Superlens for projecting linear light spot and emission system

Abstract

The utility model provides a super lens for projecting a linear light spot and an emission system. The super lens provided by the utility model comprises a substrate and a micro-nano structure arranged on the substrate, the super lens is used for shaping incident light into a linear light beam, and the linear light beam is used for projecting on a target plane to obtain a linear light spot; the divergence angle of the incident light parallel to the line length direction of the linear light spot is smaller than or equal to the divergence angle of the incident light parallel to the line width direction of the linear light spot. According to the super lens provided by the invention, the direction of the incident light with a larger divergence angle is preferentially used as the parallel direction of the line width direction, so that the beam waist corresponding to the line width direction is effectively reduced, the lower limit of the line width is reduced, and the effective compression of the line width is facilitated.

Description

Technical Field

[0001] The present application relates to the field of optics, and in particular to a metalens and an emission system for projecting a line of light spots. Background Art

[0002] A line beam is a beam used to project a line of light onto a target plane, often used in scenarios such as 3D sensing and positioning identification. The line beam is in the shape of a straight line, with the direction parallel to its long side often referred to as the line length, and the direction parallel to its wide side often referred to as the line width. Generally, applications such as 3D sensing and positioning identification are primarily based on the intensity distribution of a line beam along its length.

[0003] For a metalens used to project a line of light, it is usually necessary to minimize the line width of the line of light. However, how to effectively compress the line width of the line of light output by the metalens is an urgent problem to be solved in this field. Utility Model Content

[0004] One objective of this application is to provide a metalens and emission system for projecting a line of light. The metalens provided in this application prioritizes the direction of incident light with a larger divergence angle as a parallel direction to the line width direction, effectively reducing the beam waist corresponding to the line width direction, thereby lowering the lower limit of the line width and facilitating effective line width compression.

[0005] According to one aspect of an embodiment of the present application, a metalens for projecting a line light spot is disclosed. The metalens includes a substrate and a micro-nanostructure provided on the substrate. The metalens is used to shape incident light into a line light beam, and the line light beam is used to project the line light spot onto a target plane.

[0006] The divergence angle of the incident light parallel to the line length direction of the word line light spot is less than or equal to the divergence angle of the incident light parallel to the line width direction of the word line light spot.

[0007] In an exemplary embodiment of the present application, the active area of ​​the metalens includes at least one first arched area and at least one second arched area;

[0008] The top of the first arched area faces the second arched area, and the top of the second arched area faces the first arched area.

[0009] In an exemplary embodiment of the present application, the first arched area and the second arched area are symmetrically distributed with respect to a target direction in a two-dimensional plane where the metalens is located, so that a line connecting the center of the line light spot and the center of the effective area is perpendicular to the metalens;

[0010] The target direction is perpendicular to the dome orientation of the dome region.

[0011] In an exemplary embodiment of the present application, the first arched area and the second arched area are asymmetrically distributed with respect to a target direction in a two-dimensional plane where the metalens is located, so that a line connecting the center of the line light spot and the center of the effective area is inclined with respect to the metalens;

[0012] The target direction is perpendicular to the dome orientation of the dome region.

[0013] In an exemplary embodiment of the present application, when the effective area includes at least two first areas, the tops of the first arched areas are oriented in the same direction, and the first arched areas are adjacent to each other in a concentric manner.

[0014] When the effective area includes at least two second areas, the tops of the second arched areas face the same direction, and the second arched areas are adjacent to each other in a concentric manner.

[0015] In an exemplary embodiment of the present application, when designing a shaping phase for shaping the incident light along the line length direction of the word-line light spot, in the target light intensity distribution of the word-line light beam, the number of light intensity data sampling points along the line length direction of the word-line light spot is N times the maximum number of micro-nano structures arranged along the one-dimensional direction in the metalens, and N is greater than or equal to 1.

[0016] In an exemplary embodiment of the present application, N is greater than or equal to 4.

[0017] According to one aspect of an embodiment of the present application, a method for designing a metalens for projecting a line of light spots is disclosed, the method comprising:

[0018] Obtaining an initial target light intensity distribution of the line-shaped light beam from design requirement information describing the performance of the line-shaped light beam, wherein the line-shaped light beam is used to project a line-shaped light spot on a target plane;

[0019] reconstructing the initial target light intensity distribution along the line length direction of the line light spot to obtain a reconstructed target light intensity distribution, wherein along the line length direction, the resolution of the reconstructed target light intensity distribution is higher than the resolution of the initial target light intensity distribution;

[0020] Based on the reconstructed target light intensity distribution and the light intensity distribution of the incident light received by the metalens, a shaping phase for shaping the incident light along the line length direction is designed;

[0021] Based on the shaping phase, the micro-nano structures that should be arranged at various positions on the metalens are determined, and the metalens for projecting the line light spot is designed.

[0022] In an exemplary embodiment of the present application, reconstructing the initial target light intensity distribution along the line length direction of the word line light spot to obtain the reconstructed target light intensity distribution includes:

[0023] extracting discrete light intensity data from the initial target light intensity distribution along the line length direction;

[0024] fitting, based on the discrete light intensity data, a light intensity distribution function for describing the initial target light intensity distribution along the line length direction;

[0025] The light intensity distribution function is discretized and valued to obtain the reconstructed target light intensity distribution.

[0026] In an exemplary embodiment of the present application, reconstructing the initial target light intensity distribution along the line length direction of the word line light spot to obtain the reconstructed target light intensity distribution includes:

[0027] extracting discrete light intensity data from the initial target light intensity distribution along the line length direction;

[0028] Interpolation processing is performed on the discrete light intensity data to obtain the reconstructed target light intensity distribution.

[0029] In an exemplary embodiment of the present application, based on the reconstructed target light intensity distribution and the light intensity distribution of the incident light received by the metalens, a shaping phase for shaping the incident light along the line length direction is designed, including:

[0030] Based on the law of conservation of energy, a one-to-one mapping is performed on the light intensity distribution of the incident light and the reconstructed target light intensity distribution along the line length direction, and based on the mapping result, a light beam exit angle at each position along the line length direction on the metalens is determined;

[0031] The shaping phase is calculated based on the light beam exit angle at each position along the line length direction on the metalens and the light beam incident angle at each position along the line length direction on the metalens.

[0032] In an exemplary embodiment of the present application, based on the reconstructed target light intensity distribution and the light intensity distribution of the incident light received by the metalens, a shaping phase for shaping the incident light along the line length direction is designed, including:

[0033] constructing the reconstructed target light intensity distribution along the line length direction into a target image used as a target output of a phase recovery algorithm;

[0034] Based on the light intensity distribution of the incident light along the line length direction and the target image, the phase recovery algorithm is applied to obtain the shaped phase.

[0035] In an exemplary embodiment of the present application, the method further includes:

[0036] Based on the distance between the metalens and the light source, a collimation phase is designed to collimate the incident light along the line length direction; the designed phase of the metalens includes the shaping phase and the collimation phase corresponding to the line length direction.

[0037] In an exemplary embodiment of the present application, the method further includes:

[0038] Obtaining a target line width of the single-line light spot from the design requirement information;

[0039] Based on the target line width and the intensity distribution of the incident light, a line width compression phase is designed to compress the line width of the single-line light spot along the line width direction; the designed phase of the metalens includes the shaping phase and the line width compression phase.

[0040] In an exemplary embodiment of the present application, the linewidth compression phase is a collimation phase along the linewidth direction, or a focusing phase along the linewidth direction.

[0041] According to one aspect of an embodiment of the present application, an emission system for projecting a line of light spots is disclosed, the emission system comprising: a light source; a metalens as provided in any of the above embodiments;

[0042] The super lens is arranged on the light-emitting side of the light source.

[0043] According to one aspect of an embodiment of the present application, an electronic device is disclosed, comprising: one or more processors; and a memory for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the electronic device implements any one of the above method embodiments.

[0044] According to one aspect of an embodiment of the present application, a computer-readable storage medium is disclosed, on which computer-readable instructions are stored. When the computer-readable instructions are executed by a processor of a computer, the computer is caused to execute any one of the above method embodiments.

[0045] In the embodiment of the present application, a metalens is used to shape the incident light into a line beam, which is used to project a line beam onto a target plane to obtain a line spot. The divergence angle of the incident light parallel to the line length direction of the line spot is less than or equal to the divergence angle of the incident light parallel to the line width direction of the line spot. In the embodiment of the present application, the direction with the larger divergence angle of the incident light is preferentially used as the parallel direction of the line width direction, thereby effectively reducing the beam waist corresponding to the line width direction and lowering the lower limit of the line width, thereby facilitating effective compression of the line width.

[0046] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by practice of the present application.

[0047] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and other objects, features and advantages of the present application will become more apparent by describing in detail example embodiments thereof with reference to the attached drawings.

[0049] Figure 1 Schematic diagram of the structure of the metalens provided in this application is shown.

[0050] Figure 2 A schematic diagram showing the composition of the effective area of ​​the metalens in one embodiment of the present application is shown.

[0051] Figure 3 FIG. 4 shows a phase distribution diagram of a metalens in an embodiment of the present application.

[0052] Figure 4 A schematic diagram showing the composition of the effective area of ​​the metalens in one embodiment of the present application is shown.

[0053] Figure 5 A schematic diagram showing the arrangement of micro-nano structures along a horizontal one-dimensional direction in an embodiment of the present application is shown.

[0054] Figure 6 A schematic diagram showing the arrangement of micro-nano structures along an inclined one-dimensional direction in an embodiment of the present application is shown.

[0055] Figure 7 A flow chart of a method for designing a metalens for projecting a line light spot provided in the present application is shown.

[0056] Figure 8 The figure shows a schematic diagram of the architecture of the emission system for projecting a line of light spots provided by the present application.

[0057] Figure 9The diagram shows a line light spot projected by a line light beam emitted by the line light beam emitting system of Example 1.

[0058] Figure 10 Shown Figure 9 The light intensity distribution curve of the line light spot in the line width direction is shown.

[0059] Figure 11 Shown Figure 9 The light intensity distribution curve of the line light spot in the line length direction is shown.

[0060] Figure 12 The diagram shows a line light spot projected by a line light beam emitted by the line light beam emitting system of Example 2.

[0061] Figure 13 Shown Figure 12 The light intensity distribution curve of the line light spot in the line width direction is shown.

[0062] Figure 14 Shown Figure 12 The light intensity distribution curve of the line light spot in the line length direction is shown.

[0063] Figure 15 The diagram shows a line light spot projected by a line light beam emitted by the line light beam emitting system of Example 3.

[0064] Figure 16 Shown Figure 15 The light intensity distribution curve of the line light spot in the line width direction is shown.

[0065] Figure 17 Shown Figure 15 The light intensity distribution curve of the line light spot in the line length direction is shown.

[0066] Figure 18 The light intensity distribution that the line light beam of Example 4 should satisfy along the line length direction is shown.

[0067] Figure 19 The diagram shows a line light spot projected by a line light beam emitted by the line light beam emitting system of Example 4.

[0068] Figure 20 Shown Figure 19 The light intensity distribution curve of the line light spot in the line width direction is shown.

[0069] Figure 21 Shown Figure 19 The light intensity distribution curve of the line light spot in the line length direction is shown.

[0070] Figure 22 A block diagram of a design device for a metalens provided in this application is shown. DETAILED DESCRIPTION

[0071] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of this application will be more comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The accompanying drawings are merely schematic illustrations of the present application and are not necessarily drawn to scale. Identical reference numerals in the figures indicate identical or similar parts, and thus repeated descriptions thereof will be omitted.

[0072] In addition, the described features, structures or characteristics may be combined in one or more example embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the example embodiments of the present application. However, those skilled in the art will appreciate that the technical solutions of the present application may be practiced while omitting one or more of the specific details, or other methods, components, steps, etc. may be adopted. In other cases, known structures, methods, implementations or operations are not shown or described in detail to avoid obscuring the main content and making various aspects of the present application vague.

[0073] Some of the blocks shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0074] On the surface, as long as the metalens converges the incident light along the line width direction of the line spot, as the degree of convergence increases, the line width of the line spot will become smaller and smaller until it is infinitely small. However, in fact, the incident light received by the metalens is usually from a laser light source. The light beam emitted by the laser light source has a corresponding waist size in all directions, and the beam waist corresponding to the line width direction determines the lower limit of the line width. Therefore, the line width of the line spot that can be output by the metalens cannot be compressed arbitrarily. Therefore, how to effectively compress the line width of the line spot that can be output by the metalens has become an urgent problem to be solved in this field.

[0075] To address the aforementioned issues, this application provides a metalens for projecting a line of light. By prioritizing the direction of incident light with a greater divergence angle as a parallel direction to the line width, the metalens provided in this application effectively reduces the beam waist corresponding to the line width direction, thereby lowering the lower limit of the line width and thus facilitating effective line width compression.

[0076] Figure 1Schematic diagram of the structure of the metalens provided by this application is shown. Figure 1 The metalens 1 provided in this application includes a substrate 11 and micro-nanostructures 12 disposed on the substrate 11. Each micro-nanostructure 12 can provide a certain phase for the received light beam, thereby causing the received light beam to produce a corresponding phase mutation. As a result, a certain phase gradient is generated at various positions on the metalens 1, thereby modulating the light beam at each position.

[0077] In the embodiment of the present application, the metalens 1 is used to shape the incident light into a line beam. After exiting the metalens 1, the line beam continues to propagate, and after propagating to a target plane 3 (e.g., a wall, the ground, etc.), it is projected onto the target plane 3 to obtain a line light spot 2. Figure 1 , the x-axis represents the line length direction of the line light spot 2 , the y-axis represents the line width direction of the line light spot 2 , and the z-axis represents the direction perpendicular to the super lens 2 .

[0078] It should be noted that, for a given incident light, the size of its beam waist in a specific direction is negatively correlated with the size of its divergence angle in that direction; that is, the larger the divergence angle of the incident light in a specific direction, the smaller the beam waist in that direction; conversely, the smaller the divergence angle of the incident light in a specific direction, the larger the beam waist in that direction.

[0079] As previously mentioned, the lower limit of the line width of the line spot 2 is actually determined by the beam waist corresponding to the line width direction; the smaller the beam waist corresponding to the line width direction, the smaller the lower limit of the line width of the line spot 2. Therefore, in the embodiment of the present application, the direction with a larger divergence angle of the incident light is preferentially used as the parallel direction to the line width direction, thereby effectively reducing the beam waist corresponding to the line width direction and lowering the lower limit of the line width, thereby facilitating effective compression of the line width.

[0080] Specifically, the incident light received by the metalens 1 may have different divergence angles in different directions, or may have the same divergence angle.

[0081] If the incident light has different divergence angles in different directions, the embodiment of the present application uses the direction with the larger divergence angle of the incident light as the parallel direction to the line width direction, thereby effectively reducing the beam waist corresponding to the line width direction and lowering the lower limit of the line width. Since the line width direction and the line length direction are two different directions (the line width direction and the line length direction are perpendicular to each other), when the direction with the larger divergence angle of the incident light is used as the parallel direction to the line width direction, the direction with the smaller divergence angle of the incident light becomes the parallel direction to the line length direction. Therefore, in this case, the divergence angle of the incident light parallel to the line length direction of the line spot 2 is smaller than the divergence angle of the incident light parallel to the line width direction of the line spot 2.

[0082] If the incident light has the same divergence angle in different directions, then the beam waist in each direction is equal. In the embodiment of the present application, any direction where the incident light diverges can be used as a direction parallel to the line width direction. In this case, the divergence angle of the incident light parallel to the line length direction of the line spot 2 is equal to the divergence angle of the incident light parallel to the line width direction of the line spot 2.

[0083] Figure 2 FIG2 is a schematic diagram showing the composition of the effective region of the metalens 1 in one embodiment of the present application. The effective region of the metalens 1 refers to the region in the metalens 1 where the micro-nanostructure 12 is provided to effectively phase modulate the light beam. Figure 2 The rectangular area in the figure exemplarily represents the complete effective area of ​​a metalens 1. It should be noted that the rectangle is only an exemplary representation of an optional shape of the effective area of ​​the metalens 1 and does not limit the shape of the effective area of ​​the metalens 1 in this application.

[0084] See also Figure 2 In one embodiment, the effective area of ​​the metalens 1 includes at least one first arched area ( Figure 2 Three first arched regions are shown, namely regions 41a, 41b and 41c) and at least one second arched region ( Figure 2 Three second arched areas are shown, namely areas 42a, 42b, and 42c. The top of the first arched area faces the second arched area, and the top of the second arched area faces the first arched area. In other words, the tops of the first and second arched areas are arranged opposite each other.

[0085] It should be noted that the division between the first and second arched regions is determined based on the distribution characteristics of the micro-nanostructures 12. By organizing the positions and sizes of the various micro-nanostructures 12, the effective area of ​​the metalens 1 is divided into the first and second arched regions. Specifically, for the metalens 1 provided in this embodiment, the composition of the first and second arched regions can be intuitively observed from both its SEM (Scanning Electron Microscope) images and its phase distribution diagram.

[0086] Figure 3 1 shows a phase distribution diagram of the superlens 1 in one embodiment of the present application. Figure 3 Different colors in the image represent different phase values, and the mapping relationship between colors and phase values ​​is described by the bars on the right. Figure 3The phase distribution diagram shown intuitively shows that the effective area of ​​the corresponding metalens 1 includes two types of arched regions with their tops facing each other. The arched regions on the left can be recorded as first arched regions, and the arched regions on the right can be recorded as second arched regions.

[0087] In this embodiment, the main purpose of providing the first arched region and the second arched region with their tops facing each other within the effective area of ​​the superlens 1 is to precisely control the eccentricity of the line light spot 2 by controlling the symmetry between the first arched region and the second arched region.

[0088] Specifically, the symmetry between the first arched region and the second arched region describes the symmetry between the first arched region and the second arched region with respect to a target direction. The target direction is located in the two-dimensional plane where the metalens is located and is perpendicular to both the dome orientation of the first arched region and the dome orientation of the second arched region. Figure 2 In the embodiment, the top direction of the first arched area and the top direction of the second arched area are both parallel to Figure 2 The horizontal direction of , so the target direction is Figure 2 vertical direction.

[0089] The eccentricity of the line light spot describes the offset property of the line light spot 2 relative to the normal emission direction of the metalens 1. Connect the center of the line light spot 2 with the center of the effective area of ​​the metalens 1 to obtain the corresponding connecting line. If the connecting line is perpendicular to the metalens 1, it means that the line light spot has not deviated from the normal emission direction of the metalens 1 and is an uneccentric line light spot; if the connecting line is inclined to the metalens 1, it means that the line light spot has deviated from the normal emission direction of the metalens 1 and is an eccentric line light spot. Moreover, the larger the inclination angle, the greater the degree of eccentricity.

[0090] like Figure 2 As shown, when the first arched area and the second arched area are symmetrically distributed about the target direction, the line connecting the center of the linear light spot 2 projected by the metalens 1 and the center of the effective area is perpendicular to the metalens 1; that is, when the first arched area and the second arched area are symmetrically distributed about the target direction, the linear light spot 2 projected by the metalens 1 is not decentered.

[0091] Figure 4 A schematic diagram showing the composition of the effective area of ​​the metalens in one embodiment of the present application is shown. Figure 4 There are two first arched areas, namely areas 41a and 41b, and three second arched areas, namely areas 42a, 42b and 42c; Figure 4 , the first arched area and the second arched area are about the target direction (ie, Figure 4 The vertical direction in the figure is asymmetrically distributed.

[0092] like Figure 4 As shown, when the first arched area and the second arched area are asymmetrically distributed with respect to the target direction, the line connecting the center of the linear light spot 2 projected by the metalens 1 and the center of the effective area is inclined with respect to the metalens 1; that is, when the first arched area and the second arched area are asymmetrically distributed with respect to the target direction, the metalens 1 projects an eccentric linear light spot 2.

[0093] Moreover, the greater the asymmetry between the first arched area and the second arched area with respect to the target direction, the greater the eccentricity of the line light spot 2 projected by the metalens 1 .

[0094] The first arched region is flipped about a target axis parallel to the target direction (the target axis does not intersect the first arched region) to obtain a symmetric region of the first arched region. Under the premise that the symmetric region of the first arched region can only be translated in a direction perpendicular to the target direction, the minimum difference that can be achieved between the geometric characteristics of the symmetric region of the first arched region and the geometric characteristics of the second arched region is determined; the greater the minimum difference, the greater the degree of asymmetry between the first arched region and the second arched region about the target direction.

[0095] The greater the inclination of the line connecting the center of the line light spot 2 and the center of the effective area relative to the super lens 1 , the greater the eccentricity of the line light spot 2 .

[0096] It can be seen that by arranging the first arch region and the second arch region with arch tops facing each other in the effective area of ​​the superlens 1, the eccentricity of the line light spot 2 can be accurately controlled by controlling the symmetry between the first arch region and the second arch region.

[0097] It should be noted that there may be only one or more first arched regions in the effective area of ​​the metalens 1; similarly, there may be only one or more second arched regions.

[0098] When there are multiple first arched areas in the effective area, the arch tops of the first arched areas are oriented in the same direction, and the first arched areas are adjacent to each other in a concentric manner. Figure 2 、 Figure 3 or Figure 4 As shown, in this case, the shape formed by all the first arched regions together is similar to a multi-layered rainbow shape or a multi-layered Swiss roll shape.

[0099] Similarly, when there are multiple second arched areas in the effective area, the arch tops of the second arched areas are oriented in the same direction, and the second arched areas are adjacent to each other in a concentric manner. Figure 2 、 Figure 3 or Figure 4As shown, in this case, the shape formed by all the second arched regions together is similar to a multi-layered rainbow shape or a multi-layered Swiss roll shape.

[0100] In order to design a metalens 1 for projecting a line light spot, it is necessary to first obtain the design requirement information, and then obtain the light intensity distribution requirements for the target line light beam from the design requirement information, that is, obtain the target light intensity distribution of the line light beam. Then, with the target light intensity distribution as the output target, the shaping phase of the metalens 1 is designed, and finally the metalens 1 is designed based on the shaping phase, so that the metalens 1 can shape the line light beam to obtain the target requirement. Among them, the shaping phase is used to shape the incident light along the line length direction of the line light spot 2; the shaped line light beam can then be projected to obtain the line light spot 2.

[0101] The phase of the metalens 1 refers to the set of phases of all micro-nanostructures 12 in the metalens 1. Therefore, determining the phase of the metalens 1 is to determine the phase of each micro-nanostructure 12 in the metalens 1.

[0102] If the positions of each micro-nanostructure 12 in the metalens 1 are observed separately, the sub-beams modulated at the positions of each micro-nanostructure 12 need to be propagated to a specific spatial position with a specific light intensity distribution, so that the sub-beams with a specific light intensity distribution at all specific spatial positions together constitute a line beam with a target light intensity distribution. Therefore, if the phase of each micro-nanostructure 12 is to be accurately determined, it is necessary to match each micro-nanostructure 12 as accurately as possible with the sub-beam with a specific light intensity distribution at the specific spatial position to which it should ultimately be modulated. In order to accurately design the shaping phase, it is necessary to match each micro-nanostructure 12 as accurately as possible with the sub-beam with a specific light intensity distribution at the specific spatial position to which it should ultimately be modulated along the line length direction of the line beam 2. Therefore, in the target light intensity distribution of the line beam, the number of light intensity data sampling points along the line length direction of the line beam 12 significantly affects the efficiency of the phase design.

[0103] Specifically, within the target intensity distribution of a line beam, the smaller the number of intensity data sampling points along the length of the line, the coarser and sparser the local intensity distributions that can be decomposed from the target intensity distribution. The coarser and sparser these local intensity distributions are, the more ambiguous the matching relationship between the micro-nanostructure 12 and the sub-beams with specific intensity distributions at specific spatial locations that it ultimately modulates will be at the initial stages of phase shaping design. This makes it more difficult to design an accurate phase shaping, resulting in lower phase design efficiency for the metalens 1.

[0104] Conversely, within the target intensity distribution of a line beam, the greater the number of intensity data sampling points along the length of the line, the finer and denser the local intensity distributions that can be decomposed from the target intensity distribution. The finer and denser these local intensity distributions are, the more precise the matching relationship between the micro-nanostructure 12 and the sub-beams with specific intensity distributions at specific spatial locations that it ultimately modulates will be during the initial stages of phase shaping design. This makes it easier to design an accurate shaping phase, thereby increasing the phase design efficiency of the metalens 1.

[0105] It should be noted that in related technologies, the target light intensity distribution directly used for phase design is the target light intensity distribution obtained from the design requirement information. However, in many cases, the target light intensity distribution obtained from the design requirement information is usually represented by an image—either by hand-drawing the image to show the light intensity curve corresponding to the target light intensity distribution along the length of the line, or by using drawing software to show the light intensity curve corresponding to the target light intensity distribution along the length of the line.

[0106] Limited by the resolution of pixels in the image, the target light intensity distribution obtained from the design requirement information, including the number of light intensity data sampling points along the length of the line, is far from meeting the requirements for efficient design of the shaping phase, which in turn leads to low phase design efficiency of the metalens in related technologies.

[0107] Therefore, in one embodiment, when designing a shaping phase for shaping the incident light along the line length direction, in the target light intensity distribution of a word line light beam, the number of light intensity data sampling points along the line length direction is M. samp In the metalens 1, the maximum number of micro-nanostructures 12 arranged along the one-dimensional direction is M nano . M samp =N*M nano , N is greater than or equal to 1; N can be an integer or a decimal.

[0108] Here, the one-dimensional direction refers to any one-dimensional direction on the two-dimensional plane where the metalens 1 is located. Figure 5 FIG. 1 shows a schematic diagram of the arrangement of the micro-nanostructure 12 along a horizontal one-dimensional direction in an embodiment of the present application. Figure 6 FIG. 1 shows a schematic diagram of the micro-nanostructure 12 arranged along an inclined one-dimensional direction in an embodiment of the present application. Figure 5 and Figure 6In one embodiment, the micro-nanostructures 12 on the metalens 1 can be arranged in a horizontal one-dimensional direction or in an inclined one-dimensional direction. When the micro-nanostructures 12 are arranged in a horizontal one-dimensional direction, the metalens 1 can be divided into regions 10a, 10b, 10c, and 10d. When the micro-nanostructures 12 are arranged in an inclined one-dimensional direction, the metalens 1 can be divided into regions 10e, 10f, 10g, and 10h. As can be seen from the figure, there is one micro-nanostructure 12 arranged along the one-dimensional direction in region 10a, three micro-nanostructures 12 arranged along the one-dimensional direction in region 10b, five micro-nanostructures 12 arranged along the one-dimensional direction in region 10c, seven micro-nanostructures 12 arranged along the one-dimensional direction in region 10d, four micro-nanostructures 12 arranged along the one-dimensional direction in region 10e, three micro-nanostructures 12 arranged along the one-dimensional direction in region 10f, four micro-nanostructures 12 arranged along the one-dimensional direction in region 10g, and three micro-nanostructures 12 arranged along the one-dimensional direction in region 10h. After traversing any one-dimensional direction, it can be seen that Figure 5 and Figure 6 In the metalens 1 shown, the maximum number of micro-nanostructures 12 arranged along the one-dimensional direction is 7. Figure 5 as well as Figure 6 In the corresponding embodiment, in the target light intensity distribution of a word line light beam, the number of light intensity data sampling points along the line length direction is at least 7.

[0109] It should be noted that Figure 5 as well as Figure 6 It is only used to exemplarily show the distribution of the micro-nanostructure 12 on the metalens 1. Figure 5 as well as Figure 6 In the figure, the number and arrangement of the micro-nano structures 12 are exemplary and should not limit the scope of protection of this application.

[0110] In this embodiment, since M samp =N*M nano , N is greater than or equal to 1, so in the initial stage of the shaping phase design, on global average, each micro-nanostructure 12 can match at least one unique light intensity data sampling point along the line length; therefore, in the target light intensity distribution of the line light beam, the number of light intensity data sampling points along the line length can effectively meet the requirements of efficient shaping phase design, thereby improving the phase design efficiency of the metalens 1.

[0111] In the embodiment of the present application, the shaping phase can be designed by energy mapping. In the process of designing the shaping phase by energy mapping, it is necessary to integrate the light intensity based on the light intensity data sampled along the line length direction in the target light intensity distribution to determine the local light energy at each position along the line length direction corresponding to a single micro-nano structure 12 on the line light beam. In this case, in order to further improve the phase design efficiency, in one embodiment, M samp =N*M nano Where N is greater than or equal to 4.

[0112] That is, in this embodiment, at the initial stage of the shaping phase design, on global average, each micro-nanostructure 12 can be matched with at least 4 unique light intensity data sampling points along the length of the line; therefore, when the shaping phase is designed by adopting the energy mapping method, the local light energy at each position corresponding to the single micro-nanostructure 12 is obtained by integrating the light intensity based on the light intensity data obtained by at least 4 samples, so that the integration result more accurately reflects the local light energy at each position corresponding to the single micro-nanostructure 12, thereby further improving the phase design efficiency.

[0113] The present application provides a design method for a metalens 1 for projecting a line light spot 2. Figure 7 The flowchart of the design method of the metalens 1 for projecting a line light spot 2 provided by the present application is shown. Figure 7 , the method provided in this application includes:

[0114] Step S110: obtaining an initial target light intensity distribution of the line beam from design requirement information used to describe the performance of the line beam, wherein the line beam is used to project the line beam onto the target plane 3 to obtain the line light spot 2;

[0115] Step S120: reconstructing the initial target light intensity distribution along the line length direction of the line light spot 2 to obtain a reconstructed target light intensity distribution, wherein the resolution of the reconstructed target light intensity distribution along the line length direction is higher than the resolution of the initial target light intensity distribution;

[0116] Step S130: Based on the reconstructed target light intensity distribution and the light intensity distribution of the incident light received by the metalens 1, a shaping phase for shaping the incident light along the line length direction is designed;

[0117] Step S140 : Based on the shaping phase, determine the micro-nanostructures 12 that should be arranged at various positions on the metalens 1 , and design a metalens 1 for projecting a line light spot.

[0118] In the embodiment of the present application, the metalens 1 is used to shape the incident light into a line beam, which is then projected to form a line light spot 2. The design requirement information used to describe the performance of the line beam at least describes the target light intensity distribution of the line beam. Therefore, the target light intensity distribution of the line beam is obtained from the design requirement information. In the embodiment of the present application, the target light intensity distribution obtained from the design requirement information is recorded as the initial target light intensity distribution.

[0119] As previously mentioned, due to the limited pixel resolution of the image, the target light intensity distribution obtained from the design requirements, including the number of intensity data sampling points along the line length, is far from sufficient to efficiently design the shaping phase. In other words, because the resolution of the initial target light intensity distribution is typically low, it is not suitable for direct use in phase design.

[0120] To this end, in an embodiment of the present application, after obtaining the initial target light intensity distribution, the initial target light intensity distribution is reconstructed to obtain a reconstructed target light intensity distribution. The reconstruction process is primarily used to improve the resolution of the target light intensity distribution while maintaining the distribution characteristics of the target light intensity distribution unchanged. In this way, the resolution of the reconstructed target light intensity distribution is higher than the resolution of the initial target light intensity distribution. Specifically, the number of light intensity data sampling points along the line length provided by the reconstructed target light intensity distribution can be N times the maximum number of micro-nanostructures 12 arranged along the one-dimensional direction in the metalens 1, where N is greater than or equal to 1.

[0121] It should be noted that, in general, the light intensity distribution of a line beam along the length of the line is primarily used to achieve various applications such as three-dimensional sensing and positioning identification. There are generally no special requirements for the light intensity distribution along the width of the line. Therefore, the requirements for the shaping accuracy of the light intensity distribution along the width of the line are not high. Therefore, in the embodiments of the present application, the initial target light intensity distribution is reconstructed at least along the length of the line, so that at least along the length of the line, the resolution of the reconstructed target light intensity distribution is higher than the resolution of the initial target light intensity distribution. As for the line width direction, reconstruction is performed selectively depending on the application requirements.

[0122] After obtaining the reconstructed target light intensity distribution, the shaping phase for shaping the incident light along the line length direction is designed in combination with the light intensity distribution of the incident light received by the metalens 1.

[0123] The designed shaping phase is mainly used to modulate the light intensity distribution of the incident light received by the metalens 1 along the line length direction, so that the light intensity distribution of the modulated light beam along the line length direction matches the reconstructed light intensity distribution.

[0124] If the design requirements for a line beam have other performance requirements besides the intensity distribution along its length, other phases can be designed to meet these requirements, and the shaping phase can be superimposed on the other phases to obtain the complete phase ultimately required to be provided by the metalens 1. If the design requirements for a line beam only require the intensity distribution along its length, and the actual beam incident angle at various locations on the metalens 1 is taken into account when designing the shaping phase, then the shaping phase directly constitutes the complete phase ultimately required to be provided by the metalens 1.

[0125] Therefore, based on the shaped phase, the complete phase that the superlens 1 needs to provide in the end is obtained, and then the phase that needs to be provided at each position on the superlens 1 is determined. Then, for each position on the superlens 1, the micro-nanostructure 12 that can provide the corresponding phase is screened out from the micro-nanostructure database, and the screened micro-nanostructure 12 needs to be arranged at the corresponding position; thereby determining the micro-nanostructure 12 that should be arranged at each position on the superlens, and thus designing the superlens 1 required for the target. The designed superlens 1 can shape the incident light into a straight line beam whose light intensity distribution along the length of the line meets the design requirements. Among them, the micro-nanostructure database refers to a database that describes at least the phase provided by micro-nanostructures with various structural parameters for a light beam with a specific central wavelength.

[0126] As can be seen from the above, when the method provided by this application is used to design a metalens 1 for projecting a line of light, the target light intensity distribution directly used to design the phase is the reconstructed target light intensity distribution obtained by reconstructing the initial target light intensity distribution obtained from the design requirement information. Because the resolution of the reconstructed target light intensity distribution is higher than that of the initial target light intensity distribution, the embodiments of this application improve the phase design efficiency of the metalens 1.

[0127] In one embodiment, reconstructing the initial target light intensity distribution along the line length direction of a word line spot to obtain the reconstructed target light intensity distribution includes:

[0128] Extracting discrete light intensity data from the initial target light intensity distribution along the line length direction;

[0129] According to the discrete light intensity data, the light intensity distribution function used to describe the initial target light intensity distribution along the line length is obtained by fitting;

[0130] The light intensity distribution function is discretized and the reconstructed target light intensity distribution is obtained.

[0131] In this embodiment, the initial target light intensity distribution having conventional distribution characteristics along the length of the line is reconstructed by using a fitting function.

[0132] Specifically, an initial target light intensity distribution with regular distribution characteristics along the length of the line refers to an initial target light intensity distribution that varies smoothly or regularly along the length of the line. This type of initial target light intensity can be accurately described by a function along the length of the line. Examples include: an initial target light intensity distribution that is uniform along the length of the line; an initial target light intensity distribution that is symmetrically concave along the length of the line; and an initial target light intensity distribution that is symmetrically convex along the length of the line.

[0133] In this embodiment, after obtaining the initial target light intensity distribution from the design requirement information, the initial target light intensity distribution is sampled at a predetermined step size along the line length, thereby extracting discrete light intensity data from the initial target light intensity distribution. Preferably, the initial target light intensity distribution is sampled at a step size corresponding to the limiting resolution of the initial target light intensity distribution. For example, an image of the initial target light intensity distribution is obtained from the design requirement information; in this case, the step size corresponding to the limiting resolution of the initial target light intensity distribution is a single pixel period. Therefore, the image is sampled pixel by pixel along the line length at a step size of a single pixel period, thereby extracting discrete light intensity data from the initial target light intensity distribution.

[0134] The discrete light intensity data extracted from the initial target light intensity distribution is then fitted to obtain a light intensity distribution function that describes the initial target light intensity distribution along the line length. Depending on the specific general distribution characteristics of the initial target light intensity distribution, the fitted light intensity distribution function can be a linear function, an exponential function, or a polynomial function.

[0135] As can be understood, the light intensity distribution function continuously describes the matching relationship between the coordinates along the length of the line and the light intensity distribution. Therefore, depending on the specific resolution requirements for the target light intensity distribution, the light intensity distribution function is discretized and evaluated at the desired arbitrary resolution. The discrete light intensity data obtained from the discretization of the light intensity distribution function together constitute the reconstructed target light intensity distribution, thereby reconstructing the initial target light intensity distribution.

[0136] In one embodiment, reconstructing the initial target light intensity distribution along the line length direction of a word line spot to obtain the reconstructed target light intensity distribution includes:

[0137] Extracting discrete light intensity data from the initial target light intensity distribution along the line length direction;

[0138] The discrete light intensity data is interpolated to obtain the reconstructed target light intensity distribution.

[0139] In this embodiment, the initial target light intensity distribution having special distribution characteristics along the length of the line is reconstructed by interpolation.

[0140] Specifically, the initial target light intensity distribution with special distribution characteristics along the length of the line refers to the initial target light intensity distribution that changes dramatically or irregularly along the length of the line; this type of initial target light intensity distribution is difficult to accurately describe along the length of the line in the form of a function.

[0141] In this embodiment, after obtaining the initial target light intensity distribution from the design requirement information, the initial target light intensity distribution is sampled at a certain step size along the line length to extract discrete light intensity data from the initial target light intensity distribution. Preferably, the initial target light intensity distribution is sampled at a step size corresponding to the limiting resolution of the initial target light intensity distribution.

[0142] The discrete light intensity data extracted from the initial target light intensity distribution is then interpolated to expand the discrete light intensity data. The expanded discrete light intensity data together constitute the reconstructed target light intensity distribution, thereby reconstructing the initial target light intensity distribution. Specifically, the interpolation process can be performed using Lagrange interpolation, Newton interpolation, spline interpolation, etc.

[0143] In one embodiment, based on the reconstructed target light intensity distribution and the light intensity distribution of the incident light received by the metalens 1, a shaping phase for shaping the incident light along the line length direction is designed, including:

[0144] Based on the law of conservation of energy, the light intensity distribution of the incident light is mapped one-to-one with the reconstructed target light intensity distribution along the length of the line, and the light beam exit angle at each position along the length of the line on the metalens 1 is determined based on the mapping result;

[0145] The shaping phase is calculated based on the light beam exit angle at each position along the length of the metalens 1 and the light beam incident angle at each position along the length of the metalens 1.

[0146] In this embodiment, after obtaining the reconstructed target light intensity distribution, the shaping phase is designed by using energy mapping.

[0147] Specifically, according to the law of conservation of energy, if the energy loss generated by the light beam during propagation is ignored, the total light energy of the incident light received by the metalens is equal to the total light energy of the line light beam modulated by the metalens 1; therefore, the total light energy corresponding to the light intensity distribution of the incident light is equal to the total light energy corresponding to the target light intensity distribution after reconstruction of the line light beam.

[0148] By dividing the light intensity distribution of the incident light along the line length direction, the local light intensity distribution at each position along the line length direction on the metalens 1 can be determined, and then the local light energy received at each position along the line length direction on the metalens 1 can be determined by integration.

[0149] Similarly, by dividing the reconstructed target light intensity distribution along the line length direction, the local light intensity distribution at each position along the line length direction of the line beam can be determined, and then the local light energy at each position along the line length direction of the line beam can be determined by integration.

[0150] Then, based on the principle of energy conservation, each position along the length of the metalens 1 is sequentially mapped to a position along the length of the line beam. The local light energy corresponding to each position on the metalens 1 and the position on the line beam that have a mapping relationship is equal.

[0151] After the mapping is completed, the propagation direction of the light beam at each position along the length of the metalens 1 can be determined based on the mapping result, and then the light beam exit angle at each position along the length of the metalens 1 can be determined.

[0152] At the same time, if the light source is known and the relative position and distance between the light source and the metalens 1 are determined, the incident angle of the light beam at each position along the line length of the metalens 1 can naturally be determined. Alternatively, if the incident angle of the light beam at each position along the line length of the metalens 1 is difficult to determine with sufficient accuracy, a collimation phase can be designed in addition to the shaping phase to collimate the incident light along the line length. Under the influence of the collimation phase corresponding to the line length, the incident angle of the light beam at each position along the line length of the metalens can be considered to be zero for the shaping phase.

[0153] Therefore, by combining the light beam exit angle at each position along the line length of the metalens 1 and the light beam incident angle at each position along the line length of the metalens 1, and applying the generalized Snell's law, the shaping phase used to shape the incident light along the line length can be calculated.

[0154] In one embodiment, based on the reconstructed target light intensity distribution and the light intensity distribution of the incident light received by the metalens 1, a shaping phase for shaping the incident light along the line length direction is designed, including:

[0155] Along the line length, the reconstructed target light intensity distribution is constructed as a target image used as the target output of the phase retrieval algorithm;

[0156] Based on the intensity distribution of the incident light along the length direction and the target image, the phase recovery algorithm is applied to obtain the shaped phase.

[0157] In this embodiment, after obtaining the reconstructed target light intensity distribution, a phase recovery algorithm is used to design the shaping phase along the line length direction.

[0158] Specifically, a phase retrieval algorithm uses the diffraction theory of light to calculate the diffraction of the input light field and obtain the intensity distribution of the output light field. The calculated output light field intensity distribution is then compared with the target output light field intensity distribution. Based on the comparison results, the algorithm iteratively determines the phase that ensures the calculated output light field intensity distribution sufficiently matches the target output light field intensity distribution. Common phase retrieval algorithms include the GS (Gerchberg-Saxton) algorithm and the YG (Yang-Gu) algorithm.

[0159] In this embodiment, after obtaining the reconstructed target light intensity distribution, the reconstructed target light intensity distribution is constructed as a target image along the line length. The light intensity distribution of the incident light along the line length is then used as the input of a phase recovery algorithm, and the target image is used as the target output of the phase recovery algorithm. Under the action of the phase recovery algorithm, the phase used to modulate the light intensity distribution of the incident light along the line length to the reconstructed target light intensity distribution along the line length is obtained. In other words, the shaping phase used to shape the incident light along the line length is obtained.

[0160] In one embodiment, the method provided by the present application further includes:

[0161] Based on the distance between the metalens 1 and the light source, a collimation phase is designed to collimate the incident light along the line length direction; the designed phase of the metalens 1 includes a shaping phase and a collimation phase corresponding to the line length direction.

[0162] In this embodiment, in order to make the line light beam shaped by the metalens 1 have a higher edge steepness in the line length direction, thereby improving the light energy utilization rate of the line light beam, in addition to designing a shaping phase for shaping the incident light along the line length direction, a collimation phase for collimating the incident light along the line length direction is also designed.

[0163] In this way, the complete phase that the designed metalens 1 is ultimately required to provide includes the shaping phase and the collimation phase corresponding to the line length direction.

[0164] In this embodiment, the collimation phase corresponding to the line length direction is mainly designed according to the distance between the super lens 1 and the light source.

[0165] Specifically, in this embodiment, the collimation phase corresponding to the line length direction can be calculated using any of the following formulas:

[0166]

[0167] in, is the collimation phase corresponding to the line length direction; λ is the central wavelength of the incident light; x1 is the projection length of the distance between each position on the metalens 1 and the center position of the metalens 1 in the line length direction; d1 is the distance between the metalens 1 and the light source.

[0168] In another embodiment, the collimation phase corresponding to the line length direction is calculated using the binary surface phase formula shown below:

[0169]

[0170] in, is the collimation phase corresponding to the line length direction; A i are the binary surface coefficients to be optimized; N is the number of binary surface coefficients. Based on the optimized binary surface coefficients, the corresponding collimation phase corresponding to the line length direction is obtained. Then, the simulation software is used to simulate the result of the incident light continuing to diffract and propagate after being modulated by the collimation phase corresponding to the line length direction, thereby verifying the actual collimation effect of the collimation phase corresponding to the line length direction. If the actual collimation effect of the collimation phase corresponding to the line length direction does not meet expectations, the binary surface coefficients are optimized again and the simulation verification is repeated until the actual collimation effect of the collimation phase corresponding to the line length direction meets expectations.

[0171] In one embodiment, the method provided by the present application further includes:

[0172] Obtain the target line width of the line spot 2 from the design requirement information;

[0173] Based on the target line width and the intensity distribution of the incident light, a line width compression phase is designed to compress the line width of the line spot 2 along the line width direction; the designed phase of the metalens 1 includes a shaping phase and a line width compression phase.

[0174] The narrower the line width of the line spot 2, the more concentrated its light energy is, which is more conducive to three-dimensional sensing or positioning identification. Therefore, in this embodiment, if there are specific requirements for the performance of the metalens 1 in terms of the line width of the line spot 2, in addition to the shaping phase designed to shape the incident light along the line length direction, a line width compression phase is also designed to compress the line width of the line spot 2 along the line width direction.

[0175] Specifically, the target line width of the line spot 2 is obtained from the design requirement information. The target line width of the line spot 2 generally describes the upper limit of the line width of the line spot 2 at a specific working distance; the working distance refers to the distance between the metalens 1 and the target plane 3 used to project the line spot 2.

[0176] After determining the target line width of the line spot 2, a line width compression phase is designed based on the target line width and the intensity distribution of the incident light. Under the effect of the line width compression phase, the line width of the line spot 2 can meet the target line width requirement.

[0177] In this way, the phase that the designed metalens 1 ultimately needs to provide includes a shaping phase and a linewidth compression phase.

[0178] In one embodiment, the linewidth compression phase is a collimation phase along the linewidth direction, or a focusing phase along the linewidth direction.

[0179] Specifically, in this embodiment, the linewidth compression phase can be calculated using any formula shown below:

[0180]

[0181] in, is the line width compression phase; λ is the central wavelength of the incident light; y1 is the projection length of the distance between each position on the superlens 1 and the center position of the superlens 1 in the line width direction; f1 is the focal length of the superlens 1.

[0182] When the linewidth compression phase is a collimating phase along the linewidth direction, f1 is equal to the distance between the superlens 1 and the light source; when the linewidth compression phase is a focusing phase along the linewidth direction, f1 is less than the distance between the superlens 1 and the light source.

[0183] Compared with the collimating phase along the line width direction, the focusing phase along the line width direction has a stronger ability to compress the line width; that is, compared with the narrowest line width that can be compressed by the collimating phase along the line width direction, the narrowest line width that can be compressed by the focusing phase along the line width direction is smaller.

[0184] However, compared to the narrowest linewidth-adaptive working distance range that can be compressed by the collimation phase along the linewidth direction, the narrowest linewidth-adaptive working distance range that can be compressed by the focus phase along the linewidth direction is also smaller. Therefore, compared to the collimation phase along the linewidth direction, the focus phase along the linewidth direction has stricter working distance requirements and is slightly less applicable.

[0185] Therefore, whether to use the collimation phase along the line width direction as the line width compression phase or to use the focusing phase along the line width direction as the line width compression phase requires comprehensive consideration of the requirements for the narrowest line width and the requirements for the working distance.

[0186] In another embodiment, the linewidth compression phase is calculated using the binary phase formula shown below:

[0187]

[0188] in, is the linewidth compression phase; A i are the binary surface coefficients to be optimized; N is the number of binary surface coefficients. Based on the optimized binary surface coefficients, the corresponding linewidth compression phase is obtained. Then, the simulation software is used to simulate the diffraction and propagation of incident light after the linewidth compression phase modulation, thereby verifying the actual linewidth compression effect of the linewidth compression phase. If the actual linewidth compression effect of the linewidth compression phase does not meet expectations, the binary surface coefficients are optimized again and the simulation verification is repeated until the actual linewidth compression effect of the linewidth compression phase meets expectations.

[0189] The present application also provides an emission system for projecting a line light spot 2 . Figure 8 The schematic diagram of the structure of the emission system for projecting a line of light spots provided by the present application is shown. Figure 8 The line light beam emission system provided in this application includes: a light source 5; a super lens 1.

[0190] The metalens 1 is disposed on the light-emitting side of the light source 5. Thus, after the light beam emitted by the light source 5 propagates to the metalens 1, it is modulated into a line beam by the metalens 1. After exiting the metalens 1, the line beam continues to propagate until it reaches the target plane 3, where it projects a line spot 2 onto the target plane 3. The x-axis represents the length of the line spot 2, the y-axis represents the width of the line spot 2, and the z-axis represents the direction perpendicular to the metalens 1.

[0191] Refer to the description of any of the above embodiments, and the detailed structural details of the metalens 1 will not be repeated here.

[0192] Example 1

[0193] In the line beam emission system of Example 1, the light source is an edge-emitting laser (EEL). The central wavelength of the light beam emitted by the light source is 650 nm, the full divergence angle along the line length is 11.2°, the full divergence angle along the line width is 28.9°, and the effective light-emitting area along the line length is 180 μm.

[0194] For the target linear beam requirement, it is required to generate a linear light spot with a line width less than 2mm within the working distance range of 200mm to 2000mm; the light intensity distribution of the generated linear light spot along the length of the line is symmetrical and concave, the peak-to-valley ratio of the light intensity along the length of the line is 1:0.76, and the divergence angle between the two peaks of the light intensity in the length direction is 150°.

[0195] Figure 9 The diagram shows a line light spot projected by a line light beam emitted by the line light beam emitting system of Example 1. Figure 10 Shown Figure 9 The light intensity distribution curve of the line light spot in the line width direction is shown. Figure 11 Shown Figure 9 The light intensity distribution curve of the line light spot in the line length direction is shown.

[0196] At a working distance of 1500mm, the projection is Figure 9 The line spot shown in the figure. Figure 10 It can be seen that the peak light intensity As the line width boundary, the line width of the single-line spot is 1.8mm, which meets the line width requirement of less than 2mm. Figure 11 It can be seen that along the length of the line, the light spot has a light intensity peak-to-valley ratio of 1:0.76 within the divergence angle range of -75° to 75°, which meets the requirements of the peak-to-valley ratio and divergence angle.

[0197] Example 2

[0198] In the linear beam emission system of Example 2, the light source is an EEL. The central wavelength of the light beam emitted by the light source is 450nm, the full divergence angle along the line length is 7.1°, and the full divergence angle along the line width is 31.5°. The effective light emitting area consists of 15 light sources, each with 5 light sources arranged in three rows, parallel to the line length. Each light source has a dimension of 320μm along the line length, a spacing of 150μm along the line length, and a spacing of 15μm along the line width.

[0199] The target straight-line beam is required to generate a straight-line spot with a line width of less than 1.9mm within a working distance range of 400mm to 1000mm. The generated straight-line spot has a uniform but eccentric light intensity distribution along the length of the line, with a divergence angle range of -15° to 75° in the uniform area. The criterion for judging uniformity is: if the light intensity non-uniformity is less than 8%, it indicates that the light intensity is uniform.

[0200] Figure 12 The diagram shows a line light spot projected by a line light beam emitted by the line light beam emitting system of Example 2. Figure 13 Shown Figure 12 The light intensity distribution curve of the line light spot in the line width direction is shown. Figure 14 Shown Figure 12 The light intensity distribution curve of the line light spot in the line length direction is shown.

[0201] At a working distance of 1000mm, the projection is Figure 12 The line spot shown in the figure. Figure 13 It can be seen that the peak light intensity As the line width boundary, the line width of the single-line spot is 1.87mm, which meets the line width requirement of less than 1.9mm. Figure 14 It can be seen that along the length of the line, the light intensity non-uniformity of the line light spot is 3.9% within the divergence angle range of -15° to 75°, meeting the requirements of uniformity, eccentricity and divergence angle.

[0202] Example 3

[0203] In the linear light beam emission system of Example 3, the light source is an EEL. The light beam emitted by the light source has a central wavelength of 950 nm, a full divergence angle of 8.6° along the line length, a full divergence angle of 36.1° along the line width, and an effective light emitting area of ​​60 μm along the line length.

[0204] The target linear beam is required to generate a linear spot with a line width of less than 0.8mm within a working distance range of 100mm to 300mm. The generated linear spot has a uniform light intensity distribution along the length of the line, with a divergence angle of 90° in the uniform area. The criterion for judging uniformity is: if the light intensity non-uniformity is less than 3%, it indicates that the light intensity is uniform.

[0205] Figure 15 The diagram shows a line light spot projected by a line light beam emitted by the line light beam emitting system of Example 3. Figure 16 Shown Figure 12 The light intensity distribution curve of the line light spot in the line width direction is shown. Figure 17 Shown Figure 12 The light intensity distribution curve of the line light spot in the line length direction is shown.

[0206] At a working distance of 200mm, the projection is Figure 15 The line spot shown in the figure. Figure 16 It can be seen that the peak light intensity As the line width boundary, the line width of the single-line spot is 0.59mm, which meets the line width requirement of less than 0.8mm. Figure 17 It can be seen that along the length of the line, the light intensity non-uniformity of the line light spot is 1.52% within the divergence angle range of -45° to 45°, meeting the requirements of uniformity and divergence angle.

[0207] Example 4

[0208] In the linear beam emission system of Example 4, the light source is a VCSEL (Vertical-Cavity Surface-Emitting Laser). The central wavelength of the light beam emitted by the light source is 940nm, the full divergence angle is 29°, and the effective light-emitting area is 20μm*280μm. The effective light-emitting area is composed of eight light sources arranged along the length of the line.

[0209] Figure 18The light intensity distribution of the line beam of Example 4 along the length of the line is shown. For the target line beam, it is required to generate a line spot with a line width less than 2.5mm at a working distance of 400mm; the generated line spot should meet the following requirements along the length of the line: Figure 15 The special light intensity distribution shown.

[0210] Figure 19 The diagram shows a line light spot projected by a line light beam emitted by the line light beam emitting system of Example 4. Figure 20 Shown Figure 19 The light intensity distribution curve of the line light spot in the line width direction is shown. Figure 21 Shown Figure 19 The light intensity distribution curve of the line light spot in the line length direction is shown.

[0211] At a working distance of 400mm, the projection is Figure 19 The line spot shown in the figure. Figure 20 It can be seen that the peak light intensity As the line width boundary, the line width of the single-line spot is 2.1mm, which meets the line width requirement of less than 2.5mm. Figure 21 It can be seen that along the length of the line, the light intensity distribution of the line spot satisfies Figure 15 Special needs as indicated.

[0212] The present application also provides a design device for a metalens for projecting a line of light spots. Figure 22 Schematic diagram of the design device of the metalens provided by this application. Figure 22 , the design device of the metalens provided in this application includes:

[0213] An initial target light intensity distribution acquisition module 610 is configured to acquire an initial target light intensity distribution of a line-line light beam from design requirement information describing the performance of a line-line light beam, wherein the line-line light beam is used to project a line-line light spot on a target plane;

[0214] The light intensity distribution reconstruction module 620 is configured to reconstruct the initial target light intensity distribution along the line length direction of the line light spot to obtain a reconstructed target light intensity distribution, wherein the resolution of the reconstructed target light intensity distribution along the line length direction is higher than the resolution of the initial target light intensity distribution;

[0215] A shaping phase design module 630 is configured to design a shaping phase for shaping the incident light along the line length direction based on the reconstructed target light intensity distribution and the light intensity distribution of the incident light received by the metalens;

[0216] The micro-nano structure determination module 640 is configured to determine the micro-nano structures that should be arranged at various positions on the metalens based on the shaping phase, and design a metalens for projecting a line light spot.

[0217] In an exemplary embodiment of the present application, the light intensity distribution reconstruction module 620 is configured as follows:

[0218] Extracting discrete light intensity data from the initial target light intensity distribution along the line length direction;

[0219] According to the discrete light intensity data, the light intensity distribution function used to describe the initial target light intensity distribution along the line length is obtained by fitting;

[0220] The light intensity distribution function is discretized and the reconstructed target light intensity distribution is obtained.

[0221] In an exemplary embodiment of the present application, the light intensity distribution reconstruction module 620 is configured as follows:

[0222] Extracting discrete light intensity data from the initial target light intensity distribution along the line length direction;

[0223] The discrete light intensity data is interpolated to obtain the reconstructed target light intensity distribution.

[0224] In an exemplary embodiment of the present application, the shaping phase design module 630 is configured as follows:

[0225] Based on the law of conservation of energy, the intensity distribution of the incident light is mapped one-to-one with the reconstructed target intensity distribution along the length of the line, and the light beam exit angle at each position along the length of the line on the metalens is determined based on the mapping result;

[0226] The shaping phase is calculated based on the light beam exit angle at each position along the length of the metalens and the light beam incident angle at each position along the length of the metalens.

[0227] In an exemplary embodiment of the present application, the shaping phase design module 630 is configured as follows:

[0228] Along the line length, the reconstructed target light intensity distribution is constructed as a target image used as the target output of the phase retrieval algorithm;

[0229] Based on the intensity distribution of the incident light along the length direction and the target image, the phase recovery algorithm is applied to obtain the shaped phase.

[0230] In an exemplary embodiment of the present application, the design device is configured as follows:

[0231] Based on the distance between the metalens and the light source, a collimation phase is designed to collimate the incident light along the line length direction; the phase of the designed metalens includes a shaping phase and a collimation phase corresponding to the line length direction.

[0232] In an exemplary embodiment of the present application, the design device is configured as follows:

[0233] Obtain the target line width of the line spot from the design requirement information;

[0234] Based on the target line width and the intensity distribution of the incident light, a line width compression phase is designed to compress the line width of the single-line light spot along the line width direction; the phase of the designed metalens includes a shaping phase and a line width compression phase.

[0235] In an exemplary embodiment of the present application, the linewidth compression phase is a collimation phase along the linewidth direction, or a focusing phase along the linewidth direction.

[0236] The present application also provides an electronic device. The electronic device is in the form of a general-purpose computing device. The components of the electronic device may include but are not limited to: at least one processor, at least one memory, and a bus connecting different system components (including memory and processor). The processor may include the following: Figure 22 The various modules in the device shown.

[0237] The memory stores program codes that can be executed by the processor so that the processor performs the steps of the exemplary embodiments described in the various exemplary embodiments above. For example, the processor can execute the following steps: Figure 7 The steps shown in .

[0238] The memory may include readable media in the form of volatile memory, such as random access memory (RAM) and / or cache memory, and may further include read-only memory (ROM).

[0239] The memory may also include a program / utility having a set (at least one) of program modules, such program modules including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0240] The bus may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, or a local bus using any of a variety of bus architectures.

[0241] The present application also provides a computer-readable storage medium having computer-readable instructions stored thereon. When the computer-readable instructions are executed by a processor of a computer, the computer is caused to execute the method provided by any of the above method embodiments.

[0242] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the utility model disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered merely as exemplary, and the true scope and spirit of the present application are indicated by the appended claims.

Claims

1. A metalens for projecting a line of light, characterized in that: The metalens includes a substrate and a micro-nano structure provided on the substrate; the metalens is used to shape the incident light into a line beam, and the line beam is used to project the line light spot onto a target plane; The divergence angle of the incident light parallel to the line length direction of the word line light spot is less than or equal to the divergence angle of the incident light parallel to the line width direction of the word line light spot.

2. The metalens according to claim 1, wherein The active area of ​​the metalens includes at least one first arched area and at least one second arched area; The top of the first arched area faces the second arched area, and the top of the second arched area faces the first arched area.

3. The metalens according to claim 2, wherein The first arched area and the second arched area are symmetrically distributed with respect to a target direction in a two-dimensional plane where the metalens is located, so that a line connecting a center of the line light spot and a center of the effective area is perpendicular to the metalens; The target direction is perpendicular to the dome orientation of the dome region.

4. The metalens according to claim 2, wherein The first arched area and the second arched area are asymmetrically distributed with respect to a target direction in a two-dimensional plane where the metalens is located, so that a line connecting a center of the line light spot and a center of the effective area is inclined with respect to the metalens; The target direction is perpendicular to the dome orientation of the dome region.

5. The metalens according to claim 2, wherein When the effective area includes at least two first areas, the tops of the first arched areas are oriented in the same direction, and the first arched areas are adjacent to each other in a concentric manner. When the effective area includes at least two second areas, the tops of the second arched areas face the same direction, and the second arched areas are adjacent to each other in a concentric manner.

6. The metalens according to claim 1, wherein When a shaping phase is designed for shaping the incident light along the line length direction of the line light spot, in the target light intensity distribution of the line light beam, the number of light intensity data sampling points along the line length direction is N times the maximum number of micro-nano structures arranged along the one-dimensional direction in the metalens, where N is greater than or equal to 1.

7. The metalens according to claim 6, wherein N is greater than or equal to 4.

8. An emission system for projecting a line of light spots, characterized in that: The emission system comprises: a light source; a super lens according to any one of claims 1 to 7; The super lens is arranged on the light-emitting side of the light source.

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