A design method of polarization-insensitive synthetic aperture dispersion-achromatic superlens in mid-infrared waveband

Abstract

The application is a design method of a synthetic aperture discrete achromatic superlens in a middle infrared wave band which is polarization-insensitive. The application relates to the technical field of superlens, and determines the wave band range of the synthetic aperture discrete achromatic superlens, the size of a small-size lens, the numerical aperture in the synthetic aperture superlens and the shape of the synthetic aperture superlens; according to the discrete achromatic superlens, the phase and dispersion distribution required by all positions of the synthetic aperture superlens are determined; a center-symmetrical unit is used to construct a unit library of the phase and dispersion; the most suitable unit of each position of the superlens is obtained by screening according to the phase and dispersion required by the synthetic aperture superlens; and all the best units are arranged along the x-axis and the y-axis periodically with the center as the origin, so that the designed discrete achromatic synthetic aperture superlens is obtained. The application focuses on the synthetic aperture achromatic problem, and fills the gap that there is only a single-frequency point synthetic aperture lens design method but no synthetic aperture achromatic design method.

Description

Technical Field

[0001] This invention relates to the field of superlens technology, and is a design method for a synthetic aperture discrete achromatic superlens that is insensitive to polarization in the mid-infrared band. Background Technology

[0002] Lenses are key components in imaging systems. Traditional lenses are refracting lenses, which use the principle of refraction to focus light. However, traditional lenses are expensive, heavy, and bulky, hindering integration and portability, and contradicting the trend towards lighter and more integrated devices. The emergence of metalenses has propelled the development of lenses towards integration and portability. A metalens is a diffractive lens that, based on the generalized Snell's law, modulates the amplitude and phase of electromagnetic waves through elementary atoms, thereby enabling the focusing of electromagnetic waves or achieving other functions. This technology was recognized as one of the best discoveries by Science in 2016. Metalenses have evolved from single-frequency focusing towards achromatic lenses, but there are physical limitations between lens size, numerical aperture, and achromatic bandwidth, restricting their application scenarios. The emergence of discrete achromatic metalenses has relaxed these limitations, allowing for the design of larger achromatic metalenses. However, the fabrication of large-size metalenses is limited by the non-scalability of photolithography processes, and the imaging resolution is directly proportional to the lens aperture size. To address this issue, researchers have used synthetic aperture metalenses, which utilize multiple small-aperture lenses to achieve the equivalent resolution of a lens with the same aperture. However, the designed lenses are all single-frequency lenses. Therefore, this invention proposes a design method for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic metalens. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a design method for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens.

[0004] This invention provides the following technical solutions:

[0005] A method for designing a mid-infrared polarization-insensitive discrete achromatic superlens with a synthetic aperture, the method comprising the following steps:

[0006] Step 1: Determine the operating band range of the synthetic aperture discrete achromatic superlens, the size of the small lens, the numerical aperture, and the shape of the synthetic aperture superlens;

[0007] Step 2: Based on the discrete achromatic superlens, determine the phase and dispersion distribution required for all positions of the synthesized aperture superlens;

[0008] Step 3: Construct a unit library that satisfies the phase and dispersion requirements of Step 2 using centrosymmetric elements;

[0009] Step 4: Select the most suitable unit for each position of the superlens according to the phase and dispersion required for the synthetic aperture superlens, thereby determining the shape, type and size of the unit at each position;

[0010] Step 5: With the center as the origin, arrange all the best units periodically along the x-axis and y-axis to obtain the designed discrete achromatic synthetic aperture superlens.

[0011] Preferably, step 2 specifically comprises:

[0012] When a beam of light with wavelength λ shines on a superlens, and the focal length of the superlens is set to f, the phase distribution of the small lenses in the synthetic aperture superlens satisfies:

[0013]

[0014] Where θ and φ are the angles between the focal point and the center point of the small lens, and (x, y) are the coordinates of the center of any unit of the superlens;

[0015] The group delay distribution that each small lens should satisfy is:

[0016]

[0017] Where GD is the group delay, c is the speed of light, f is the focal length, (x, y) is the coordinate of any unit of the superlens, and θ and φ are the angles between the focal point and the center point of the microlens.

[0018] The phase distribution of the superlens is obtained using a discrete achromatic superlens:

[0019]

[0020] Where, ω c Let $\mathbf{R}$ be the center frequency, $GD$ be the group delay, $r$ be the distance from any element of the superlens to the origin, $Δω$ be the frequency interval of the extension, $ΔGD$ be the dispersion of the periodic extension, and $N$ be the distance from $\mathbf{R}$ to the origin. c ) / Δω.

[0021] Preferably, Δω=2*π*11.4285*10 12 rad / s, mod is a modulo function, and mod(GD, ΔGD) is the remainder after dividing GD by ΔGD.

[0022] Preferably, a polarization-insensitive element library is constructed to meet the required dispersion and phase requirements. Elements are then selected using an error function Error(x, y; n).

[0023]

[0024] in, For an ideal frequency ω k At that time, the amplitude and phase distribution at a radius of r, For all elements in the element library, the frequency is ω k The amplitude and phase distribution at that time, M is the total number of selected frequency points in the frequency band, and k is the current frequency.

[0025] Preferably, the unit is selected according to the strategy of minimizing the error function. For the sake of calculation simplicity, M=15 frequency points in the range of 60THz-100THz are used for calculation, and the result with the smallest error is taken.

[0026] Preferably, the types of medium columns in the superlens include seven types: square column, air, square ring, square ring column, cross shape, square ring cross, and square cross ring, and all medium columns have the same height H and period P.

[0027] Preferably, the cross-shaped synthetic aperture superlens, composed of five small lenses with a size of 500μm, is achromatic within the range of 3μm-5μm. The numerical aperture of the large-size lens equivalent to the synthetic aperture superlens is 0.42, and the diameter is 3mm.

[0028] A design system for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens, the system comprising:

[0029] The parameter determination module determines the operating band range of the synthetic aperture discrete achromatic superlens, the size of the small-sized lens, the numerical aperture, and the shape of the synthetic aperture superlens.

[0030] A phase and dispersion distribution determination module determines the required phase and dispersion distribution for all positions of the synthetic aperture superlens based on the discrete achromatic superlens.

[0031] A cell library construction module, which uses centrally symmetric cells to construct a cell library that satisfies the required phase and dispersion;

[0032] The screening module filters according to the phase and dispersion required for the synthetic aperture superlens to obtain the most suitable unit at each position of the superlens, thereby determining the shape, type and size of the unit at each position;

[0033] The design module arranges all the best units periodically along the x-axis and y-axis with the center as the origin to obtain the designed discrete achromatic synthetic aperture superlens.

[0034] A computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement a design method for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens.

[0035] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement a design method for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens.

[0036] The present invention has the following beneficial effects:

[0037] Compared with the prior art, the present invention:

[0038] Compared to existing technologies, this invention primarily focuses on the achromatic problem of synthetic aperture lenses, filling the gap in current methods that only offer single-frequency synthetic aperture lens design but lack achromatic synthetic aperture lens design methods. By using several small-sized superlenses within the 3μm-5μm range, the resolution of a large-sized superlens can be equivalently obtained. Using the proposed algorithm, a cross-shaped synthetic aperture superlens, composed of five 500μm small lenses, was designed to achieve achromatic resolution within the 3μm-5μm range. The numerical aperture of the large-sized lens equivalent to the synthetic aperture superlens is 0.42, and its diameter is 3mm. Attached Figure Description

[0039] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0040] Figure 1 The flowchart shown is a method of the present invention;

[0041] Figure 2 The diagram shown is a schematic representation of the unit library constructed according to the present invention;

[0042] Figure 3 The diagram shown is a model diagram of the construction of this invention;

[0043] Figure 4 The diagram shown is a schematic of the synthetic aperture superlens constructed according to the present invention;

[0044] Figure 5 The diagram shows the XZ plane energy distribution and the XY plane energy distribution at the focal point according to the present invention.

[0045] Figure 6The present invention includes the MTF of small lens theory and simulation in synthetic aperture lens, the MTF of synthetic aperture lens theory and simulation, and the MTF of large-size lens equivalent to synthetic aperture lens. Detailed Implementation

[0046] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] The present invention will be described in detail below with reference to specific embodiments. Specific Implementation Example 1:

[0052] according to Figures 1 to 6 As shown, the specific optimized technical solution adopted by the present invention to solve the above-mentioned technical problems is: The present invention relates to a design method for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens.

[0053] A method for designing a mid-infrared polarization-insensitive discrete achromatic superlens with a synthetic aperture, the method comprising the following steps:

[0054] Step 1: Determine the operating band range of the synthetic aperture discrete achromatic superlens, the size of the small lens, the numerical aperture, and the shape of the synthetic aperture superlens;

[0055] Step 2: Based on the discrete achromatic superlens, determine the phase and dispersion distribution required for all positions of the synthesized aperture superlens;

[0056] Step 3: Construct a unit library that satisfies the phase and dispersion requirements of Step 2 using centrosymmetric elements;

[0057] Step 4: Select the most suitable unit for each position of the superlens according to the phase and dispersion required for the synthetic aperture superlens, thereby determining the shape, type and size of the unit at each position;

[0058] Step 5: With the center as the origin, arrange all the best units periodically along the x-axis and y-axis to obtain the designed discrete achromatic synthetic aperture superlens. Specific Implementation Example 2:

[0060] The only difference between Embodiment 2 and Embodiment 1 of this application is that:

[0061] Step 2 specifically involves:

[0062] When a beam of light with wavelength λ shines on a superlens, and the focal length of the superlens is set to f, the phase distribution of the small lenses in the synthetic aperture superlens satisfies:

[0063]

[0064] Where θ and φ are the angles between the focal point and the center point of the small lens, and (x, y) are the coordinates of the center of any unit of the superlens;

[0065] The group delay distribution that each small lens should satisfy is:

[0066]

[0067] Where GD is the group delay, c is the speed of light, f is the focal length, (x, y) is the coordinate of any unit of the superlens, and θ and φ are the angles between the focal point and the center point of the microlens.

[0068] The phase distribution of the superlens is obtained using a discrete achromatic superlens:

[0069]

[0070] Where, ω c Let $\mathbf{R}$ be the center frequency, $GD$ be the group delay, $r$ be the distance from any element of the superlens to the origin, $Δω$ be the frequency interval of the extension, $ΔGD$ be the dispersion of the periodic extension, and $N$ be the distance from $\mathbf{R}$ to the origin. c ) / Δω. Specific Implementation Example 3:

[0072] The only difference between Embodiment 3 and Embodiment 2 of this application is that:

[0073] Δω=2*π*11.4285*10 12 rad / s, mod is a modulo function, and mod(GD, ΔGD) is the remainder after dividing GD by ΔGD. Specific Implementation Example 4:

[0075] The only difference between Embodiment 4 and Embodiment 3 of this application is that:

[0076] A polarization-insensitive element library is constructed to meet the required dispersion and phase requirements. Elements are then selected using an error function Error(x, y; n).

[0077]

[0078] in, For an ideal frequency ω k At that time, the amplitude and phase distribution at a radius of r, For all elements in the element library, the frequency is ω k The amplitude and phase distribution at that time, M is the total number of selected frequency points in the frequency band, and k is the current frequency. Specific Implementation Example 5:

[0080] The difference between Embodiment 5 and Embodiment 4 of the present invention lies only in:

[0081] The unit is selected according to the strategy of minimizing the error function. For the sake of calculation simplicity, M=15 frequency points in the range of 60THz-100THz are used for calculation, and the result with the minimum error is taken. Specific Implementation Example Six:

[0083] The difference between Embodiment Six and Embodiment Five of the present invention lies only in:

[0084] There are seven types of medium pillars for superlenses: square pillar, air, square ring, square ring pillar, cross, square ring cross, and square cross ring. All medium pillars have the same height H and period P. Specific Implementation Example 7:

[0086] The difference between Embodiment Seven and Embodiment Six of the present invention lies only in:

[0087] A cross-shaped synthetic aperture superlens composed of five small lenses with a size of 500μm is used in the 3μm-5μm achromatic range. The numerical aperture of the large lens equivalent to the synthetic aperture superlens is 0.42, and the diameter is 3mm. Specific Implementation Example 8:

[0089] The difference between Embodiment 8 and Embodiment 7 of the present invention lies only in:

[0090] This invention provides a design system for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens, the system comprising:

[0091] The parameter determination module determines the operating band range of the synthetic aperture discrete achromatic superlens, the size of the small-sized lens, the numerical aperture, and the shape of the synthetic aperture superlens.

[0092] A phase and dispersion distribution determination module determines the required phase and dispersion distribution for all positions of the synthetic aperture superlens based on the discrete achromatic superlens.

[0093] A cell library construction module, which uses centrally symmetric cells to construct a cell library that satisfies the required phase and dispersion;

[0094] The screening module filters according to the phase and dispersion required for the synthetic aperture superlens to obtain the most suitable unit at each position of the superlens, thereby determining the shape, type and size of the unit at each position;

[0095] The design module arranges all the best units periodically along the x-axis and y-axis with the center as the origin to obtain the designed discrete achromatic synthetic aperture superlens. Specific Implementation Example Nine:

[0097] The difference between Embodiment Nine and Embodiment Eight of the present invention lies only in:

[0098] The present invention provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement a design method for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens.

[0099] The method includes the following steps:

[0100] Step 1: Determine the operating band range of the synthetic aperture discrete achromatic superlens, the size of the small lens, the numerical aperture, and the shape of the synthetic aperture superlens;

[0101] Step 2: Based on the discrete achromatic superlens, determine the phase and dispersion distribution required for all positions of the synthesized aperture superlens;

[0102] Step 3: Construct a unit library that satisfies the phase and dispersion requirements of Step 2 using centrosymmetric elements;

[0103] Step 4: Select the most suitable unit for each position of the superlens according to the phase and dispersion required for the synthetic aperture superlens, thereby determining the shape, type and size of the unit at each position;

[0104] Step 5: With the center as the origin, arrange all the best units periodically along the x-axis and y-axis to obtain the designed discrete achromatic synthetic aperture superlens. Specific Implementation Example 10:

[0106] The only difference between Embodiment 10 and Embodiment 9 of the present invention is that:

[0107] The present invention provides a computer device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements a design method for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens.

[0108] The method includes the following steps:

[0109] Step 1: Determine the operating band range of the synthetic aperture discrete achromatic superlens, the size of the small lens, the numerical aperture, and the shape of the synthetic aperture superlens;

[0110] Step 2: Based on the discrete achromatic superlens, determine the phase and dispersion distribution required for all positions of the synthesized aperture superlens;

[0111] Step 3: Construct a unit library that satisfies the phase and dispersion requirements of Step 2 using centrosymmetric elements;

[0112] Step 4: Select the most suitable unit for each position of the superlens according to the phase and dispersion required for the synthetic aperture superlens, thereby determining the shape, type and size of the unit at each position;

[0113] Step 5: With the center as the origin, arrange all the best units periodically along the x-axis and y-axis to obtain the designed discrete achromatic synthetic aperture superlens. Specific Implementation Example Eleven:

[0115] The only difference between Embodiment Eleven and Embodiment Ten of this invention is that:

[0116] Step 1 of this invention: Determine the operating band range of the synthetic aperture discrete achromatic superlens, the size of the small lens in the synthetic aperture superlens, the numerical aperture, and the shape of the synthetic aperture superlens.

[0117] Step 2: Based on the theory of discrete achromatic superlenses, obtain the phase and dispersion distribution required for all positions of the synthesized aperture superlens.

[0118] When a beam of light with wavelength λ shines on a superlens, the beam must satisfy a hyperbolic phase distribution to be focused. Assuming the focal length of the superlens is f, the phase distribution of the small lenses in the synthetic aperture superlens should satisfy:

[0119]

[0120] Where θ and φ are the angles between the focal point and the center of the miniature lens, and (x, y) are the coordinates of the center of any unit cell of the superlens. The group delay distribution that each miniature lens should satisfy is:

[0121]

[0122] Where GD is the group delay, c is the speed of light, f is the focal length, (x, y) are the coordinates of any element of the superlens, and θ and φ are the angles between the focal point and the center of the miniature lens. It can be seen that the group delay is a constant independent of frequency.

[0123] The phase distribution of the superlens can be obtained using the theory of discrete achromatic superlenses:

[0124]

[0125] ω in the formula c Let $\mathbf{R}$ be the center frequency, $GD$ be the group delay, $r$ be the distance from any element of the superlens to the origin, $Δω$ be the frequency interval of the extension, $ΔGD$ be the dispersion of the periodic extension, and $N$ be the distance from $\mathbf{R}$ to the origin. c ) / Δω.

[0126] Step 3: Construct a unit cell library that satisfies the phase and dispersion requirements of Step 2 using centrosymmetric elements.

[0127] Step 4: Based on the phase and dispersion requirements of the synthesized aperture superlens, the most suitable unit cells for each location of the superlens are selected, thus determining the shape, type, and size of each unit cell. There are seven types of medium pillars for the superlens: square pillar, air, square ring, square ring pillar, cross-shaped, square ring cross, and square cross ring. All medium pillars have the same height H and period P.

[0128] Step 5: Using the center as the origin, arrange all the optimal units periodically along the x-axis and y-axis to obtain the designed discrete achromatic synthetic aperture superlens.

[0129] Figure 1 This is a flowchart of the algorithm.

[0130] Figure 2 The unit library to be built.

[0131] Figure 3The model diagram includes an overall view of the synthetic aperture lens with a diameter of 1, a distribution diagram of the central local unit of the central small lens, a top view of the central local unit of the central small lens, a distribution diagram of the central local unit of the surrounding small lenses, a top view of the central local unit of the surrounding small lenses, 1 is the dielectric pillar, and 2 is the dielectric substrate.

[0132] Figure 4 The image shows the focal length distribution of the constructed synthetic aperture superlens in the 3μm-5μm range. The horizontal line represents the continuous achromatic focal length, with a value of 3.241mm. The red dashed line represents the discrete achromatic focal length, with a maximum error of 8.4% compared to the continuous achromatic focal length.

[0133] Figure 5 Let X be the energy distribution in the XZ plane and the energy distribution in the XY plane at the focal point.

[0134] Figure 6 This includes the theoretical and simulated MTF of small lenses in synthetic aperture lenses, the theoretical and simulated MTF of synthetic aperture lenses, and the theoretical and simulated MTF of large-size lenses equivalent to synthetic aperture lenses.

[0135] Compared to existing inventions, this invention primarily focuses on the achromatic problem of synthetic aperture lenses, filling the gap in current methods that only offer single-frequency synthetic aperture lens design but lack achromatic synthetic aperture lens design methods. By using several small-sized superlenses within the 3μm-5μm range, the resolution of a large-sized superlens can be equivalently obtained. Using the proposed algorithm, a cross-shaped synthetic aperture superlens, consisting of five 500μm small lenses, was designed to achieve achromatic resolution within the 3μm-5μm range. The numerical aperture of the large-sized lens equivalent to the synthetic aperture superlens is 0.42, and the diameter is 3mm. Specific Implementation Example Twelve:

[0137] The only difference between Embodiment Twelve and Embodiment Eleven of the present invention is that:

[0138] This invention first determines that the working wavelength range of the synthetic aperture discrete achromatic superlens is 3μm-5μm, the radius of the small-sized lens in the synthetic aperture superlens is 500μm, the numerical aperture is 0.27, and the shape of the synthetic aperture superlens is selected as cross-shaped.

[0139] When a beam of light with wavelength λ shines on a superlens, the beam must satisfy a hyperbolic phase distribution to be focused. Assuming the focal length of the superlens is f, the phase distribution of the small lenses in the synthetic aperture superlens should satisfy:

[0140]

[0141] This allows us to determine the phase distribution of the five miniature lenses in the cross-shaped synthetic aperture superlens. θ and φ are the angles between the focal point and the center of each miniature lens, and (x, y) are the coordinates of any unit center of the superlens. This is used to construct a discrete achromatic superlens. It expands into a Taylor series around ωc.

[0142]

[0143] Where φ(x, y, ω) c ) represents the center frequency ω c The phase distribution below, This represents the group delay phase distribution, where For group delay distribution, O(ω) 2 ) is the higher-order modulus. Since the element dispersion can be approximated as linear, the higher-order modulus is taken as 0.

[0144] The group delay distribution that each small lens should satisfy is:

[0145]

[0146] Where GD is the group delay, c is the speed of light, f is the focal length, (x, y) are the coordinates of any element of the superlens, and θ and φ are the angles between the focal point and the center of the miniature lens. It can be seen that the group delay is a constant independent of frequency.

[0147] The phase distribution of the superlens can be obtained using the theory of discrete achromatic superlenses:

[0148]

[0149] ω in the formula c Let $\mathbf{R}$ be the center frequency, $GD$ be the group delay, $r$ be the distance from any element of the superlens to the origin, $Δω$ be the frequency interval of the extension, $ΔGD$ be the dispersion of the periodic extension, and $N$ be the distance from $\mathbf{R}$ to the origin. c ) / Δω. Take Δω=2*π*11.4285*10 here 12 rad / s, Additionally, mod is a modulo function, where mod(GD, ΔGD) is the remainder after dividing GD by ΔGD.

[0150] Then, a polarization-insensitive element library is constructed to meet the required dispersion and phase requirements. Next, element selection is performed, introducing an error function Error(x, y; n) during the selection process.

[0151]

[0152] (x, y) are the coordinates of a point on the surface of the superlens. For an ideal frequency ω k At that time, the amplitude and phase distribution at a radius of r, For all elements in the element library, the frequency is ω k The amplitude and phase distribution at that time. M is the total number of frequency points selected within the frequency band, and k is the current frequency. Following the strategy of minimizing the error function, the units are selected. For simplicity, M = 15 frequency points within the 60THz-100THz range are used for calculation, and the result with the smallest error is taken.

[0153] Then, the optimal cells at each position are periodically arranged along the x-axis and y-axis to obtain the designed discrete achromatic synthetic aperture superlens, as shown in the figure. Figure 3 As shown.

[0154] Then, the results obtained from the screening were simulated to obtain the achromatic color difference result as follows: Figure 4 , Figure 5 As shown. Additionally, the MTF, which represents the lens's imaging capability, was obtained, such as... Figure 6 As shown.

[0155] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or N embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of the present invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified. Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0156] The above description is merely a preferred embodiment of a design method for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens. The scope of protection for this design method is not limited to the above embodiments; all technical solutions falling within this conceptual framework are within the scope of protection of this invention. It should be noted that for those skilled in the art, any improvements and variations made without departing from the principles of this invention should also be considered within the scope of protection of this invention.

Claims

1. A design method for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens, characterized by: The method includes the following steps: Step 1: Determine the operating band range of the synthetic aperture discrete achromatic superlens, the size of the small lens in the synthetic aperture superlens, the numerical aperture, and the shape of the synthetic aperture superlens; Step 2: Based on the discrete achromatic superlens, determine the phase and dispersion distribution required for all positions of the synthesized aperture superlens; Step 3: Construct a unit library that satisfies the phase and dispersion requirements of Step 2 using centrosymmetric elements; Step 4: Select the most suitable unit for each position of the superlens according to the phase and dispersion required for the synthetic aperture superlens, thereby determining the shape, type and size of the unit at each position; Step 5: With the center as the origin, arrange all the best units periodically along the x-axis and y-axis to obtain the designed discrete achromatic synthetic aperture superlens; Step 2 specifically involves: When a beam of light with wavelength λ shines on a superlens, and the focal length of the superlens is set to f, the phase distribution of the small lenses in the synthetic aperture superlens satisfies: Where θ and φ are the angles between the focal point and the center point of the small lens, and (x, y) are the coordinates of the center of any unit of the superlens; The group delay distribution that each small lens should satisfy is: Where GD is the group delay, c is the speed of light, f is the focal length, (x, y) is the coordinate of any unit of the superlens, and θ and φ are the angles between the focal point and the center point of the microlens. The phase distribution of the superlens is obtained using a discrete achromatic superlens: Where, ω c Let $\mathbf{R}$ be the center frequency, $GD$ be the group delay, $r$ be the distance from any element of the superlens to the origin, $Δω$ be the frequency interval of the extension, $ΔGD$ be the dispersion of the periodic extension, and $N$ be the distance from $\mathbf{R}$ to $\mathbf{R}$. c ) / Δω, mod(GD, ΔGD) is the remainder after dividing GD by ΔGD.

2. The method according to claim 1, characterized in that: Δω=2*π*11.4285*10 12 rad / s, mod is a modulo function.

3. The method according to claim 1, characterized in that: Construct a polarization-insensitive cell library that meets the required dispersion and phase requirements, and perform cell selection. In the cell selection process, introduce an error function Error(x, y). n)： in, For an ideal frequency ω k At that time, the amplitude and phase distribution at a radius of r, For all elements in the element library, the frequency is ω k The amplitude and phase distribution at time, where k is the current frequency.

4. The method according to claim 3, characterized in that: The unit is selected according to the strategy of minimizing the error function. For the sake of calculation simplicity, M=15 frequency points in the range of 60THz-100THz are used for calculation, and the result with the minimum error is taken.

5. The method according to claim 1, characterized in that: There are seven types of medium pillars for superlenses: square pillar, air, square ring, square ring pillar, cross, square ring cross, and square cross ring. All medium pillars have the same height H and period P.

6. The method according to claim 5, characterized in that: A cross-shaped synthetic aperture superlens composed of five small lenses with a size of 500μm is used in the 3μm-5μm achromatic range. The numerical aperture of the large lens equivalent to the synthetic aperture superlens is 0.42, and the diameter is 3mm.

7. A design system for a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens, the system operating based on the design method of a mid-infrared polarization-insensitive synthetic aperture discrete achromatic superlens according to claim 1, characterized in that: The system includes: The parameter determination module determines the operating band range of the synthetic aperture discrete achromatic superlens, the size of the small-sized lens, the numerical aperture, and the shape of the synthetic aperture superlens. A phase and dispersion distribution determination module determines the required phase and dispersion distribution for all positions of the synthetic aperture superlens based on the discrete achromatic superlens. A cell library construction module, which uses centrally symmetric cells to construct a cell library that satisfies the required phase and dispersion; The screening module filters according to the phase and dispersion required for the synthetic aperture superlens to obtain the optimal unit at each position of the superlens, thereby determining the shape, type and size of each unit at each position; The design module arranges all the best units periodically along the x-axis and y-axis with the center as the origin to obtain the designed discrete achromatic synthetic aperture superlens.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method as claimed in any one of claims 1-6.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the method of any one of claims 1-6.

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