B, the vertex position of each super surface structure unit 2 and the center position of each super surface structure unit are respectively provided with one nano structure 21.

Illustratively, in some embodiments, referring to fig. 1A, all of the super surface structure units 2 are regular hexagons; in other embodiments, referring to fig. 1B, all the units 2 of the super-surface structure are square; in other embodiments, the plurality of super surface structure units 2 includes regular hexagonal array units and square super surface structure units 2. It should be understood that in other embodiments, the super-surface structure unit 2 may be designed in other regular polygonal or fan-shaped structures.

In this embodiment, the nano-structure 21 has an average transmittance of more than 80% at 930-.

In this embodiment, the nanostructures 21 are axisymmetric along the first axis and the second axis, and a plurality of nanostructure units obtained by splitting the nanostructures 21 along the first axis and the second axis are the same, and such a structure is not sensitive to the polarization of incident light. Wherein the first axis and the second axis are perpendicular, and the first axis and the second axis are respectively perpendicular to the height direction of the nano structure. It should be noted that the first axis and the second axis pass through the center of the nanostructure 21 and are parallel to the horizontal plane.

In this embodiment, the optical phase of the nanostructures 21 at different wavelengths is different at different positions, so as to define the optical phase distribution of the meta-surface at different wavelengths. It should be noted that the plurality of nanostructures 21 of the embodiment of the present application form an integral structure that can simultaneously transmit near infrared light in the dual band.

Illustratively, the material of the nano-structure 21 may be quartz glass, crystalline silicon or amorphous silicon; it should be understood that other nanopillars may be used.

For example, the nano-structure 21 may be a nano-pillar structure, or may be other nano-structures that are axisymmetric along a horizontal axis and a vertical axis, respectively.

Next, the nano-structure 21 is explained as an example of a nano-pillar structure; it should be understood that when the nano-structure 21 is other structure, the nano-pillar structure may be replaced with a corresponding structure in the following embodiments.

The nanopillar structure may include at least one of a positive nanopillar structure 211, a negative nanopillar structure 212, a hollow nanopillar structure 213, a negative hollow nanopillar structure 214, a square nanopillar structure 215, a negative square nanopillar structure 216, a hollow square nanopillar structure 217, a negative hollow square nanopillar structure 218, and a topological nanopillar structure 219. Illustratively, the nano-pillar structure is one of a positive nano-pillar structure 211, a negative nano-pillar structure 212, a hollow nano-pillar structure 213, a negative hollow nano-pillar structure 214, a square nano-pillar structure 215, a negative square nano-pillar structure 216, a hollow square nano-pillar structure 217, a negative hollow square nano-pillar structure 218, and a topological nano-pillar structure 219, which facilitates processing.

In the embodiment of the present application, the optical phase of the nano-structure, the height of the nano-pillar structure, the shape of the cross section, and the material of the nano-pillar structure.

Referring to fig. 2A to 2I, the height of the nano-pillar structure (i.e., the height of the nano-pillar structure in the z direction) is H.

The height H of the nanopillar structure is greater than or equal to 300nm and less than or equal to 3500nm, the interval between adjacent nanopillar structures (i.e., the interval between the centers of two adjacent nanopillar structures) is greater than or equal to 40nm and less than or equal to 640nm, and the minimum dimension of the nanopillar structure and the minimum interval between two adjacent nanopillar structures (i.e., the minimum distance between the edges of two adjacent nanopillars) may be 40 nm. Illustratively, the height H of the nanopillar structure is 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, 1100nm, 1200nm, 1300nm, 1400nm, 2500nm, 3500nm, or the like. Illustratively, the spacing between adjacent nanopillar structures is 40nm, 140nm, 240nm, 340nm, 440nm, 540nm, or 640nm, among others.

Referring to fig. 2A, the positive nanorod structures 211 may include a first cylinder, which is a solid structure. The positive nanorod structures 211 have a cross-sectional diameter d in the x-y plane in a range between 40nm and 600nm, e.g., d may be set at 40nm, 50nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 500nm, 600nm, etc.

Referring to fig. 2B, the negative nanorod structures 212 may include first pillars 2121, wherein the cross-sectional shape of the first pillars 2121 is the same as that of the super-surface structure unit 2, for example, when the super-surface structure unit 2 is a hexagon, the cross-sectional shape of the first pillars 2121 is a hexagon; when the super surface structure unit 2 is square, the shape of the cross section of the first pillar 2121 is also square. In this embodiment, the cross-section of the first cylinder 2121 has the same size as the super surface structure unit 2. The first cylinder 2121 is provided with a first hollow 2122 having a cylindrical shape extending from the top to the bottom thereof, and the first cylinder 2121 and the first hollow 2122 are coaxial. The negative nanorod structures 212 have a cross-sectional diameter d in the x-y plane (i.e., cross-section) in a range between 40nm and 600nm, e.g., d may be set at 40nm, 50nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 500nm, 600nm, etc.

Referring to fig. 2C, the hollow nano-pillar structure 213 may include a second cylinder 2131, the second cylinder 2131 is provided with a second hollow portion 2132 having a cylindrical shape extending from the top to the bottom thereof, and the second cylinder 2131 is coaxial with the second hollow portion 2132. The hollow nanorod structures 213 have a cross-sectional outer diameter d in the x-y plane ₁ And an inner diameter d ₂ ，d ₁ -d ₂ In the range of 40nm to 600nm, e.g. d ₁ -d ₂ May be set to 40nm, 50nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 500nm, 600nm, etc.

Referring to fig. 2D, the negative hollow nano-pillar structure 214 may include a second pillar 2141, wherein the shape of the cross section of the second pillar 2141 is the same as the shape of the super surface structure unit 2, for example, when the super surface structure unit 2 is a hexagon, the shape of the cross section of the second pillar 2141 is also a hexagon; when the super surface structure unit 2 is square, the shape of the cross section of the second pillar 2141 is also square. In the present embodiment, the size of the cross section of the second pillar 2141 is the same as the size of the super surface structure unit 2. Further, the second cylinder 2141 is provided with a cylindrical third hollow portion 2142 extending from the top to the bottom thereof. Further, a third cylinder 2143 is disposed inside the third hollow portion 2142, and the third cylinder 2143 is a solid structure. The second cylinder 2141, the third hollow portion 2142 and the third cylinder 2143 are coaxial, the height of the second cylinder 2141 is equal to that of the third cylinder 2143, and the bottom of the third cylinder 2143 is attached to the substrate 1.

Referring to fig. 2E, the square nano-pillar structure 215 may include a third pillar, the third pillar is a solid structure, and the cross section of the third pillar has a square shape.

Referring to fig. 2F, the negative-side nano-pillar structure 216 may include a fourth pillar 2161, and the cross-sectional shape of the fourth pillar 2161 is the same as that of the super surface structure unit 2, for example, when the super surface structure unit 2 is a hexagon, the cross-sectional shape of the fourth pillar 2161 is a hexagon; when the super surface structure unit 2 is square, the cross-sectional shape of the fourth pillar 2161 is also square. In this embodiment, the size of the cross-section of the fourth pillar 2161 is the same as the size of the super surface structure unit 2. Further, the fourth column 2161 is provided with a fourth hollow portion 2162 extending from the top to the bottom thereof, the cross-section of the fourth hollow portion 2162 is square, and the fourth column 2161 is coaxial with the fourth middle portion.

Referring to fig. 2G, the hollow square nanorod structure 217 may include a fifth cylinder 2171, and the cross-section of the fifth cylinder 2171 has a square shape. Further, the fifth cylinder 2171 is provided with a fifth hollow 2172 extending from the top to the bottom thereof, and the cross section of the fifth hollow 2172 is square in shape. And, the fifth cylinder 2171 is coaxial with the fifth hollow 2172. In the same cross section, the corresponding square of the fifth cylinder 2171 is collinear with the corresponding diagonal of the corresponding square of the fifth hollow 2172.

Referring to fig. 2H, the negative hollow square nanopillar structure 218 may include sixth pillars 2181, a cross-sectional shape of the sixth pillars 2181 is the same as a shape of the super surface structure unit 2, for example, when the super surface structure unit 2 is a hexagon, a cross-sectional shape of the sixth pillars 2181 is a hexagon; when the super surface structure unit 2 is square, the cross-sectional shape of the sixth column 2181 is also square. In this embodiment, the size of the cross section of the sixth cylinder 2181 is the same as that of the super surface structure unit 2. Further, the sixth cylinder 2181 is provided with a sixth hollow part 2182 extending from the top to the bottom thereof, and the sixth hollow part 2182 has a square shape in cross section. A seventh cylinder 2183 is disposed inside the sixth hollow portion 2182, the seventh cylinder 2183 is a solid structure, and the cross section of the seventh cylinder 2183 is square. In this embodiment, the sixth cylinder 2181, the sixth hollow portion 2182 and the seventh cylinder 2183 are coaxial. In addition, on the same cross section, the corresponding diagonal lines of the square corresponding to the seventh cylinder 2183 and the square corresponding to the sixth hollow part 2182 are collinear.

Referring to fig. 2I, the topological nanorod structure 219 may include an eighth pillar, and the eighth pillar is a solid structure. And the cross section of the eighth cylinder is polygonal, and the sides of the polygon are arc-shaped.

Illustratively, in certain embodiments, the nano-pillar structures are round nano-pillar structures. For the design work at near infrared wavelength 940nm, the material of the circular nano-pillar structure is amorphous silicon, the positive nano-pillar structure adopts the positive nano-pillar structure shown in fig. 2A, the height H of the positive nano-pillar structure is 1600nm, and the edge of the corresponding regular hexagon basic unit is 405 nm. Fig. 3A shows the relationship between the near infrared wavelength 940nm and the optical phase of the super-surface and the diameter of the positive nanorod structure, where in fig. 3A, the abscissa is the diameter of the positive nanorod structure and the ordinate is the optical phase at 940 nm. Fig. 3B shows the relationship between the near infrared wavelength of 940nm and the transmittance of the super-surface and the diameter of the positive nanorod structure, where in fig. 3B, the abscissa is the diameter of the positive nanorod structure and the ordinate is the optical phase at 940 nm. FIG. 3C shows the near infrared wavelength of 1550nm, the optical phase of the super-surface as a function of the diameter of the positive nanorod structures, on FIG. 3C, the abscissa is the diameter of the positive nanorod structures and the optical phase at 1550nm on the ordinate. FIG. 3D shows the relationship between the transmittance of the super-surface and the diameter of the positive nanorod structures at a near infrared wavelength of 1550nm, with the abscissa of the graph in FIG. 3D being the diameter of the positive nanorod structures and the ordinate of the optical phase at 1550 nm.

The second embodiment:

a second aspect of the embodiment of the present invention provides a dual spectrum collimation-point cloud/multi-line generation device 100, please refer to fig. 4A, which includes: a substrate 1 having high transmittance in both spectra; the dual-spectrum super-surface is arranged on two surfaces of the substrate 1, wherein one surface close to the light source is a collimation super-surface 11 which is used for diverging light velocity of the laser light source; wherein the side remote from the light source is the point cloud/multiline generating super surface 12 which is used to generate the point cloud/multiline in the far field, as the diffractive optical element in a conventional lidar functions.

Optionally, the substrate 1 is quartz glass, schottky glass or crown glass, and the thickness of the substrate 1 is 0.1mm to 10 mm. Illustratively, the substrate material is a first near-infrared light and second near-infrared light high-transmittance material, such as quartz glass, K9 glass, and the like. The thickness of the substrate is between 0.1mm and 10mm, and the thickness can be set to 0.1mm, 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc.

Illustratively, the phase of the collimating super-surface 12 satisfies:

wherein, the first and the second end of the pipe are connected with each other,

for the phase distribution of the collimating super-surface 11 to the first near-infrared light, r is the position of the collimating super-surface 11 in the radial direction, λ ₁ In the near infrared light 930- ₁ Is the focal length of the collimating meta-surface 11 to the first near infrared light;

for the phase distribution of the collimating super-surface 11 to the second near-infrared light, r is the position of the collimating super-surface 11 along the radial direction, λ ₂ In the near infrared light of 1530-1570nm, f ₂ To collimate the focal length of the meta-surface 11 to the second near-infrared light.

The point cloud/multiline generation phase distribution of the super-surface 12 is determined by the far field point cloud/multiline distribution, which can be calculated by the Gerchberg-Saxton iterative algorithm.

Example three:

the central wavelengths of the two

lasers

31a and 31b are 940nm and 1550nm respectively;

a dichroic mirror 32;

a set of scanning systems 33; and

a dual spectral collimation-point cloud/multiline generator 100 as described in any one of the above.

Compared with the existing laser radar transmitting system, the laser radar transmitting system of the invention has the advantages of simple structure, small volume, light weight, easy integration and capability of distinguishing the material of the detected object by using the double-spectrum collimation-point cloud/multi-line generator 100.

Optionally, the light sources of the

lasers

31a and 31b may be point light sources, and the divergence angle after collimation is 1mrad to 5 mrad; or the light sources of the

lasers

31a and 31b can be surface light sources, and the divergence angle after collimation is 1mrad multiplied by 1mrad to 5mrad multiplied by 5 mrad.

In particular, the scanning system 33 is insensitive to the laser wavelength; the scanning system 33 may be a mechanical reflective scanning mirror or a MEMS mirror.

For example, please refer to fig. 5A and 5B, wherein fig. 5A is a schematic diagram of a laser radar transmitting system when the scanning system 33 is a mechanical reflective scanning mirror, and fig. 5B is a schematic diagram of a laser radar transmitting system when the scanning system 33 is an MEMS reflective galvanometer.

Illustratively, the 940nm lasers are all vertical cavity surface emitting lasers, the light emitting region is a circle with a diameter of 0.36mm, and the divergence angle is 24 °; on the other hand, the 1550nm lasers are all vertical cavity surface emitting lasers, and the light emitting region is a circle having a diameter of 0.36mm and has a divergence angle of 24 °. The focal length of the collimating super-surface 11 for 940nm and 1550nm are both 120mm, the diameter of the collimating super-surface 11 is 50.8mm (2 inches), and the phase distribution of the collimating super-surface can be calculated according to equation (1). 940nm and 1550nm phase distributions are shown in fig. 6A and 6B, respectively, where the solid line is the theoretically calculated phase and "×" is the phase of light emitted from the nanostructure searched the nano-database at 940nm and 1550nm, respectively. The substrate 1 is made of quartz glass and has a thickness of 5 mm. After collimation, the divergence angles of the 940nm and 1550nm light are both 3 mrad.

Illustratively, the phase map required for the far field 576 point cloud may be obtained by iterative Gerchberg-Saxton calculations with reference to the flow of fig. 4B, wherein,

which represents the fourier transform of the signal,

representing the inverse fourier transform, I is amplitude, phi is phase, a is complex amplitude; referring to FIG. 6C, where the point cloud produces a super surface with a side length of 50.8 mm; on the other hand, referring to the flow of FIG. 4B, the far field 64-line multiline required phase map can be obtained by iterative Gerchberg-Saxton calculation, referring to FIG. 6D, where the multilines produce a side length of 50.8mm of the super-surface.

Exemplary 576-point cloud plots of 940nm and 1550nm in the far field are shown in FIG. 7.

An exemplary 64 line plot of 940nm versus 1550nm in the far field is shown in FIG. 8.

Illustratively, when the scanning system 33 is a mechanical mirror scanner, specifically a biaxial mechanical field mirror scanner, the scan angle is 40 ° × 10 °, the scan frequency is 40 Hz; on the other hand, when the scanning system 33 is a MEMS mirror, specifically, a biaxial MEMS mirror, the scanning angle is 30 ° × 24 °, the fast axis scanning frequency is 25kHz, and the slow axis scanning frequency is 1.2 kHz.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A dual-spectrum super surface is arranged on the same surface and is characterized by comprising a plurality of super surface structure units which are arranged in an array shape, wherein a nano structure is arranged at the central position of each super surface structure unit or at the central position and the vertex position of each super surface structure unit; the super-surface structure unit can efficiently transmit light with different wave bands, wherein the light with different wave bands comprises near infrared light 930-950nm and near infrared light 1530-1570 nm.

2. The dual-spectrum metasurface of claim 1, wherein the metasurface structure units are regular hexagons and/or squares;

3. A dual spectral collimation-point cloud/multiline generation device comprising:

a substrate having high transmittance in both spectra;

the dual-spectrum super-surface of any one of claims 1 to 2, disposed on both sides of the substrate, wherein the side near the light source is a collimating super-surface for the divergent beam velocity of the laser light source; wherein the side remote from the light source generates a super-surface for the point cloud/multiline which is used to generate the point cloud/multiline in the far field.

4. The dual spectrum collimation-point cloud/multiline generation device of claim 3, wherein the substrate is quartz glass or schottky glass or crown glass, and the substrate has a thickness of 0.1mm to 10 mm.

5. The dual spectral collimation-point cloud/multiline generation device of claim 3 wherein the phase of the collimated super surface satisfies:

wherein the content of the first and second substances,

the phase distribution of the collimating super-surface to the first near-infrared light, r is the position of the collimating super-surface along the radius direction, and lambda ₁ In the near infrared light 930-950nm, f ₁ Is the focal length of the collimating super-surface to the first near infrared light;

the phase distribution of the collimating super-surface to the second near-infrared light, r is the position of the collimating super-surface along the radius direction, and lambda ₂ In the near infrared light of 1530-1570nm, f ₂ To collimate the focal length of the meta-surface to the second near-infrared light.

6. The dual spectral collimation-point cloud/multiline generation device of claim 3, wherein the phase distribution of the point cloud/multiline generation hyper-surface is determined by a far field point cloud/multiline distribution, which can be calculated by a Gerchberg-Saxton iterative algorithm.

7. A lidar transmission system, comprising:

two lasers with center wavelengths of 940nm and 1550nm respectively;

a dichroic mirror;

a set of scanning systems; and

a dual spectral collimation-point cloud/multiline generator as claimed in any one of claims 3 to 6.

8. The lidar transmission system of claim 7, wherein the light source of the laser is a point light source, and the divergence angle after collimation is 1mrad to 5 mrad; or the light source of the laser is a surface light source, and the divergence angle is 1mrad multiplied by 1mrad to 5mrad multiplied by 5mrad after collimation.

9. The lidar transmission system according to claim 7, wherein the number of points projected by the lidar transmission system in a far field is 100 to 1000000; the number of lines projected by the laser radar transmitting system in a far field is 16-1024.

10. The lidar transmission system of claim 7, wherein the scanning system is insensitive to laser wavelength; the scanning system is a mechanical reflection scanning mirror or an MEMS reflection galvanometer.