Metasurface lens imaging apparatus and method

Abstract

The application provides a metasurface lens imaging device and method. The metasurface lens imaging device comprises: an imaging sensor comprising three imaging areas located at different positions in the cross section of the optical axis; a metasurface lens arranged in the object side direction of the imaging sensor along the optical axis and comprising three phase compensation parts located at different positions in the cross section of the optical axis, the three phase compensation parts compensating the phase of incident light differently from each other, so that the incident light forms images in the three imaging areas respectively, and the three images formed correspond one-to-one to the three phase compensation parts; and a synthesizer for synthesizing the three images.

Description

Technical Field

[0001] The present application relates to the field of optical equipment, and more specifically, to a metasurface lens imaging device and method, as well as a method for forming a metasurface lens imaging device. Background Art

[0002] In the field of imaging, lenses are used to achieve imaging or projection. Traditional lenses are made of transparent materials such as resin, plastic, and glass. These lenses introduce optical path differences through a gradual thickness variation, causing light to focus or diverge. This thickness gradient generally requires a large radial dimension.

[0003] In March 2015, Capasso et al. published a paper on metasurfaces in Science, Volume 347, Issue 6228. This paper sparked worldwide research on metasurface lenses. Metasurface lenses differ from traditional lenses in that they utilize micro- and nanoscale structures. This structure can introduce a shape-dependent Pancharatnam–Berry phase difference into the incident light, thereby arbitrarily modulating the phase of the scattered incident light. Therefore, the Pancharatnam–Berry phase difference can replace the optical path difference of traditional lenses in light modulation.

[0004] Metasurface lenses can form substantially flat optical devices that are easier to integrate, and their size can be significantly reduced compared to traditional lenses. However, because metasurface lenses rely on diffraction optics rather than geometric optics, they can avoid inherent aberrations of traditional lenses, such as spherical aberration, while also generating new types of aberrations specific to diffraction optics, particularly chromatic aberration.

[0005] Although various complex phase compensation parts are used in the prior art to compensate for the chromatic aberration of the metasurface lens, these phase compensation parts may be significantly different at each position of the lens, which greatly increases the manufacturing complexity and corresponding costs. Summary of the Invention

[0006] An embodiment of the present application provides a metasurface lens imaging device, which includes: an imaging sensor, including three imaging areas located at different positions in the cross-section of an optical axis; a metasurface lens, arranged along the optical axis in the object-side direction of the imaging sensor, and including three phase compensation parts located at different positions in the cross-section of the optical axis, the three phase compensation parts performing different phase compensations on the incident light, so that the incident light forms images in the three imaging areas, respectively, and the three images formed correspond one-to-one to the three phase compensation parts; and a synthesizer for synthesizing the three images.

[0007] In one embodiment, the metasurface lens imaging device further includes: an aperture, which is arranged along the optical axis in the object side direction of the metasurface lens.

[0008] In one embodiment, the operating wavelengths of the three phase compensators are different from each other.

[0009] In one embodiment, the three phase compensators include: a first phase compensator operating at a red wavelength; a second phase compensator operating at a green wavelength; and a third phase compensator operating at a blue wavelength.

[0010] In one embodiment, the operating wavelength of the first phase compensator is within 680.0 nm to 720.0 nm, the operating wavelength of the second phase compensator is within 526.0 nm to 566.0 nm, and the operating wavelength of the third phase compensator is within 515 nm to 555.0 nm.

[0011] In one embodiment, the operating wavelength of the first phase compensating portion is 700.0 nm, the operating wavelength of the second phase compensating portion is 546.1 nm, and the operating wavelength of the third phase compensating portion is 534.8 nm.

[0012] In one embodiment, the metasurface lens imaging device further includes three filters, which are arranged in a one-to-one correspondence with the three phase compensation parts in the object side direction of the phase compensation part.

[0013] In one embodiment, the phase compensation unit includes a nanoantenna array formed by multiple nanoantennas; the nanoantenna has a long axis and a short axis that are perpendicular to each other in the cross section of the optical axis, and the direction of the long axis of the nanoantenna is set based on the position of the nanoantenna in the nanoantenna array.

[0014] In one embodiment, the nanoantenna array has a center; and a rotation angle is provided between the long axes of two radially adjacent nanoantennas in each nanoantenna array, where the rotation angle is determined based on the distances of the two nanoantennas relative to the center.

[0015] In one embodiment, among the rotation angles of the nanoantenna at corresponding positions in the three phase compensators, the one corresponding to the phase compensator with the smallest working wavelength is the largest, and the one corresponding to the phase compensator with the largest working wavelength is the smallest.

[0016] In one embodiment, the imaging sensor is a grayscale sensor.

[0017] In one embodiment, the metasurface lens includes a first sub-lens, a second sub-lens, and a third sub-lens; the first sub-lens includes a first phase compensation portion, the second sub-lens includes a second phase compensation portion, and the third sub-lens includes a third phase compensation portion.

[0018] In one embodiment, the phase compensator comprises an inorganic dielectric material or a transparent organic material.

[0019] Exemplarily, the material of the phase compensating portion is an inorganic dielectric material or a transparent organic material.

[0020] In one embodiment, the material of the phase compensator includes at least one of zinc sulfide, magnesium fluoride, titanium dioxide, zirconium oxide, silicon hydride, crystalline silicon, silicon nitride, amorphous silicon, gallium nitride, gallium phosphide, or gallium arsenide.

[0021] Exemplarily, the material of the phase compensation part is one of zinc sulfide, magnesium fluoride, titanium dioxide, zirconium oxide, silicon hydride, crystalline silicon, silicon nitride, amorphous silicon, gallium nitride, gallium phosphide or gallium arsenide.

[0022] In one embodiment, the material of the phase compensator includes polymethyl methacrylate. Exemplarily, the material of the phase compensator is polymethyl methacrylate.

[0023] Another aspect of the present application provides a metasurface lens imaging method, comprising: utilizing three phase compensation portions to cause incident light to form images in three imaging areas, respectively, and the three images formed correspond one-to-one to the three phase compensation portions, wherein the three phase compensation portions are arranged along the optical axis in the object side direction of the three imaging areas and are located at different positions in the cross section of the optical axis, the three phase compensation portions perform different phase compensations on the incident light, and the three imaging areas are located at different positions in the cross section of the optical axis; and synthesizing the three images.

[0024] In one embodiment, the operating wavelengths of the three phase compensation parts are red light wavelength, green light wavelength and blue light wavelength respectively.

[0025] In one embodiment, the operating wavelengths of the three phase compensators are respectively within 680.0 nm to 720.0 nm, within 526.0 nm to 566.0 nm, and within 515 nm to 555.0 nm.

[0026] In one embodiment, the operating wavelengths of the three phase compensation parts are 700.0 nm, 546.1 nm, and 534.8 nm, respectively.

[0027] In one embodiment, the method further includes: filtering the three parts of light corresponding to the three phase compensation parts in the incident light respectively.

[0028] Another aspect of the present application provides a method for forming a metasurface lens imaging device, comprising: forming an imaging sensor to have three imaging regions located at different positions in a cross section of an optical axis; disposing a metasurface lens along the optical axis in an object-side direction of the imaging sensor, wherein the metasurface lens includes three phase compensating portions located at different positions in the cross section of the optical axis, the three phase compensating portions performing different phase compensations on incident light, so that the incident light forms images in the three imaging regions, respectively, and the three formed images correspond one-to-one to the three phase compensating portions; and

[0029] The synthesizer is communicatively connected to the imaging sensor, wherein the synthesizer is used to synthesize three images.

[0030] In one embodiment, the three phase compensating parts include: a first phase compensating part, whose operating wavelength is a red light wavelength; a second phase compensating part, whose operating wavelength is a green light wavelength; and a third phase compensating part, whose operating wavelength is a blue light wavelength; the metasurface lens includes a first sub-lens, a second sub-lens and a third sub-lens; wherein the method further includes: respectively arranging the first phase compensating part, the second phase compensating part and the third phase compensating part on the first sub-lens, the second sub-lens and the third sub-lens.

[0031] The metasurface lens imaging device provided in the embodiments of the present application has a relatively low manufacturing difficulty for each component structure, making the device easy to manufacture and low in cost. The image chromatic aberration in each imaging region is relatively low, and by synthesizing the images, an image with relatively low chromatic aberration and high imaging quality can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0033] Figure 1 1 shows a schematic structural diagram of a metasurface lens imaging device according to an embodiment of the present application;

[0034] Figure 2 Shown Figure 1 A schematic diagram of an imaging area of ​​an imaging sensor;

[0035] Figure 3 Shown Figure 1 Left-side schematic diagram of the supersurface lens;

[0036] Figure 4 Shown Figure 3 Enlarged view of point A in the middle;

[0037] Figure 5 shows a phase compensation curve that the phase compensation portion should have at an exemplary operating wavelength;

[0038] Figure 6 1 shows a schematic diagram of a metasurface lens according to another embodiment of the present application;

[0039] Figure 7 1 shows a schematic diagram of a metasurface lens according to another embodiment of the present application;

[0040] Figure 8 1 shows a schematic diagram of a metasurface lens according to another embodiment of the present application;

[0041] Figure 9 A metasurface lens imaging method according to an embodiment of the present application is shown; and

[0042] Figure 10 A method for forming a metasurface lens imaging device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0043] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of exemplary embodiments of the present application and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0044] It should be noted that in this specification, terms such as first, second, and third are used solely to distinguish one feature from another and do not limit the features in any way. Therefore, without departing from the teachings of this application, the first phase compensator discussed below could also be referred to as the second phase compensator, and vice versa.

[0045] In the accompanying drawings, the thickness, size, and shape of components have been slightly adjusted for ease of illustration. The drawings are for illustration purposes only and are not drawn strictly to scale. For example, the height and length dimensions of the nanoantennas are not in scale as would be used in actual production. As used herein, the terms "substantially," "approximately," and similar terms are intended to indicate approximations, not degrees, and are intended to account for inherent variations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art.

[0046] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application." And, the term "exemplary" is intended to refer to an example or illustration.

[0047] Unless otherwise defined, all words used herein (including engineering terms and scientific and technological terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that, unless otherwise specified in this application, words defined in commonly used dictionaries should be interpreted as having the same meaning as they do in the context of the relevant technology, and should not be interpreted in an idealized or overly formal sense.

[0048] It should be noted that, unless otherwise specified or inconsistent with the context, the embodiments and features of the embodiments in this application may be combined with each other. Furthermore, unless expressly limited or inconsistent with the context, the specific steps included in the methods described in this application are not necessarily limited to the order in which they are described, but may be performed in any order or in parallel. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0049] refer to Figure 1 The metasurface lens imaging device provided by the embodiment of the present application includes: an imaging sensor 100, a metasurface lens 200 and a synthesizer (not shown). The metasurface lens 200 and the imaging sensor 100 are generally arranged along the optical axis Z, wherein Figure 1 The left side shown is the object side of the optical axis Z, and the right side is the image side of the optical axis Z. The combiner and the imaging sensor 100 are typically in communication connection.

[0050] The imaging sensor 100 has an imaging surface facing the object side. Generally speaking, pixel sensors that convert light signals into electrical signals are arranged in the imaging surface of the imaging sensor 100. The imaging surface of the imaging sensor 100 can receive all imaging light and form an overall image. Specifically, this image can be reflected by image data, such as image data based on pixel points. Exemplarily, the imaging surface of the imaging sensor 100 can be divided into multiple imaging areas, or the imaging surface is composed of multiple imaging areas located at different positions in the cross section of the optical axis Z. Reference Figure 2 The imaging surface may include a first imaging area 110 , a second imaging area 120 and a third imaging area 130 .

[0051] The metasurface lens 200 is disposed on the object side of the imaging sensor 100. Figure 3 In the cross section of the optical axis Z, the metasurface lens 200 includes multiple phase compensating sections, for example, a first phase compensating section 210, a second phase compensating section 220, and a third phase compensating section 230. The phase compensating section may include a substrate and a nanoantenna array disposed on the substrate, and the substrate may be configured to be transparent. Among the multiple phase compensating sections included in the metasurface lens 200, at least two have different phase compensations for light. Exemplarily, the first phase compensating section 210, the second phase compensating section 220, and the third phase compensating section 230 have different phase compensations for light.

[0052] refer to Figure 2 and Figure 3 , Figure 2 and Figure 3 The figures show projections from the object side to the image side of the optical axis Z. It can be seen that each phase compensator corresponds to an imaging area. The first phase compensator 210 is located on the upper side of the diagram and is fan-shaped, corresponding to the first imaging area 110. The second phase compensator 220 is located on the lower left side of the diagram and is also fan-shaped, corresponding to the second imaging area 120. The third phase compensator 230 is located on the lower right side of the diagram and is also fan-shaped, corresponding to the third imaging area 130. The three fan-shaped phase compensators can effectively receive all incident light and make better use of the imaging surface.

[0053] The metasurface lens device provided by the present application sets the metasurface lens 200 at a preset position on the object side of the imaging sensor 100. For example, the distance between the two is the focal length f of the metasurface lens 200. Since the metasurface lens 200 relies on diffraction optics rather than geometric optics in principle, after the incident light L1 incident from the object side of the metasurface lens 200 is irradiated on the metasurface lens 200, the diffracted light L2 emitted by the image side of the metasurface lens 200 cannot be simply equivalent to a light beam in geometric optics. Each point at the metasurface lens 200 is equivalent to a secondary wave source, and each wave source emits a light wave based on a certain initial phase, and the light waves diffused from different wave sources interfere with each other.

[0054] Therefore, on the metasurface lens 200, the wave source 201 corresponding to the optical axis Z and the wave source 202 away from the optical axis Z usually have an optical path difference at the same point in the image side space (for example, on the optical axis Z). If the initial phases of the two are the same, they may interfere destructively at this point. In the present application, the light wave at the wave source 202 is introduced into a Pancharatnam–Berry (PB) phase difference related to the shape of the phase compensation portion by the phase compensation portion. The phase difference can offset the optical path difference, thereby causing the light wave emitted from the wave source 201 and the light wave at the wave source 202 to interfere constructively at a preset position rather than destructively. Specifically, the interference is constructive at the imaging surface of the imaging sensor 100. It can then be considered that the focus of the metasurface lens 200 is located at the imaging surface, for example, the focal length f is 50μm.

[0055] The diffracted light L2 emitted by the metasurface lens 200 is imaged on the imaging sensor 100. The three phase compensation parts compensate the incident light L1 differently and correspond to the three imaging areas one by one, so that the incident light L1 forms images in the three imaging areas respectively. Figure 2 , the light emitted from the first phase compensating portion 210 can form a first image 111 in the first imaging area 110. The light emitted from the second phase compensating portion 220 can form a second image 121 in the second imaging area 120, and the light emitted from the third phase compensating portion 230 can form a third image 131 in the third imaging area 130. Since each phase compensating portion performs different phase compensation on the light, the three images are also different. It can be understood that the image of the incident light L1 on the imaging sensor 100 after passing through the metasurface lens 200 may also include images other than the aforementioned three images.

[0056] The synthesizer is used to directly obtain data corresponding to the first image 111, the second image 121 and the third image 131 from the imaging sensor 100, or to extract these three images from the imaging data of the imaging sensor 100, and then synthesize the image to be output based on these three images.

[0057] The metasurface lens imaging device provided in the present embodiment employs three phase compensation units to form separate images, reducing the number of factors to consider for each phase compensation unit. This simplifies the structure and reduces manufacturing difficulty and cost. Furthermore, the output image synthesized from the three images can effectively overcome chromatic aberration.

[0058] In an exemplary embodiment, the metasurface lens imaging device further includes an aperture 300 disposed on the object side of the metasurface lens 200 along the optical axis Z. The aperture 300 is configured to limit an incident light beam and thereby transmit the incident light L1 to the metasurface lens 200 .

[0059] In an exemplary embodiment, the operating wavelength of any of the three phase compensators is different from the operating wavelengths of the others. The operating wavelength of a phase compensator is the wavelength of light whose phase is compensated by that phase compensator. Setting the three phase compensators to different operating wavelengths can result in different color shifts in the image produced by imaging sensor 100. For example, the operating wavelengths of the three phase compensators can correspond to the three wavelengths in an RGB color mode. The three images thus generated can be effectively combined into a color image.

[0060] Furthermore, when the biased colors of the first image 111, the second image 121, and the third image 131 are different, the pixel receptors in the first imaging area 110, the second imaging area 120, and the third imaging area 130 do not need to have three sub-pixel receptors as is typically the case (typically, each sub-pixel receptor corresponds to a color, and a combination of three represents a pixel). Instead, they can have only one sub-pixel receptor. This configuration improves energy utilization compared to using three sub-pixel receptors for receiving different colors, reducing energy loss.

[0061] Exemplarily, the imaging sensor 100 is a grayscale sensor. When forming the first image 111, the second image 121, and the third image 131, the grayscale sensor only needs to obtain the intensity of the pixels in each image. Then, when synthesizing the images, the corresponding colors of each image can be synthesized according to the intensity.

[0062] In an exemplary embodiment, the three phase compensating parts of the metasurface lens 200 specifically include: a first phase compensating part 210 having an operating wavelength of red light, a second phase compensating part 220 having an operating wavelength of green light, and a third phase compensating part 230 having an operating wavelength of blue light.

[0063] In an exemplary embodiment, the operating wavelength of the first phase compensator is 680.0 to 720.0 nm, the operating wavelength of the second phase compensator is 526.1 to 566.1 nm, and the operating wavelength of the third phase compensator is 514.8 to 544.8 nm.

[0064] For example, the first phase compensator has an operating wavelength of 700.0 nm, the second phase compensator has an operating wavelength of 546.1 nm, and the third phase compensator has an operating wavelength of 534.8 nm. The three images formed by these operating wavelengths are easy to synthesize, and the synthesized image has good color.

[0065] In an exemplary embodiment of the present application, the metasurface lens imaging device provided herein further includes three filters. Each filter is provided in correspondence with a phase compensator. The filter can be provided in the optical path of the corresponding phase compensator, for example, on the object side of the phase compensator, or between the phase compensator and the imaging sensor 100.

[0066] In an exemplary embodiment, the phase compensation portion may include at least one nanoantenna array. The nanoantenna array includes a plurality of nanoantennas. These nanoantennas may have a height in the direction of the optical axis Z. Generally speaking, the heights of these nanoantennas are not high and are basically consistent, so the metasurface lens 200 can be considered to have a plane. In the cross section of the optical axis Z, the nanoantenna may have various different shapes, such as circular, rectangular, etc. Exemplarily, the nanoantenna is longer in one direction and shorter in another perpendicular direction. Specifically, the nanoantenna has a long axis and a short axis that are perpendicular to each other, and the rotation angle of the nanoantenna is generally determined according to the long axis. Specifically, the rotation angle of the nanoantenna is set based on the position of the nanoantenna in the nanoantenna array in which it is located.

[0067] refer to Figure 3 and Figure 4 The first phase compensator 210 includes a first nanoantenna array 211, the center of which is located on the optical axis Z. The first nanoantenna array 211 includes a first nanoantenna 2111. The first nanoantenna 2111 has a rectangular shape within a cross-section along the optical axis Z, with a major axis H1 and a minor axis W1, and is located at a distance r1 from the center of the first nanoantenna array 211. Specifically, the intersection of the major axis H1 and the minor axis W1 can be considered the centroid of the first nanoantenna 211. The length of the line connecting the centroid and the center of the first nanoantenna array 211 is the distance r1. The length of the line connecting the centroid and the center of the first nanoantenna array 211 is the distance r2. The rotation angle of the first nanoantenna 2111, which is the angle between the major axis H1 and the major axis H2 of the second nanoantenna 2112, is determined based on the distance r1 and the distance r2 between the second nanoantenna 2112.

[0068] In an exemplary embodiment, among the nanoantennas at corresponding positions among the three phase compensators, the rotation angle of the phase compensator with the smallest operating wavelength is the largest, and the rotation angle of the phase compensator with the largest operating wavelength is the smallest.

[0069] For example, the operating wavelength of the first phase compensator 210 is the largest, the operating wavelength of the second phase compensator 220 is in the middle, and the operating wavelength of the third phase compensator 230 is the smallest. When the centers of the three phase compensators are all at the optical axis Z, for multiple nanoantennas at the same distance r from the center, the rotation angle of the nanoantennas at that location in the first nanoantenna array 211 of the first phase compensator 210 is the smallest, the rotation angle of the nanoantennas at that location in the second nanoantenna array of the second phase compensator 220 is in the middle, and the rotation angle of the nanoantennas at that location in the third nanoantenna array 231 of the third phase compensator 230 is the largest.

[0070] In an exemplary embodiment, the material of the phase compensating part includes an inorganic dielectric material.

[0071] Illustratively, the material of the phase compensator includes at least one of zinc sulfide, magnesium fluoride, titanium dioxide, zirconium oxide, silicon hydride, crystalline silicon, silicon nitride, amorphous silicon, gallium nitride, gallium phosphide, or gallium arsenide. Illustratively, the material of each phase compensator is one of the aforementioned materials, and the materials of different phase compensators may be different.

[0072] In an exemplary embodiment, the material of the phase compensating part includes a transparent organic material.

[0073] Exemplarily, the material of the phase compensating portion includes polymethyl methacrylate (PMMA).

[0074] Specifically, the material of the nano-antenna array is an inorganic dielectric material or a transparent organic material, and the material of the substrate is different from the material of the nano-antenna array. Exemplarily, the refractive index of the substrate material is lower than that of the material of the nano-antenna array.

[0075] exist Figure 1 Under the condition of the paraxial imaging, the phase compensation ΔΦ provided by the phase compensator to the incident light L1 satisfies the formula (1):

[0076]

[0077] Wherein, λ is the operating wavelength, f is the focal length of the metasurface lens 100 , r is the distance between each nanoantenna and the optical axis Z, k is an integer and in simplified case the value of k can be zero, and k reflects the number of rotations.

[0078] For example, for a rectangular nanoantenna, the rotation angle θ of its long axis satisfies formula (2) for the left-handed polarization component and the right-handed polarization component in the light:

[0079]

[0080] That's it.

[0081] Those skilled in the art will also appreciate that the shape of each nanoantenna is not limited to a rectangular parallelepiped. Instead, solid nanoantennas such as rectangular parallelepipeds, cylinders, or hemispheres can be used, or hollow or partially hollow nanoantennas with rectangular parallelepiped, cylinder, or hemisphere-shaped recesses or holes can be used to further fine-tune the phase, thereby achieving further effects such as eliminating chromatic aberration and polarization sensitivity. It should be noted that a nanoantenna can be composed of a combination of multiple solid or hollow nanoantennas of different sizes to form a single nanoantenna unit, and the combination of multiple nanoantenna units can achieve further effects such as eliminating chromatic aberration and polarization sensitivity.

[0082] For more complex nanoantenna structures, the phase compensation of the incident light L1 is not determined solely by the rotation angle, and is difficult to calculate analytically. Specifically, numerical simulation methods such as FDTD (finite difference time domain) and finite element method (FEM) can be used for analysis.

[0083] For example, a database of phase compensation units is established. Based on as many phase data points as possible within the range [0, 2π] for phase compensation, numerical simulation methods such as FDTD are used to calculate and store the phase compensation units corresponding to each phase data point in the database. The database is then iterated over all possible values ​​of the distance r, and at each value, the corresponding phase compensation unit in the database is searched for the desired phase compensation unit, which is then applied. To accommodate imaging with a wide field of view, phase compensation for different field of view angles also needs to account for the additional phase difference introduced by changes in the angle of incidence.

[0084] refer to Figure 5 For example, the operating wavelength λ1 of the first phase compensator 210 is 700 nm, the operating wavelength λ2 of the second phase compensator 220 is 546 nm, and the operating wavelength λ3 of the third phase compensator 230 is 436 nm. When the focal length f of the metasurface lens 200 satisfies f = 50 μm, the required phase compensation value at a distance r from the optical axis Z is shown in Table 1, where r is in μm and λ is in nm:

[0085] Table 1: Phase compensation values

[0086]

[0087]

[0088] When the value of r is 0 μm, the phase compensation value corresponding to each operating wavelength is also 0. Therefore, the phase compensation portion with a shorter operating wavelength needs to provide a phase compensation with a larger absolute value.

[0089] In an exemplary embodiment, the metasurface lens 200 includes a first sub-lens, a second sub-lens, and a third sub-lens; the first sub-lens includes a first phase compensating portion 210, the second sub-lens includes a second phase compensating portion 220, and the third sub-lens includes a third phase compensating portion 230. The metasurface lens 200 includes a plurality of sub-lenses that are pieced together.

[0090] The actual shape of the metasurface lens and the method of area division are not limited. It is only necessary to divide the plane where the metasurface lens is located into multiple separate areas. Figure 6 、 7 More examples are shown in FIG and 8. In addition, the division may take into account the size specifications of the actual device and the imaging sensor 100. The images at different imaging regions are then combined to form a color image.

[0091] For example, refer to Figure 6 The metasurface lens 200 is divided into three strip-shaped areas from left to right, namely the second phase compensation portion 220, the first phase compensation portion 210 and the third phase compensation portion 230.

[0092] For example, refer to Figure 7 The metasurface lens 200 is divided into three circular areas counterclockwise along the circumference of the optical axis Z, namely the first phase compensation portion 210 , the second phase compensation portion 220 and the third phase compensation portion 230 .

[0093] For example, refer to Figure 8 The metasurface lens 200 is divided into a “pink”-shaped area, including a first phase compensation portion 210 at the top, a second phase compensation portion 220 at the lower left, and a third phase compensation portion 230 at the lower right.

[0094] However, those skilled in the art will appreciate that the above embodiments are merely examples, and the metasurface lens 200 can be divided into three different forms, and correspondingly divided into three corresponding imaging regions on the imaging sensor, thereby forming an image in each imaging region.

[0095] refer to Figure 9 The embodiment of the present application further provides a method 1000 for imaging a metasurface lens, the method 1000 comprising the following steps:

[0096] S1010: Using three phase compensators, incident light is caused to form images in three imaging regions, respectively, with the three formed images corresponding one-to-one to the three phase compensators. The three phase compensators are disposed along the optical axis in an object-side direction of the three imaging regions, the three phase compensators are located at different positions in a cross section of the optical axis, the three phase compensators provide different phase compensations for the incident light, and the three imaging regions are located at different positions in the cross section of the optical axis and correspond one-to-one to the three phase compensators.

[0097] S1020: Synthesize three images. The three images can be extracted from the image. This method can generate images with small chromatic aberration.

[0098] In an exemplary embodiment, the operating wavelengths of the three phase compensating portions are red light, green light, and blue light, respectively.

[0099] In an exemplary embodiment, the operating wavelengths of the three phase compensating portions are 700.0 nm, 546.1 nm, and 534.8 nm, respectively.

[0100] In an exemplary embodiment, the method 1000 further includes: S1030 , filtering the three parts of light corresponding to the three phase compensation parts in the incident light respectively.

[0101] The present application also provides a method 2000 for forming a metasurface lens imaging device, comprising:

[0102] S2010 , forming an imaging sensor to have three imaging areas located at different positions in a cross section of the optical axis.

[0103] S2030, deploying a metasurface lens along the optical axis in the object-side direction of the imaging sensor, wherein the metasurface lens includes three phase compensation parts located at different positions in the cross-section of the optical axis, and the three phase compensation parts perform different phase compensations on the incident light, so that the incident light forms images in the three imaging areas respectively, and the three images formed correspond one-to-one to the three phase compensation parts.

[0104] S2050: Connecting a synthesizer to the imaging sensor for communication. The synthesizer is used to synthesize three images.

[0105] The method 2000 can easily manufacture an imaging device with small imaging chromatic aberration at a low cost.

[0106] In an exemplary embodiment, the method 2000 further includes:

[0107] In step S2020, a first phase compensator, a second phase compensator, and a third phase compensator are respectively provided on the first sub-lens, the second sub-lens, and the third sub-lens. The metasurface lens includes the first sub-lens, the second sub-lens, and the third sub-lens. The operating wavelengths of the three compensation mechanisms are red, green, and blue, respectively. This step may be performed before step S2030.

[0108] In an exemplary embodiment, the method 2000 further includes:

[0109] S2040: Setting a synthesizer to synthesize three images, specifically to synthesize a color image.

[0110] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of protection involved in this application is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also includes other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the technical concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions in this application.

Claims

1. A metasurface lens imaging device, characterized in that: include: An imaging sensor comprising three imaging regions distributed circumferentially and located at different positions in a cross section of the optical axis; a metasurface lens disposed along the optical axis in an object-side direction of the imaging sensor, and comprising three phase compensating portions distributed circumferentially and located at different positions in a cross section of the optical axis, wherein the three phase compensating portions perform different phase compensations on incident light, so that the incident light forms images in the three imaging regions, respectively, and the three formed images correspond one-to-one to the three phase compensating portions, and the operating wavelengths of the three phase compensating portions are different from each other; as well as a synthesizer for synthesizing the three images, The phase compensator comprises a nanoantenna array formed by a plurality of nanoantennas; the nanoantenna array has a center; a rotation angle is defined between the long axes of two radially adjacent nanoantennas in each nanoantenna array, and the rotation angle is determined based on the distance between the two nanoantennas and the center; Among the rotation angles of the nanoantenna at corresponding positions in the three phase compensation parts, the one corresponding to the phase compensation part with the smallest working wavelength is the largest, and the one corresponding to the phase compensation part with the largest working wavelength is the smallest.

2. The metasurface lens imaging device according to claim 1, wherein: Also includes: An aperture is arranged along the optical axis in the object side direction of the metasurface lens.

3. The metasurface lens imaging device according to claim 1, wherein: The three phase compensation units include: A first phase compensation unit, whose operating wavelength is a red light wavelength; A second phase compensation unit, whose operating wavelength is a green light wavelength; and The third phase compensation unit has an operating wavelength of blue light.

4. The metasurface lens imaging device according to claim 3, wherein: The operating wavelength of the first phase compensator is within 680.0 nm to 720.0 nm, the operating wavelength of the second phase compensator is within 526.0 nm to 566.0 nm, and the operating wavelength of the third phase compensator is within 515 nm to 555.0 nm.

5. The metasurface lens imaging device according to claim 4, wherein: The operating wavelength of the first phase compensating portion is 700.0 nm, the operating wavelength of the second phase compensating portion is 546.1 nm, and the operating wavelength of the third phase compensating portion is 534.8 nm.

6. The metasurface lens imaging device according to claim 1, wherein: It also includes three filters, which are arranged in a one-to-one correspondence with the three phase compensation parts and in the image side direction of the phase compensation part.

7. The metasurface lens imaging device according to claim 1, wherein: The nanoantenna has a long axis and a short axis that are perpendicular to each other in a cross section of the optical axis, and the orientation of the long axis of the nanoantenna is set based on the position of the nanoantenna in the nanoantenna array.

8. The metasurface lens imaging device according to claim 1, wherein: The imaging sensor is a grayscale sensor.

9. The metasurface lens imaging device according to claim 3, wherein: The metasurface lens includes a first sub-lens, a second sub-lens and a third sub-lens; The first sub-lens includes the first phase compensating portion, the second sub-lens includes the second phase compensating portion, and the third sub-lens includes the third phase compensating portion.

10. The metasurface lens imaging device according to claim 1, wherein: The phase compensation part is made of an inorganic dielectric material or a transparent organic material.

11. The metasurface lens imaging device according to claim 10, wherein: The material of the phase compensation part includes at least one of zinc sulfide, magnesium fluoride, titanium dioxide, zirconium oxide, silicon hydride, crystalline silicon, silicon nitride, amorphous silicon, gallium nitride, gallium phosphide or gallium arsenide.

12. The metasurface lens imaging device according to claim 10, wherein: The phase compensation portion is made of polymethyl methacrylate.

13. A metasurface lens imaging method, characterized in that: include: Using three phase compensators, incident light is caused to form images in three imaging regions, respectively, and the three formed images correspond one-to-one to the three phase compensators, wherein the three phase compensators are arranged along the optical axis in the object-side direction of the three imaging regions, the three phase compensators are distributed circumferentially in a cross section of the optical axis and are located at different positions, the three phase compensators perform different phase compensations on the incident light, the three phase compensators have different operating wavelengths, and the three imaging regions are distributed circumferentially in a cross section of the optical axis and are located at different positions; and Combining the three images, The phase compensator comprises a nanoantenna array formed by a plurality of nanoantennas; the nanoantenna array has a center; a rotation angle is defined between the long axes of two radially adjacent nanoantennas in each nanoantenna array, and the rotation angle is determined based on the distance between the two nanoantennas and the center; Among the rotation angles of the nanoantenna at corresponding positions in the three phase compensation parts, the one corresponding to the phase compensation part with the smallest working wavelength is the largest, and the one corresponding to the phase compensation part with the largest working wavelength is the smallest.

14. The metasurface lens imaging method according to claim 13, wherein: The operating wavelengths of the three phase compensation parts are respectively a red light wavelength, a green light wavelength and a blue light wavelength.

15. The metasurface lens imaging method according to claim 14, wherein: The operating wavelengths of the three phase compensation parts are respectively within 680.0 nm to 720.0 nm, within 526.0 nm to 566.0 nm, and within 515 nm to 555.0 nm.

16. The metasurface lens imaging method according to claim 15, wherein: The operating wavelengths of the three phase compensation parts are 700.0 nm, 546.1 nm and 534.8 nm respectively.

17. The metasurface lens imaging method according to claim 14, wherein: Also includes: The three parts of the incident light corresponding to the three phase compensation parts are filtered respectively.

18. A method for forming a metasurface lens imaging device, comprising: The imaging sensor is formed to have three imaging areas distributed in a circumferential direction and located at different positions in a cross section of the optical axis; A metasurface lens is disposed along the optical axis in an object-side direction of the imaging sensor, wherein the metasurface lens includes three phase compensation portions distributed circumferentially and located at different positions in a cross section of the optical axis, the three phase compensation portions performing different phase compensations on incident light, so that the incident light forms images in the three imaging regions, respectively, and the three formed images correspond one-to-one to the three phase compensation portions, and the operating wavelengths of the three phase compensation portions are different from each other; as well as a synthesizer communicatively connected to the imaging sensor, wherein the synthesizer is configured to synthesize the three images; The phase compensator comprises a nanoantenna array formed by a plurality of nanoantennas; the nanoantenna array has a center; a rotation angle is defined between the long axes of two radially adjacent nanoantennas in each nanoantenna array, and the rotation angle is determined based on the distance between the two nanoantennas and the center; Among the rotation angles of the nanoantenna at corresponding positions in the three phase compensation parts, the one corresponding to the phase compensation part with the smallest working wavelength is the largest, and the one corresponding to the phase compensation part with the largest working wavelength is the smallest.

19. The method according to claim 18, wherein The three phase compensation units include: A first phase compensation unit, whose operating wavelength is a red light wavelength; A second phase compensation unit, whose operating wavelength is a green light wavelength; and A third phase compensation unit, whose operating wavelength is a blue light wavelength; The metasurface lens includes a first sub-lens, a second sub-lens and a third sub-lens; The method further comprises: The first phase compensating portion, the second phase compensating portion, and the third phase compensating portion are respectively provided on the first sub-lens, the second sub-lens, and the third sub-lens.

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