WO2024066608A1 - 一种超表面的设计方法、装置及电子设备 - Google Patents

一种超表面的设计方法、装置及电子设备 Download PDF

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WO2024066608A1
WO2024066608A1 PCT/CN2023/104814 CN2023104814W WO2024066608A1 WO 2024066608 A1 WO2024066608 A1 WO 2024066608A1 CN 2023104814 W CN2023104814 W CN 2023104814W WO 2024066608 A1 WO2024066608 A1 WO 2024066608A1
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nanostructure
target
nanostructures
transmittance
wide
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PCT/CN2023/104814
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English (en)
French (fr)
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陈建发
郝成龙
谭凤泽
朱健
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深圳迈塔兰斯科技有限公司
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0012—Optical design, e.g. procedures, algorithms, optimisation routines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B2207/00—Coding scheme for general features or characteristics of optical elements and systems of subclass G02B, but not including elements and systems which would be classified in G02B6/00 and subgroups
    • G02B2207/101—Nanooptics

Definitions

  • the present invention relates to the field of metasurface technology, and in particular to a metasurface design method, device, electronic device and computer-readable storage medium.
  • the phase control mechanism of metasurfaces is generally based on normal incidence or small-angle incidence, and less consideration is given to optical performance under large-angle oblique incidence.
  • large-angle incident light needs to be considered.
  • the metasurface will have a problem of reduced imaging quality, which is partly due to the low transmittance and phase mutation caused by the resonant response of some structural units (nanostructures) under oblique incidence.
  • some silicon nanocylinders will have a resonant response to oblique incident light, resulting in changes in transmittance and phase mutations, which ultimately makes the designed metasurface unsuitable for scenes with large-angle incidence.
  • the embodiments of the present invention provide a design method, device, electronic device and computer-readable storage medium for a metasurface.
  • an embodiment of the present invention provides a method for designing a metasurface, comprising:
  • n first nanostructures wherein different first nanostructures have different modulation phases for main incident light; the main incident light is incident light at a main incident angle, and n ⁇ 2;
  • the initial target nanostructure is the corresponding first nanostructure
  • the updating operation includes:
  • the performance information comprising performance parameters of the target nanostructure under incident light at different incident angles, the performance parameters comprising transmittance and/or modulation phase; the performance information of the target nanostructure is used to determine whether the target nanostructure meets the wide-angle imaging requirement;
  • a new second nanostructure is selected and the target nanostructure that does not meet the wide-angle imaging requirements is replaced by the second nanostructure to generate a new nanostructure set; the second nanostructure and the target nanostructure that does not meet the wide-angle imaging requirements have the same modulation phase for the main incident light, and the second nanostructure and the target nanostructure that does not meet the wide-angle imaging requirements have different shapes.
  • the wide-angle imaging requirement when the performance parameter includes transmittance, includes a wide-angle imaging transmittance requirement; the greater the transmittance of the target nanostructure under incident light at different incident angles, the more it can meet the wide-angle imaging transmittance requirement.
  • the updating operation further includes:
  • the first average transmittance is a weighted average of transmittances of a plurality of the target nanostructures under incident light at the incident angle
  • At least one of the first average transmittances is lower than a first preset transmittance threshold, it is determined that at least one target nanostructure does not meet the wide-angle imaging transmittance requirement.
  • determining the first average transmittance corresponding to each of the incident angles includes:
  • the transmittance of the incident light at the incident angle is weighted to obtain a first average transmittance corresponding to the incident angle; the weights of different target nanostructures are the same, or the weight of the target nanostructure is positively correlated with the number of nanostructures in the metasurface corresponding to the same modulation phase as the target nanostructure;
  • the first average transmittance satisfies:
  • w i represents the weight of the i-th target nanostructure
  • ti ,j represents the transmittance of the i-th target nanostructure under the incident light at the j-th incident angle
  • w i represents the weight of the i-th target nanostructure
  • ti ,j represents the transmittance of the i-th target nanostructure under the incident light at the j-th incident angle
  • w i represents the weight of the i-th target nanostructure
  • ti ,j represents the transmittance of the i-th target nanostructure under the incident light at the j-th incident angle
  • determining that at least one target nanostructure does not meet the wide-angle imaging transmittance requirement includes:
  • the target nanostructure with the lowest transmittance or the lowest second average transmittance is regarded as the target nanostructure that does not meet the wide-angle imaging transmittance requirement; the second average transmittance is the average transmittance of the target nanostructure under incident light of multiple incident angles.
  • the updating operation further includes:
  • the first average transmittances are not lower than a first preset transmittance threshold, and the first average transmittance corresponding to the main incident angle is not lower than a second preset transmittance threshold, it is determined that all of the target nanostructures meet the wide-angle imaging transmittance requirement; and the second preset transmittance threshold is greater than the first preset transmittance threshold.
  • the updating operation further includes:
  • the transmission parameter of the target nanostructure includes: a minimum value of the transmittance of the target nanostructure, or a second average transmittance of the target nanostructure; the second average transmittance is an average value of the transmittance of the target nanostructure under incident light of multiple incident angles;
  • the target nanostructures having the lowest transmission parameters are regarded as target nanostructures that do not meet the wide-angle imaging transmittance requirement.
  • the wide-angle imaging requirement includes a wide-angle imaging phase requirement; the smaller the phase gradient of the target nanostructure, the more it can meet the wide-angle imaging phase requirement; wherein the phase gradient of the target nanostructure is used to indicate the degree of change in the modulation phase of the target nanostructure.
  • the updating operation further includes:
  • phase gradient of each of the target nanostructures comprising: a degree of variation of a modulation phase difference between the target nanostructure and other adjacent target nanostructures as the incident angle changes, and/or a degree of variation of a modulation phase of the target nanostructure as the incident angle changes;
  • the phase gradient of the target nanostructure is higher than the corresponding preset gradient threshold, it is determined that the target nanostructure with the phase gradient higher than the preset gradient threshold does not meet the wide-angle imaging phase requirement.
  • the updating operation further includes:
  • the method before the cyclically performing the update operation on the nanostructure set including the n target nanostructures, the method further includes:
  • Performance analysis is performed on a plurality of nanostructures of different shapes to determine performance information of each of the nanostructures.
  • the performing performance analysis on a plurality of nanostructures of different shapes includes:
  • a test metasurface corresponding to the nanostructure is formed by using a plurality of the same nanostructures, and incident light is emitted to the test metasurface at different incident angles;
  • the performance parameters of the test metasurface under incident light at different incident angles are used as the corresponding performance parameters of the nanostructure.
  • the second nanostructure has a different shape from the first nanostructure having the same modulation phase for the main incident light and other previously selected second nanostructures having the same modulation phase for the main incident light.
  • the main incident angle is 0° ⁇ , where ⁇ represents an angle value within an allowable error range.
  • the modulation phases of the n first nanostructures on the main incident light can at least cover 0 to 2 ⁇ .
  • n is greater than or equal to 8.
  • both the first nanostructure and the second nanostructure are polarization-dependent structures; or both the first nanostructure and the second nanostructure are polarization-independent structures.
  • an embodiment of the present invention further provides a metasurface design device, comprising:
  • An initial module used to determine n first nanostructures, where different first nanostructures have different modulation phases for main incident light; the main incident light is incident light at a main incident angle, and n ⁇ 2;
  • An updating module used for cyclically performing an updating operation on a nanostructure set including n target nanostructures until all the target nanostructures in the nanostructure set meet the wide-angle imaging requirement; the initial target nanostructure is the corresponding first nanostructure;
  • a design module for designing a metasurface based on the nanostructure set
  • the update module includes an acquisition unit and an update unit
  • the acquisition unit is used to acquire performance information of each of the target nanostructures, wherein the performance information includes performance parameters of the target nanostructure under incident light at different incident angles, wherein the performance parameters include transmittance and/or modulation phase; the performance information of the target nanostructure is used to determine whether the target nanostructure meets the wide-angle imaging requirement;
  • the updating unit is used to, when there is a target nanostructure that does not meet the wide-angle imaging requirement, select a new second nanostructure and replace the target nanostructure that does not meet the wide-angle imaging requirement with the second nanostructure to generate a new nanostructure set; the second nanostructure and the target nanostructure that does not meet the wide-angle imaging requirement have the same modulation phase for the main incident light, and the second nanostructure and the target nanostructure that does not meet the wide-angle imaging requirement have different shapes.
  • an embodiment of the present invention provides an electronic device, comprising a bus, a transceiver, a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the transceiver, the memory, and the processor are connected via the bus, and the computer program, when executed by the processor, implements the steps in the method for designing a metasurface described in any one of the above.
  • an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps in any one of the above-described methods for designing a metasurface are implemented.
  • the metasurface design method, device, electronic device and computer-readable storage medium taken the modulation phase of the main incident light as a reference, select n nanostructures with different modulation phases (such as the first nanostructure), determine whether the selected nanostructure meets the wide-angle imaging requirements by analyzing its performance parameters under incident light at different incident angles, and replace the nanostructures that do not meet the wide-angle imaging requirements with nanostructures of other shapes to achieve updating, so that nanostructures with smaller resonant response can be found, and then the updated n nanostructures are used to design a metasurface.
  • the designed metasurface has a relatively stable modulation effect on incident light at different incident angles, has good overall performance, can be suitable for wide-angle imaging scenarios, and can improve the wide-angle imaging quality.
  • FIG1 shows a flow chart of a method for designing a metasurface provided by an embodiment of the present invention
  • FIG2 shows a detailed flow chart of a method for designing a metasurface provided by an embodiment of the present invention
  • FIG3 shows a schematic structural diagram of a cylindrical nanostructure provided by an embodiment of the present invention
  • FIG4A shows the transmittance of eight cylindrical target nanostructures provided by an embodiment of the present invention at different incident angles
  • FIG4B shows the phases of eight cylindrical target nanostructures provided by an embodiment of the present invention at different incident angles
  • FIG5A shows the transmittance and phase of different target nanostructures at an incident angle of 0° provided by an embodiment of the present invention
  • FIG5B shows the transmittance and phase of different target nanostructures at an incident angle of 30° provided by an embodiment of the present invention
  • FIG6 shows a schematic structural diagram of a cross-column-shaped nanostructure provided by an embodiment of the present invention
  • FIG7 is a schematic diagram showing a method of replacing a target nanostructure with a sequence number of 3 to form a new nanostructure set provided by an embodiment of the present invention
  • FIG8A shows how the transmittance of the target nanostructure No. 2 provided by an embodiment of the present invention varies with the incident angle
  • FIG8B shows the variation of the phase of the target nanostructure No. 2 with the incident angle provided by an embodiment of the present invention
  • FIG9 is a comparison diagram of the first average transmittance before and after replacement provided by an embodiment of the present invention.
  • FIG10 is a schematic diagram showing the structure of a metasurface design device provided by an embodiment of the present invention.
  • FIG11 shows a schematic diagram of the structure of an electronic device for executing a method for designing a metasurface according to an embodiment of the present invention.
  • the resonant mode of the resonant response is a kind of electric field distribution, which is related to the shape of the nanostructure in addition to the incident angle of the light.
  • the resonant response may no longer exist at the same incident angle. Therefore, the embodiment of the present invention can design a metasurface that still has high performance at large angles of incidence by replacing nanostructures of different shapes.
  • FIG1 shows a flow chart of a method for designing a metasurface provided by an embodiment of the present invention. As shown in FIG1 , the method includes:
  • Step 101 determining n first nanostructures, where different first nanostructures have different modulation phases for main incident light; the main incident light is incident light at a main incident angle, and n ⁇ 2.
  • the embodiment of the present invention when designing a metasurface, it is necessary to first determine nanostructures with different modulation functions, that is, different nanostructures have different modulation phases.
  • the embodiment of the present invention refers to the initially selected nanostructure as the first nanostructure.
  • all the first nanostructures may have the same shape.
  • shape may refer to the three-dimensional shape of the nanostructure, including cylindrical, square cylindrical, rectangular cylindrical, circular cylindrical, etc.; and, the "shape” is only used to characterize the appearance characteristics of the nanostructure, and does not limit the size of the nanostructure; for example, two nanostructures are both cylindrical, even if the sizes of the two are different (for example, different heights, different radii, etc.), the two are nanostructures with the same shape.
  • the modulation phase when the main incident light is incident on the nanostructure is used as a reference to select nanostructures with different modulation phases;
  • the main incident light is incident light at a certain main incident angle, and the main incident angle can be preset, and different nanostructures can be based on the main incident angle.
  • main incident light light incident on the nanostructure at a main incident angle
  • the main incident light does not specifically refer to a single light ray.
  • the incident angle of the light ray is the main incident angle, the light ray can be used as the main incident light.
  • Step 102 cyclically performing an update operation on a nanostructure set including n target nanostructures until all target nanostructures in the nanostructure set meet the wide-angle imaging requirement; the initial target nanostructure is the corresponding first nanostructure;
  • the "update operation" in the above step 102 includes the following steps 1021-1022.
  • Step 1021 Obtain performance information of each target nanostructure, including the performance information at different incident angles.
  • the performance parameters of the target nanostructure under light include transmittance and/or modulation phase; the performance information of the target nanostructure is used to determine whether the target nanostructure meets the wide-angle imaging requirements.
  • Step 1022 In the case where there is a target nanostructure that does not meet the wide-angle imaging requirement, a new second nanostructure is selected, and the target nanostructure that does not meet the wide-angle imaging requirement is replaced by the second nanostructure to generate a new nanostructure set; the second nanostructure and the target nanostructure that does not meet the wide-angle imaging requirement have the same modulation phase for the main incident light, and the second nanostructure and the target nanostructure that does not meet the wide-angle imaging requirement have different shapes.
  • the embodiment of the present invention cyclically updates the nanostructure so that all the nanostructures finally obtained meet the requirements.
  • the embodiment of the present invention refers to a set consisting of n nanostructures as a nanostructure set, and updates the nanostructure set; since the nanostructure will be replaced during the update process, in order to be able to distinguish it from the initial first nanostructure, the embodiment of the present invention refers to the nanostructure in the nanostructure set as a "target nanostructure".
  • the nanostructure set is composed of n first nanostructures, that is, each first nanostructure is used as a target nanostructure, forming an initial nanostructure set with n target nanostructures, and each target nanostructure has a different modulation phase for the main incident light.
  • the nanostructure set is updated cyclically.
  • the updating of the nanostructure set is achieved by cyclically executing the updating operation; wherein, by judging whether the target nanostructure meets the wide-angle imaging requirement, it is determined whether the target nanostructure needs to be replaced, and the updating of the nanostructure set is achieved by replacing the target nanostructure that does not meet the wide-angle imaging requirement.
  • the performance information of the target nanostructure is used to judge whether the target nanostructure meets the wide-angle imaging requirement.
  • the wide-angle imaging requirement refers to the requirement that imaging can be achieved within a wide-angle range
  • the "wide-angle" refers to a certain range of incident angles, and the range of the incident angle is determined based on the actual situation.
  • the range corresponding to the wide angle can be 0 to 30°, 20° to 60°, etc.
  • the range corresponding to the wide angle includes the main incident angle; in order for the target nanostructure to meet the wide-angle imaging requirement, the target nanostructure needs to have a good and stable modulation effect on incident light at multiple incident angles.
  • the performance information of each target nanostructure includes the performance parameters of the target nanostructure under incident light at different incident angles, and the performance parameters include transmittance and/or modulation phase.
  • the performance parameters include transmittance and modulation phase.
  • the performance information of the target nanostructure can be determined by analyzing the transmittance and modulation phase of the target nanostructure after the incident light at different incident angles is incident on the target nanostructure; for example, the performance parameters can be specifically expressed as: the relationship between transmittance and incident angle, and the relationship between modulation phase and incident angle.
  • the performance information can represent the modulation effect of the target nanostructure on incident light at different incident angles, and based on the performance information, it can be determined whether the corresponding target nanostructure meets the wide-angle imaging requirements.
  • the higher the transmittance of the target nanostructure the smaller the change in the modulation phase, and the easier it is to meet the wide-angle imaging requirements.
  • the target nanostructure with poor performance parameters is replaced, that is, the target nanostructure that does not meet the wide-angle imaging requirements is replaced.
  • the modulation phase of the main incident light is selected.
  • the newly selected nanostructure is referred to as the second nanostructure in the embodiment of the present invention. For example, if the modulation phase of the target nanostructure with poor performance parameters to the main incident light is ⁇ /2, then the modulation phase of the second nanostructure to the main incident light is also ⁇ /2.
  • the modulation phases of the two to the main incident light are the same, and the nanostructure may be used as the second nanostructure, and the modulation phases of the two are not required to be exactly the same.
  • the selected second nanostructure has a different shape from the target nanostructure with poor performance parameters.
  • the target nanostructure with poor performance parameters is cylindrical
  • nanostructures of other shapes such as square columns, cross columns, etc.
  • the modulation effect of nanostructures of different shapes may also be affected by the polarization state of the incident light.
  • Nanostructures of certain shapes are insensitive to polarization, that is, polarization is irrelevant, such as nanostructures of cylindrical, square columns, cross columns, and square columns with round holes; while nanostructures of certain shapes are sensitive to polarization, that is, polarization is relevant, such as nanostructures of elliptical columns, rectangular columns, and hexagonal prisms.
  • polarization-related nanostructures can be replaced with each other, and polarization-independent nanostructures can also be replaced with each other.
  • the original first nanostructure and any reselected second nanostructure are both polarization-related structures; or, the original first nanostructure and any reselected second nanostructure are both polarization-independent structures.
  • the target nanostructure that does not meet the wide-angle imaging requirements is replaced with a second nanostructure of another shape to form a new nanostructure set, and then the update operation can be performed again on the new nanostructure set to achieve loop iteration, and finally obtain a nanostructure set in which all target nanostructures meet the wide-angle imaging requirements. If the n target nanostructures all meet the wide-angle imaging requirements, as shown in the above step 102, the loop can be stopped at this time, that is, the update operation is no longer performed, and the n target nanostructures determined at this time are nanostructures that meet the requirements, and can be used to design and manufacture a metasurface.
  • the "new second nanostructure” may refer to: the second nanostructure is new only compared to the target nanostructure with poorer performance parameters; for example, compared to other second nanostructures that have been used before, the second nanostructure at this time may be a nanostructure with different sizes but the same shape.
  • the selected n nanostructures need to be of the same height, and under the constraint of the height, the phases modulated by nanostructures of different sizes (such as radius) are generally different, and the nanostructure that modulates a certain phase has only one size, so it is best to replace the second nanostructure by changing the shape at this time; accordingly, the second nanostructure has a different shape from the first nanostructure that has the same modulation phase for the main incident light and the other second nanostructures that have been selected that have the same modulation phase for the main incident light.
  • a cylindrical nanostructure is selected in the first round of update operation (i.e., the corresponding first nanostructure is cylindrical), which does not meet the requirements.
  • a cross-cylindrical nanostructure can be selected as the second nanostructure; during the second round of update operation, if the cross-cylindrical nanostructure still does not meet the requirements, it is necessary to select a nanostructure that is neither cylindrical nor cross-cylindrical, such as a square-cylindrical nanostructure, so that the shape of the currently selected second nanostructure is different from any previous nanostructure (including the initial first nanostructure and other second nanostructures selected in previous rounds).
  • Step 103 Design a metasurface based on the nanostructure set.
  • a metasurface can be designed based on these target nanostructures. For example, according to the function that the metasurface needs to achieve, the phase distribution of the metasurface can be determined.
  • the phase distribution can represent the phase value at the position (x, y); based on the phase distribution, it is possible to determine which target nanostructure is needed at any position of the metasurface, thereby designing the metasurface.
  • the metasurface obtained in step 103 is essentially a metasurface model, which includes the structural parameters (such as radius, height, etc.) of the nanostructures at different positions of the metasurface, and the actual required metasurface needs to be obtained based on the corresponding manufacturing process (such as photolithography process) later.
  • the modulation phase of the nanostructures required for designing the metasurface should be able to cover 0 to 2 ⁇ .
  • a part of the nanostructures covering 0 to 2 ⁇ can be selected as the n first nanostructures; or, in order to improve the design efficiency, all the nanostructures covering 0 to 2 ⁇ can be selected as the n first nanostructures, that is, the phase modulated by the n first nanostructures can cover 0 to 2 ⁇ .
  • the embodiment of the present invention takes the modulation phase of the main incident light as a reference, and the modulation phase of the main incident light by the n first nanostructures can at least cover 0 to 2 ⁇ ; and, in order to ensure the overall performance effect of the metasurface, a larger n value can be selected, for example, n ⁇ 4 or n ⁇ 6, or n ⁇ 8.
  • the "capable of covering 0 to 2 ⁇ " in the embodiments of the present invention means that it can relatively cover 0 to 2 ⁇ within the allowable error range. For example, for n nanostructures with relatively uniform modulation phase distribution, if the difference between the maximum phase and the minimum phase is close to 2 ⁇ , as long as n is large enough, it can be considered that the modulation phase of these n nanostructures can cover 0 to 2 ⁇ .
  • n 8
  • the modulation phases of the 8 nanostructures to the main incident light are respectively It can be considered that the modulation phase of the main incident light by these 8 nanostructures can cover 0 to 2 ⁇ , and these 8 nanostructures can be used as the first nanostructure.
  • the multiple nanostructures can cover 0 to 2 ⁇ , which means that the span corresponding to the phases of the multiple nanostructures can reach 2 ⁇ , and it does not limit the phases of the nanostructures to [0,2 ⁇ ].
  • the phases of these nanostructures are based on the relative phases of one of the nanostructures. For example, except for the first nanostructure, the phases of the remaining n-1 nanostructures are determined based on the phase of the first nanostructure.
  • the phase of the first nanostructure can be 0 or any other arbitrary value.
  • the phases of the other n-1 nanostructures increase (or decrease) in sequence to obtain n nanostructures that can cover 0 to 2 ⁇ .
  • the modulation phases of the above-mentioned 8 nanostructures that can cover 0 to 2 ⁇ for the main incident light are: Should can be any value; the phase of these 8 nanostructures can be any value, but the phase difference between two adjacent nanostructures is always
  • the modulation phases of the main incident light by the eight nanostructures are For example bright.
  • the metasurface design method takes the modulation phase of the main incident light as a reference, selects n nanostructures (such as the first nanostructure) with different modulation phases, and determines whether the selected nanostructure meets the wide-angle imaging requirement by analyzing its performance parameters under incident light at different incident angles, and replaces the nanostructure that does not meet the wide-angle imaging requirement with a nanostructure of other shapes to achieve an update, so that a nanostructure with a smaller resonant response can be found, and then the updated n nanostructures are used to design a metasurface.
  • the designed metasurface has a relatively stable modulation effect on incident light at different incident angles, has good overall performance, can be suitable for wide-angle imaging scenarios, and can improve the wide-angle imaging quality.
  • the wide-angle imaging requirements may also be divided into multiple items, such as wide-angle imaging transmittance requirements, wide-angle imaging phase requirements, etc.
  • the performance parameters include transmittance
  • the wide-angle imaging requirements include wide-angle imaging transmittance requirements.
  • the greater the transmittance of the target nanostructure under incident light at different incident angles the more it can meet the wide-angle imaging transmittance requirements. Accordingly, if the transmittance of the target nanostructure is smaller, it is more likely that the wide-angle imaging requirements will not be met.
  • the embodiment of the present invention uses the average transmittance of multiple target nanostructures as a whole to determine whether the wide-angle imaging transmittance requirement is met.
  • the update operation also includes the following steps A1-A2:
  • Step A1 determining a first average transmittance corresponding to each incident angle, where the first average transmittance is a weighted average of transmittances of multiple target nanostructures under incident light of the incident angle.
  • the performance information of each target nanostructure when the performance parameter includes transmittance, includes transmittance corresponding to multiple incident angles, that is, the transmittance of the target nanostructure under incident light at multiple incident angles.
  • the embodiment of the present invention performs weighted averaging on the transmittances of multiple different target nanostructures at the same incident angle to determine the average transmittance corresponding to the incident angle, that is, the first average transmittance; by performing corresponding weighted averaging on the performance information corresponding to each incident angle, the first average transmittance corresponding to each incident angle can be obtained.
  • the first average transmittance can represent the average transmittance of multiple target nanostructures to light incident at the incident angle.
  • step A1 of "determining a first average transmittance corresponding to each incident angle" includes the following steps A11.
  • Step A11 Determine the weight of each target nanostructure, and perform weighted processing on the transmittance of multiple target nanostructures under incident light of the incident angle according to the weight to obtain a first average transmittance corresponding to the incident angle.
  • the weights of different target nanostructures are the same, or the weight of the target nanostructure is positively correlated with the number of nanostructures in the metasurface that correspond to the same modulation phase as the target nanostructure.
  • w i represents the weight of the i-th target nanostructure
  • ti ,j represents the transmittance of the i-th target nanostructure under the incident light at the j-th incident angle
  • the first average transmittance corresponding to the jth incident angle In general, To achieve weighted average, the sum of all weights is 1, that is
  • the weight of the corresponding target nanostructure may be set based on the number of nanostructures corresponding to each modulation phase required by the metasurface, and the two are positively correlated, for example, they are in a positive proportional relationship. Determining the weight of the corresponding target nanostructure based on the number of each nanostructure in the metasurface can make the designed metasurface have better performance.
  • the first average transmittance corresponding to the j-th incident angle can be determined based on the above formula (1):
  • Step A2 when at least one first average transmittance is lower than a first preset transmittance threshold, determining that at least one target nanostructure does not meet the wide-angle imaging transmittance requirement.
  • the first average transmittance represents the overall performance of the entire nanostructure set. If the first average transmittance corresponding to one or more incident angles is lower than the first preset transmittance threshold, it means that the overall performance of the nanostructure set does not meet the requirements, and at least one target nanostructure in the nanostructure set does not meet the wide-angle imaging transmittance requirements, that is, there is a target nanostructure that does not meet the wide-angle imaging requirements, and it is necessary to perform the above step 1022.
  • the first average transmittance corresponding to all incident angles is not lower than (greater than or equal to) the first preset transmittance threshold, it means that the nanostructure set meets the required requirements, and it can be considered that all target nanostructures in the nanostructure set meet the wide-angle imaging transmittance requirements.
  • the transmittance requirement for the main incident angle can be set higher.
  • a second preset transmittance threshold is set that is larger than the first preset transmittance threshold, and the first average transmittance corresponding to the main incident angle is judged. If the first average transmittance corresponding to the main incident angle is lower than the second preset transmittance threshold, the nanostructure set is also considered to be unsatisfactory.
  • the first preset transmittance threshold can be 0.8
  • the second preset transmittance threshold can be 0.9.
  • Step A21 The target nanostructure with the lowest transmittance or the lowest second average transmittance is regarded as the target nanostructure that does not meet the wide-angle imaging transmittance requirement; the second average transmittance is the average transmittance of the target nanostructure under incident light at multiple incident angles.
  • a target nanostructure if a target nanostructure has the lowest transmittance compared to other target nanostructures, it can be considered that the target nanostructure does not meet the wide-angle imaging transmittance requirement.
  • the average transmittance of each target nanostructure itself that is, the second average transmittance, can be determined. If a target nanostructure has the lowest second average transmittance, it can be considered that the target nanostructure does not meet the wide-angle imaging transmittance requirement.
  • the average value of the transmittance of the target nanostructure under incident light of multiple incident angles is taken as the second average transmittance of the target nanostructure.
  • the second average transmittance of the i-th target nanostructure is satisfy:
  • m represents the number of types of incident angles.
  • the target nanostructure corresponding to the lowest transmittance or the lowest second average transmittance can be used as the target nanostructure that does not meet the wide-angle imaging transmittance requirement; or, further, other target nanostructures with lower transmittance or lower second average transmittance (for example, the second lowest) can also be used as target nanostructures that do not meet the wide-angle imaging transmittance requirement, and the embodiments of the present invention are not limited to this.
  • the above updating operation also includes steps A3-A4:
  • Step A3 Determine whether the transmission parameter of each target nanostructure is lower than a third preset transmittance threshold; the transmission parameter of the target nanostructure includes: the minimum value of the transmittance of the target nanostructure, or the second average transmittance of the target nanostructure; the second average transmittance is the average value of the transmittance of the target nanostructure under incident light at multiple incident angles.
  • Step A4 In the case where there are target nanostructures whose transmission parameters are lower than the third preset transmittance threshold, the target nanostructures having the lowest transmission parameters are regarded as target nanostructures that do not meet the wide-angle imaging transmittance requirement.
  • the minimum value of the transmittance of a certain target nanostructure can be determined, and each target nanostructure corresponds to a minimum value of the transmittance (different from the aforementioned minimum transmittance, the minimum transmittance is the minimum value of the transmittance of all target nanostructures), or, similar to the above step A21, the second average transmittance of the target nanostructure is determined, and the minimum value of the transmittance or the second average transmittance is used as the transmission parameter of the corresponding target nanostructure.
  • the third preset transmittance threshold is smaller than the first preset transmittance threshold.
  • the transmission parameter of at least one target nanostructure is lower than the third preset transmittance threshold
  • the transmission parameter of at least one target nanostructure is lower than the third preset transmittance threshold
  • at least one target nanostructure does not meet the wide-angle imaging transmittance requirement.
  • only the target nanostructure with the lowest transmission parameter that is, the lowest transmittance or the lowest second average transmittance
  • all target nanostructures with transmission parameters lower than the third preset transmittance threshold are used as target nanostructures that do not meet the wide-angle imaging transmittance requirement, which can be determined based on actual conditions.
  • the wide-angle imaging requirement includes the wide-angle imaging phase requirement accordingly; the smaller the phase gradient of the target nanostructure, the more it can meet the wide-angle imaging phase requirement.
  • the phase gradient of the target nanostructure is used to indicate the degree of change in the modulation phase of the target nanostructure.
  • the greater the degree of change in the modulation phase of the target nanostructure the more likely it is that the modulation phase of the target nanostructure has a mutation, and the greater the difference between the modulation phase of the target nanostructure and the modulation phase of the main incident light, the more difficult it is for the target nanostructure to meet the wide-angle imaging phase requirement.
  • the above update operation also includes the following steps B1-B2.
  • Step B1 Determine the phase gradient of each target nanostructure, where the phase gradient of the target nanostructure includes: the degree of change of the modulation phase difference between the target nanostructure and other adjacent target nanostructures as the incident angle changes, and/or the degree of change of the modulation phase of the target nanostructure as the incident angle changes.
  • the phase gradient of the target nanostructure is represented by the degree of change of the modulation phase with the incident angle.
  • the degree of change of the modulation phase of the target nanostructure itself with the incident angle can be used as the phase gradient of the target nanostructure; for example, the phase gradient of the target nanostructure satisfies the following formula (2) or formula (3):
  • the degree of change of the modulation phase difference between adjacent target nanostructures with the change of the incident angle is taken as the phase gradient of a certain target nanostructure.
  • two target nanostructures are adjacent, which means that the modulation phase magnitudes of the two target nanostructures to the main incident light are adjacent.
  • the i-th target nanostructure is adjacent to the i-1-th and i+1-th target nanostructures.
  • the i-th target nanostructure its corresponding phase gradient at the j-th incident angle is Spend It can be expressed as the following formula (4) or formula (5):
  • the modulation phases of the two adjacent target nanostructures on the left and right may be combined.
  • the phase gradient of the target nanostructure satisfies the following formula (6):
  • the modulation phases of the n target nanostructures to the main incident light can just cover 0 to 2 ⁇ , since the modulation phase of the nanostructure is based on a period of 2 ⁇ , for example, 0 is essentially the same as 2 ⁇ , 4 ⁇ , etc., therefore, the first target nanostructure and the nth target nanostructure are also adjacent; for example,
  • Step B2 when the phase gradient of the target nanostructure is higher than the corresponding preset gradient threshold, determining that the target nanostructure with the phase gradient higher than the preset gradient threshold does not meet the wide-angle imaging phase requirement.
  • phase gradients of the target nanostructure there are two phase gradients of the target nanostructure, and a corresponding preset gradient threshold can be set for each phase gradient; in actual application, only one of the phase gradients can be determined.
  • a corresponding preset gradient threshold can be set for each phase gradient; in actual application, only one of the phase gradients can be determined.
  • the target nanostructure does not meet the wide-angle imaging phase requirement; accordingly, if both phase gradients of the target nanostructure are lower than the corresponding preset gradient threshold, it can be considered that the target nanostructure meets the wide-angle imaging phase requirement.
  • the phase gradient of the target nanostructure can be directly compared with the preset gradient threshold.
  • indirect comparison can be achieved by other means.
  • the above-mentioned updating operation can also include steps B3-B4.
  • Step B3 Determine the change ratio between the phase gradient of the target nanostructure at the jth incident angle and the phase gradient of the target nanostructure at the main incident angle, and the change ratio satisfies the following formula (7):
  • Step B4 when the change ratio exceeds a preset ratio, determining that the phase gradient of the target nanostructure is higher than a corresponding preset gradient threshold.
  • the phase gradient of the target nanostructure determined in the above step B1 includes phase gradients corresponding to multiple incident angles, which also includes a phase gradient corresponding to the main incident angle.
  • the phase change at the main incident angle is not large, that is, the phase gradient is small.
  • the embodiment of the present invention uses the phase gradient corresponding to the main incident angle as a reference and uses the change ratio of the phase gradient to determine whether the phase gradient of the target nanostructure at other incident angles meets the requirements.
  • its phase gradient at the main incident angle is Its phase gradient at other j-th incident angles is Based on the above formula (7), the corresponding change ratio Ri ,j can be determined.
  • the change ratio Ri ,j can represent the percentage change of the phase gradient of the target nanostructure relative to the main incident angle.
  • the smaller the change ratio Ri ,j the smaller the change of the phase gradient of the i-th target nanostructure. The closer it is, the more likely it is to meet the wide-angle imaging phase requirement; on the contrary, if the change ratio Ri,j exceeds the preset ratio, it can be determined that the phase gradient of the i-th target nanostructure is higher than the corresponding preset gradient threshold (in this case, the preset gradient threshold is equivalent to the phase gradient based on the phase gradient
  • the predetermined ratio may be 10%.
  • the wide-angle imaging requirement includes a wide-angle imaging transmittance requirement and a wide-angle imaging phase requirement
  • whether the target nanostructure meets the wide-angle imaging requirement is determined based on whether the target nanostructure meets the wide-angle imaging transmittance requirement and the wide-angle imaging phase requirement; wherein, the target nanostructure meeting the wide-angle imaging transmittance requirement is a necessary condition for meeting the wide-angle imaging requirement, and the target nanostructure meeting the wide-angle imaging phase requirement is also a necessary condition for meeting the wide-angle imaging requirement.
  • the target nanostructure does not meet the wide-angle imaging transmittance requirement or does not meet the wide-angle imaging phase requirement, it can be considered that the target nanostructure does not meet the wide-angle imaging requirement; if the target nanostructure meets both the wide-angle imaging transmittance requirement and the wide-angle imaging phase requirement, it can be considered that the target nanostructure meets the wide-angle imaging requirement.
  • the embodiment of the present invention may predetermine the performance information of the nanostructure, and when the performance information of the corresponding target nanostructure needs to be obtained in step 1021, the corresponding performance information may be directly queried or called.
  • the method before the above step 102 of "cyclically executing the update operation on the nanostructure set including n target nanostructures", the method further includes:
  • Step C1 Performing performance analysis on a plurality of nanostructures of different shapes to determine performance information of each nanostructure.
  • the performance information of a large number of nanostructures can be determined in advance, and then a corresponding database can be established for subsequent use.
  • the database can also be used to preliminarily exclude nanostructures that do not meet the requirements, such as excluding nanostructures with too low transmittance or too large phase gradient, which can improve the efficiency of subsequent update operations and more quickly determine a set of nanostructures that meet the wide-angle imaging requirements.
  • an implementation of the above step of “performing performance analysis on a plurality of nanostructures of different shapes” can refer to the following steps C11-C12.
  • Step C11 construct a test metasurface corresponding to the nanostructure using multiple identical nanostructures, and The incident light is directed toward the test metasurface.
  • a hypersurface composed entirely of the nanostructure is constructed, i.e., a test hypersurface, and the nanostructures possessed by the test hypersurface are all the nanostructures to be analyzed.
  • the test hypersurface is generally a simulated hypersurface, which can be formed by simulation testing and other methods, and test analysis under different incident angles can be achieved.
  • Step C12 taking the performance parameters of the test metasurface under incident light at different incident angles as the corresponding performance parameters of the nanostructure.
  • the test metasurface has the same performance parameters as the corresponding nanostructure, so the performance parameters of the corresponding nanostructure can be obtained by determining the performance parameters of the test metasurface.
  • a certain point can be used as a reference point to determine the performance parameters of the reference point.
  • the above step C12 may include: determining the performance parameters at a reference point on the light-emitting side of the test metasurface, and using the performance parameters at the reference point as the performance parameters of the nanostructure; the reference point corresponds to the center of the test metasurface, and the distance between the reference point and the center of the test metasurface is less than a preset distance.
  • a reference point is selected on the light-emitting side of the test metasurface, and the performance parameters of the nanostructure are determined by detecting the performance parameters at the reference point.
  • the reference point can be located at a position corresponding to the center of the test metasurface, and the distance from the test metasurface is relatively close, for example, a distance of 1um.
  • the method for designing the metasurface includes steps 201 - 209 .
  • Step 201 Perform performance analysis on a plurality of nanostructures of different shapes to determine performance information of each nanostructure.
  • the performance analysis can be performed on nanostructures of various shapes and sizes (for example, different heights, radii, periods, etc.) such as cylindrical, square, and cross-shaped, to determine the transmittance and modulation phase corresponding to each nanostructure at different incident angles.
  • the main incident angle in the embodiment of the present invention is 0°, that is, the main incident light is the normal incident light, and the angle range of the performance analysis is 0 to 30°; accordingly, the performance information includes the transmittance and modulation phase corresponding to 0 to 30°.
  • Step 202 Determine eight first nanostructures, where different first nanostructures have different modulation phases for the main incident light.
  • the embodiment of the present invention sorts the eight first nanostructures according to the magnitude of the modulated phases: the first nanostructure 1 represents the first nanostructure with a serial number of 1, and its modulation phase to the main incident light is 0; the first nanostructure 2 represents the first nanostructure with a serial number of 2, and its modulation phase to the main incident light is whil, the first nanostructure 8 represents the first nanostructure with serial number 8, and its modulation phases for the main incident light are respectively
  • Step 203 taking the eight first nanostructures as corresponding target nanostructures to generate an initial nanostructure set.
  • target nanostructure 1 represents the target nanostructure with serial number 1, and its modulation phase for the main incident light is 0;
  • target nanostructure 2 represents the target nanostructure with serial number 2, and its modulation phase for the main incident light is ...
  • Target nanostructure 8 represents the target nanostructure with serial number 8, and its modulation phases for the main incident light are respectively
  • Step 204 Acquire performance information of eight target nanostructures.
  • the performance information of the 8 target nanostructures can be obtained based on the data query determined in the above step 201; or, if the 8 target nanostructures include a newly replaced target nanostructure, then only the performance information of the newly replaced target nanostructure needs to be obtained.
  • the designed metasurface uses silicon (Si) as the material of the nanostructure and silicon dioxide (SiO 2 ) as the substrate of the nanostructure; and the height and period of the nanostructure are preset, and the phase modulation effect of the nanostructure is changed by changing the cross-sectional size (such as radius, diameter, etc.) of the nanostructure, that is, nanostructures with different cross-sectional sizes have different modulation phases.
  • the height of the nanostructure in the metasurface is 600nm
  • the period is 490nm
  • its working wavelength is 850nm.
  • a cylindrical nanostructure is selected as the first nanostructure.
  • the initial 8 target nanostructures are all cylindrical, and the schematic diagram of the cylindrical target nanostructure can be seen in Figure 3; and the performance information of the 8 target nanostructures can be seen in Figures 4A and 4B, and 1 to 8 in Figures 4A and 4B represent the serial numbers of the 8 target nanostructures.
  • Figure 4A represents the transmittance of the 8 cylindrical target nanostructures at different incident angles
  • Figure 4B represents the phase of the 8 cylindrical target nanostructures at different incident angles (i.e., the above-mentioned modulation phase, in rad). It can be seen from Figures 4A and 4B that the transmittance of target nanostructures 2, 3, 4, and 5 at some incident angles is small, and the phase gradient of target nanostructures 3, 4, and 5 is large.
  • Fig. 5A and Fig. 5B show the transmittance and phase of different target nanostructures at incident angles of 0° and 30°.
  • the eight target nanostructures can basically achieve full coverage of the phase from 0 to 2 ⁇ , and as shown in Fig. 5A, each target nanostructure shows a transmittance higher than 0.9 at normal incidence, as shown in Fig. 5B, when the incident angle is 30°, the transmittances of the target nanostructures numbered 3, 4, and 5 are all lower than 0.6, and even the minimum transmittance is about 0.2.
  • the super surface can only be used within a small angle range, and the optical performance will drop sharply at a large angle.
  • the poorer target nanostructures can be screened and replaced, and the specific steps can be referred to as shown below.
  • Step 205 Determine a first average transmittance corresponding to each incident angle, and determine a phase gradient of each target nanostructure.
  • Step 206 Determine whether the first average transmittance is higher than a first preset transmittance threshold and whether the phase gradient is lower than a preset gradient threshold. If so, execute step 208; otherwise, execute step 207.
  • Step 207 determine the target nanostructure that does not meet the wide-angle imaging requirement, and replace the target nanostructure that does not meet the wide-angle imaging requirement with a new second nanostructure, generate a new nanostructure set, and re-execute step 204.
  • Steps 204-207 are update operations.
  • the first average transmittance is not higher than the first preset transmittance threshold, it indicates that there is a target nanostructure that does not meet the wide-angle imaging transmittance requirement; specifically, as shown in the above step A21, the target nanostructure with the lowest transmittance or the lowest second average transmittance can be used as the target nanostructure that does not meet the wide-angle imaging transmittance requirement. If the phase gradient of the target nanostructure is not lower than the preset gradient threshold, it indicates that the target nanostructure does not meet the wide-angle imaging phase requirement.
  • the target nanostructure that does not meet the wide-angle imaging transmittance requirement and/or does not meet the wide-angle imaging phase requirement can be used as the target nanostructure that does not meet the wide-angle imaging transmittance requirement and/or does not meet the wide-angle imaging phase requirement.
  • the required target nanostructure is used as the target nanostructure that does not meet the wide-angle imaging requirement and is replaced by a new second nanostructure, which is used as a new target nanostructure, thereby generating a new nanostructure set including 8 target nanostructures.
  • the transmittance and phase of the cylindrical target nanostructure 3 do not meet the requirements, and its transmittance is low, and the phase gradient is large, so the target nanostructure 3 is a target nanostructure that does not meet the wide-angle imaging requirements; the embodiment of the present invention selects a cross-column-shaped nanostructure as the second nanostructure, and replaces the cylindrical target nanostructure 3 to form a new target nanostructure 3 and a new nanostructure set.
  • the schematic diagram of the cross-column-shaped nanostructure can be seen in Figure 6, and the schematic diagram of replacing the target nanostructure 3 to form a new nanostructure set can be seen in Figure 7.
  • the performance of the cylindrical target nanostructures 2, 3, and 4 are all relatively poor, and the three target nanostructures can be replaced at once in one update operation.
  • the cylindrical target nanostructures 2, 3, and 4 are replaced by three cross-column-shaped second nanostructures.
  • the three can replace the cylindrical target nanostructures 2, 3, and 4.
  • Table 1 shows the parameters of eight cylindrical target nanostructures when the incident angle is 30°.
  • the embodiment of the present invention also provides the variation of the transmittance and phase of the target nanostructure numbered 2 with the incident angle, which can be specifically seen in Figures 8A and 8B; wherein each figure corresponds to a cylindrical target nanostructure and a cross-column target nanostructure.
  • Figures 8A and 8B it can be seen that the transmittance of the cross-column target nanostructure 2 is The entire angle range analyzed (i.e., 0-30°) shows a high transmittance, and the phase mutation is not obvious. Therefore, in the embodiment of the present invention, by replacing the cylindrical target nanostructure with a cross-column second nanostructure, the transmittance and modulation phase performance of the new nanostructure set can be improved.
  • the next round of update operation can be performed, that is, the above step 204 can be re-executed to further determine the transmittance and phase gradient of the target nanostructure in the new nanostructure set to determine whether it meets the phase imaging requirements.
  • the three cross-cylindrical nanostructures (second nanostructures) corresponding to Table 2 replace the cylindrical target nanostructures 2, 3, and 4, and the replaced structure (including 5 cylindrical nanostructures and 3 cross-cylindrical nanostructures) can be obtained.
  • the first average transmittance of the replaced structure can be specifically shown in Figure 9; and Figure 9 shows the first average transmittance of the original full cylindrical structure (including 8 cylindrical nanostructures) by comparison, and the average transmittance of the ordinate of Figure 9 is the first average transmittance.
  • the replaced structure has a first average transmittance higher than 0.9 at normal incidence, and the transmittance at a large angle still maintains a high value higher than 0.85; it is different from the low first average transmittance when the cylindrical structure is all before replacement.
  • the replaced nanostructure set has better transmittance.
  • the phase gradient of the replaced nanostructure set can also be analyzed, which is not described in detail in this embodiment.
  • Step 208 Determine whether the current nanostructure set meets the wide-angle imaging requirement.
  • the eight target nanostructures if all the first average transmittances are higher than the first preset transmittance threshold, it can be considered that the eight target nanostructures all meet the wide-angle imaging transmittance requirement; if the phase gradient of each target nanostructure is lower than the preset gradient threshold, it can be considered that the eight target nanostructures all meet the wide-angle imaging phase requirement. At this time, it can be considered that the eight target nanostructures all meet the wide-angle imaging requirement, that is, the current nanostructure set (including the current eight target nanostructures) meets the wide-angle imaging requirement and can be used to design a metasurface.
  • Step 209 Design a metasurface based on the current set of nanostructures.
  • the metasurface design method provided in the embodiment of the present invention analyzes the optical responses (including transmittance and modulation phase) of nanostructures of different geometric shapes at different incident angles, and adopts a method of replacing the nanostructure.
  • the nanostructure with low transmittance and phase mutation can be replaced by a nanostructure of other geometric shapes with the same modulation phase of the main incident light.
  • the overall performance of the designed metasurface is improved on the basis of minimizing the changes in the preliminary design structure, and the metasurface has better transmittance and modulation phase even at large oblique incidence.
  • the above describes in detail the design method of the metasurface provided by the embodiment of the present invention.
  • the method can also be implemented by a corresponding device.
  • the following describes in detail the design device of the metasurface provided by the embodiment of the present invention.
  • FIG10 is a schematic diagram showing the structure of a design device for a metasurface provided by an embodiment of the present invention.
  • the design device for a metasurface includes:
  • An initial module 11 is used to determine n first nanostructures, where different first nanostructures have different modulation phases for main incident light; the main incident light is incident light at a main incident angle, and n ⁇ 2;
  • An updating module 12 is used to cyclically perform an updating operation on a nanostructure set including n target nanostructures until all the target nanostructures in the nanostructure set meet the wide-angle imaging requirement; the initial target nanostructure is the corresponding first nanostructure;
  • the updating module 12 includes an acquiring unit 121 and an updating unit 122;
  • the acquisition unit 121 is used to acquire performance information of each target nanostructure, wherein the performance information includes Performance parameters of the target nanostructure under incident light at different incident angles, the performance parameters including transmittance and/or modulation phase; the performance information of the target nanostructure is used to determine whether the target nanostructure meets the wide-angle imaging requirements;
  • the updating unit 122 is used to, when there is a target nanostructure that does not meet the wide-angle imaging requirement, select a new second nanostructure and replace the target nanostructure that does not meet the wide-angle imaging requirement with the second nanostructure to generate a new nanostructure set; the second nanostructure and the target nanostructure that does not meet the wide-angle imaging requirement have the same modulation phase for the main incident light, and the second nanostructure and the target nanostructure that does not meet the wide-angle imaging requirement have a different shape.
  • the wide-angle imaging requirement when the performance parameter includes transmittance, includes a wide-angle imaging transmittance requirement; the greater the transmittance of the target nanostructure under incident light at different incident angles, the more it can meet the wide-angle imaging transmittance requirement.
  • the update operation performed by the update module 12 further includes:
  • the first average transmittance is a weighted average of transmittances of a plurality of the target nanostructures under incident light at the incident angle
  • At least one of the first average transmittances is lower than a first preset transmittance threshold, it is determined that at least one target nanostructure does not meet the wide-angle imaging transmittance requirement.
  • the updating module 12 determines the first average transmittance corresponding to each incident angle, including:
  • the first average transmittance satisfies:
  • w i represents the weight of the i-th target nanostructure
  • ti ,j represents the transmittance of the i-th target nanostructure under the incident light at the j-th incident angle
  • w i represents the weight of the i-th target nanostructure
  • ti ,j represents the transmittance of the i-th target nanostructure under the incident light at the j-th incident angle
  • w i represents the weight of the i-th target nanostructure
  • ti ,j represents the transmittance of the i-th target nanostructure under the incident light at the j-th incident angle
  • the determining that at least one target nanostructure does not meet the wide-angle imaging transmittance requirement performed by the updating module 12 includes:
  • the target nanostructure with the lowest transmittance or the lowest second average transmittance is regarded as the target nanostructure that does not meet the wide-angle imaging transmittance requirement; the second average transmittance is the average transmittance of the target nanostructure under incident light of multiple incident angles.
  • the update operation performed by the update module 12 further includes:
  • the first average transmittance is not lower than a first preset transmittance threshold, and the main incident angle
  • the corresponding first average transmittance is not lower than the second preset transmittance threshold, it is determined that all the target nanostructures meet the wide-angle imaging transmittance requirement; and the second preset transmittance threshold is greater than the first preset transmittance threshold.
  • the update operation performed by the update module 12 further includes:
  • the transmission parameter of the target nanostructure includes: a minimum value of the transmittance of the target nanostructure, or a second average transmittance of the target nanostructure; the second average transmittance is an average value of the transmittance of the target nanostructure under incident light of multiple incident angles;
  • the target nanostructures having the lowest transmission parameters are regarded as target nanostructures that do not meet the wide-angle imaging transmittance requirement.
  • the wide-angle imaging requirement includes a wide-angle imaging phase requirement; the smaller the phase gradient of the target nanostructure, the more it can meet the wide-angle imaging phase requirement; wherein the phase gradient of the target nanostructure is used to indicate the degree of change in the modulation phase of the target nanostructure.
  • the update operation performed by the update module 12 further includes:
  • phase gradient of each of the target nanostructures comprising: a degree of variation of a modulation phase difference between the target nanostructure and other adjacent target nanostructures as the incident angle changes, and/or a degree of variation of a modulation phase of the target nanostructure as the incident angle changes;
  • the phase gradient of the target nanostructure is higher than the corresponding preset gradient threshold, it is determined that the target nanostructure with the phase gradient higher than the preset gradient threshold does not meet the wide-angle imaging phase requirement.
  • the update operation performed by the update module 12 further includes:
  • the device further includes an analysis module
  • the analysis module is used to perform performance analysis on a plurality of nanostructures of different shapes to determine performance information of each of the nanostructures before the update module 12 cyclically performs an update operation on the nanostructure set including the n target nanostructures.
  • the analysis module performs performance analysis on a plurality of nanostructures of different shapes, including:
  • a test metasurface corresponding to the nanostructure is formed by using a plurality of the same nanostructures, and the test metasurface is formed by using different incident angles. emitting incident light toward the test metasurface;
  • the performance parameters of the test metasurface under incident light at different incident angles are used as the corresponding performance parameters of the nanostructure.
  • the second nanostructure has a different shape from the first nanostructure having the same modulation phase for the main incident light and other previously selected second nanostructures having the same modulation phase for the main incident light.
  • the main incident angle is 0° ⁇ , where ⁇ represents an angle value within an allowable error range.
  • the modulation phases of the n first nanostructures on the main incident light can at least cover 0 to 2 ⁇ .
  • n is greater than or equal to 8.
  • both the first nanostructure and the second nanostructure are polarization-dependent structures; or both the first nanostructure and the second nanostructure are polarization-independent structures.
  • An embodiment of the present invention further provides a metasurface design device, the design device comprising: a processor, the processor being used to execute a computer program stored in a memory to implement a metasurface design method provided by any of the above method embodiments.
  • the metasurface design device includes a processor and a memory; the memory is configured to store a computer program; the processor is configured to execute the computer program so that the metasurface design device can perform the following operations:
  • n first nanostructures wherein different first nanostructures have different modulation phases for main incident light; the main incident light is incident light at a main incident angle, and n ⁇ 2;
  • the initial target nanostructure is the corresponding first nanostructure
  • the updating operation includes:
  • the performance information comprising performance parameters of the target nanostructure under incident light at different incident angles, the performance parameters comprising transmittance and/or modulation phase; the performance information of the target nanostructure is used to determine whether the target nanostructure meets the wide-angle imaging requirement;
  • a new second nanostructure is selected and the target nanostructure that does not meet the wide-angle imaging requirements is replaced by the second nanostructure to generate a new nanostructure set; the second nanostructure and the target nanostructure that does not meet the wide-angle imaging requirements have the same modulation phase for the main incident light, and the second nanostructure and the target nanostructure that does not meet the wide-angle imaging requirements have different shapes.
  • an embodiment of the present invention further provides an electronic device, including a bus, a transceiver, a memory, a processor, and a computer program stored in the memory and executable on the processor.
  • the transceiver, the memory, and the processor are respectively connected via a bus.
  • the computer program is executed by the processor, each process of the above-mentioned metasurface design method embodiment is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.
  • an embodiment of the present invention further provides an electronic device, the electronic device comprising a bus 1110 , processor 1120 , transceiver 1130 , bus interface 1140 , memory 1150 , and user interface 1160 .
  • the electronic device further includes: a computer program stored in the memory 1150 and executable on the processor 1120, and when the computer program is executed by the processor 1120, each process of the above-mentioned metasurface design method embodiment is implemented.
  • the transceiver 1130 is configured to receive and send data under the control of the processor 1120 .
  • bus architecture represented by bus 1110
  • bus 1110 may include any number of interconnected buses and bridges, and bus 1110 connects various circuits including one or more processors represented by processor 1120 and a memory represented by memory 1150.
  • Bus 1110 represents one or more of any of several types of bus structures, including a memory bus and memory controller, a peripheral bus, an Accelerate Graphical Port (AGP), a processor, or a local bus using any of a variety of bus architectures.
  • bus architectures include: Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA), Peripheral Component Interconnect (PCI) bus.
  • the processor 1120 may be an integrated circuit chip having signal processing capabilities. In the implementation process, each step of the above method embodiment may be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software.
  • the above processors include: a general processor, a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a complex programmable logic device (CPLD), a programmable logic array (PLA), a microcontroller unit (MCU) or other programmable logic devices, discrete gates, transistor logic devices, discrete hardware components.
  • the methods, steps and logic block diagrams disclosed in the embodiments of the present invention may be implemented or executed.
  • the processor may be a single-core processor or a multi-core processor, and the processor may be integrated into a single chip or located on multiple different chips.
  • Processor 1120 can be a microprocessor or any conventional processor.
  • the method steps disclosed in the embodiment of the present invention can be directly executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor.
  • the software module can be located in a readable storage medium known in the art, such as a random access memory (RAM), a flash memory (Flash Memory), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a register, etc.
  • RAM random access memory
  • Flash Memory Flash Memory
  • ROM read-only memory
  • PROM programmable read-only memory
  • EPROM erasable programmable read-only memory
  • register etc.
  • the readable storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.
  • the bus 1110 may also connect various other circuits such as peripheral devices, voltage regulators or power management circuits, and the bus interface 1140 provides an interface between the bus 1110 and the transceiver 1130, which are well known in the art. Therefore, the embodiment of the present invention will not be further described.
  • the transceiver 1130 may be one element or multiple elements, such as multiple receivers and transmitters, and provides a unit for communicating with various other devices on a transmission medium. For example, the transceiver 1130 receives external data from other devices, and the transceiver 1130 is used to send data processed by the processor 1120 to other devices.
  • a user interface 1160 may be provided, such as a touch screen, a physical keyboard, a display, a mouse, a speaker, a microphone, a trackball, a joystick, or a stylus.
  • the memory 1150 may further include a memory remotely arranged relative to the processor 1120, and these remotely arranged memories may be connected to the server through a network.
  • One or more parts of the above-mentioned network may be an ad hoc network, an intranet, an extranet, a virtual private network (VPN), a local area network (LAN), a wireless local area network (WLAN), a wide area network (WAN), a wireless wide area network (WWAN), a metropolitan area network (MAN), the Internet, a public switched telephone network (PSTN), a plain old telephone service network (POTS), a cellular telephone network, a wireless network, a wireless fidelity (Wi-Fi) network, and a combination of two or more of the above-mentioned networks.
  • VPN virtual private network
  • LAN local area network
  • WLAN wireless local area network
  • WAN wide area network
  • WWAN wireless wide area network
  • MAN metropolitan area network
  • PSTN public switched telephone network
  • POTS plain old telephone service network
  • the cellular telephone network and the wireless network may be a Global Mobile Communications (GSM) system, a Code Division Multiple Access (CDMA) system, a Worldwide Interoperability for Microwave Access (WiMAX) system, a General Packet Radio Service (GPRS) system, a Wideband Code Division Multiple Access (WCDMA) system, a Long Term Evolution (LTE) system, a LTE Frequency Division Duplex (FDD) system, a LTE Time Division Duplex (TDD) system, an Advanced Long Term Evolution (LTE-A) system, a Universal Mobile Telecommunications (UMTS) system, an Enhanced Mobile Broadband (eMBB) system, a Massive Machine Type of Communication (mMTC) system, an Ultra Reliable Low Latency Communications (uRLLC) system, and the like.
  • GSM Global Mobile Communications
  • CDMA Code Division Multiple Access
  • WiMAX Worldwide Interoperability for Microwave Access
  • GPRS General Packet Radio Service
  • WCDMA Wideband Code Division Multiple Access
  • LTE Long
  • the memory 1150 in the embodiment of the present invention may be a volatile memory or a non-volatile memory, or may include both a volatile memory and a non-volatile memory.
  • the non-volatile memory includes: a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory.
  • Volatile memory includes: Random Access Memory (RAM), which is used as an external cache.
  • RAM Random Access Memory
  • DRAM Dynamic RAM
  • SDRAM Synchronous DRAM
  • DDRSDRAM Double Data Rate SDRAM
  • ESDRAM Enhanced SDRAM
  • SLDRAM Synchronous DRAM
  • DRRAM Direct Rambus RAM
  • the memory 1150 of the electronic device described in the embodiment of the present invention includes but is not limited to the above and any other suitable types of memory.
  • the memory 1150 stores the following elements of the operating system 1151 and the application program 1152: executable modules, data structures, or subsets thereof, or extended sets thereof.
  • the operating system 1151 includes various system programs, such as a framework layer, a core library layer, a driver layer, etc., which are used to implement various basic services and process hardware-based tasks.
  • the application 1152 includes various application programs, such as a media player (Media Player) and a browser (Browser), which are used to implement various application services.
  • the program that implements the method of the embodiment of the present invention may be included in the application 1152.
  • the application 1152 includes applets, objects, components, logic, data structures, and other computer system executable instructions that perform specific tasks or implement specific abstract data types.
  • an embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored.
  • a computer program is executed by a processor, each process of the above-mentioned metasurface design method embodiment is implemented, and the corresponding The same technical effects are achieved, and will not be described here to avoid repetition.
  • Computer readable storage media include: permanent and non-permanent, removable and non-removable media, which are tangible devices that can retain and store instructions for use by instruction execution devices.
  • Computer readable storage media include: electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, and any suitable combination of the above.
  • Computer readable storage media include: phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassette storage, magnetic tape disk storage or other magnetic storage devices, memory sticks, mechanical encoding devices (such as punched cards or raised structures in grooves with instructions recorded thereon) or any other non-transmission medium that can be used to store information that can be accessed by a computing device.
  • PRAM phase change memory
  • SRAM static random access memory
  • DRAM dynamic random access memory
  • RAM random access memory
  • ROM read-only memory
  • NVRAM non-volatile random access memory
  • EEPROM electrically erasable programmable read-only memory
  • flash memory or other memory technology
  • CD-ROM compact disk
  • computer-readable storage media do not include temporary signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (such as light pulses passing through fiber optic cables), or electrical signals transmitted through wires.
  • the disclosed devices, electronic devices and methods can be implemented in other ways.
  • the device embodiments described above are only schematic.
  • the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.
  • the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.
  • the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one location or distributed on multiple network units. Some or all of the units may be selected according to actual needs to solve the problem to be solved by the embodiments of the present invention.
  • each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.
  • the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium.
  • the technical solution of the embodiment of the present invention is essentially or part of the contribution to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (including: a personal computer, a server, a data center or other network device) to perform all or part of the steps of the method described in each embodiment of the present invention.
  • the above-mentioned storage medium includes various media that can store program codes as listed above.
  • the embodiments of the present invention can be implemented as methods, devices, electronic devices and computer-readable storage media. Therefore, the embodiments of the present invention can be specifically implemented in the following forms: complete hardware, complete software (including firmware, resident software, microcode, etc.), a combination of hardware and software.
  • the embodiments of the present invention can also be implemented in the form of a computer program product in one or more computer-readable storage media, and the computer-readable storage medium contains computer program code.
  • Computer-readable storage medium may adopt any combination of one or more computer-readable storage media.
  • Computer-readable storage media include: electrical, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or devices, or any combination of the above. More specific examples of computer-readable storage media include: portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM), flash memory (Flash Memory), optical fibers, compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices or any combination of the above.
  • a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in conjunction with an instruction execution system, device, or device.
  • the computer program code contained in the above-mentioned computer-readable storage medium can be transmitted using any appropriate medium, including: wireless, wire, optical cable, radio frequency (Radio Frequency, RF) or any suitable combination of the above.
  • any appropriate medium including: wireless, wire, optical cable, radio frequency (Radio Frequency, RF) or any suitable combination of the above.
  • the computer program code for performing the operation of the embodiments of the present invention can be written in assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, integrated circuit configuration data, or in one or more programming languages or a combination thereof, wherein the programming language includes an object-oriented programming language, such as Java, Smalltalk, C++, and also includes a conventional procedural programming language, such as C language or a similar programming language.
  • the computer program code can be executed completely on the user's computer, partially on the user's computer, as an independent software package, partially on the user's computer, partially on a remote computer, and completely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer or to an external computer through any type of network, including a local area network (LAN) or a wide area network (WAN).
  • LAN local area network
  • WAN wide area network
  • the embodiments of the present invention describe the provided methods, devices, and electronic devices through flowcharts and/or block diagrams.
  • each box in the flowchart and/or block diagram and the combination of boxes in the flowchart and/or block diagram can be implemented by computer-readable program instructions.
  • These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer or other programmable data processing device to produce a machine, and these computer-readable program instructions are executed by a computer or other programmable data processing device to produce a device that implements the functions/operations specified by the boxes in the flowchart and/or block diagram.
  • These computer-readable program instructions may also be stored in a computer-readable storage medium that enables a computer or other programmable data processing device to work in a specific manner. In this way, the instructions stored in the computer-readable storage medium produce an instruction device product including functions/operations specified in the blocks in the flowchart and/or block diagram.
  • Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device, so that a series of operational steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby enabling the instructions executed on the computer or other programmable data processing apparatus to provide a process for implementing the functions/operations specified in the blocks in the flowchart and/or block diagram.

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Abstract

本发明提供了一种超表面的设计方法、装置及电子设备，其中，该方法包括：确定n个对主入射光的调制相位不同的第一纳米结构；对包括n个目标纳米结构的纳米结构集循环执行更新操作，直至纳米结构集中所有目标纳米结构均满足广角成像要求；最初的目标纳米结构为相应的第一纳米结构；基于纳米结构集设计超表面；其中，更新操作包括：以第二纳米结构代替不满足广角成像要求的目标纳米结构，生成新的纳米结构集。通过本发明实施例提供的技术方案，将不满足广角成像要求的纳米结构替换为其他形状的纳米结构，实现更新，从而可以寻找到谐振响应较小的纳米结构，实现超表面设计，所设计的超表面整体性能较好，可以适用于广角成像的场景。

Description

一种超表面的设计方法、装置及电子设备 技术领域
本发明涉及超表面技术领域，具体而言，涉及一种超表面的设计方法、装置、电子设备及计算机可读存储介质。
背景技术
超表面的相位调控机制一般都基于正入射或小角度入射，对大角度斜入射下的光学性能的考虑较少，而在广角成像等领域则需要考虑大角度入射的光，此时超表面会出现成像质量降低的问题，其部分原因来自斜入射时部分结构单元(纳米结构)因谐振响应导致的透射率低和相位突变的问题。例如，部分硅纳米圆柱对于斜入射的光会存在谐振响应，导致透射率变化以及相位突变，最终导致所设计的超表面不适用于大角度入射的场景。
发明内容
为解决现有存在的技术问题，本发明实施例提供一种超表面的设计方法、装置、电子设备及计算机可读存储介质。
第一方面，本发明实施例提供了一种超表面的设计方法，包括：
确定n个第一纳米结构，不同的所述第一纳米结构对主入射光的调制相位不同；所述主入射光为以主入射角度入射的入射光，n≥2；
对包括n个目标纳米结构的纳米结构集循环执行更新操作，直至所述纳米结构集中所有所述目标纳米结构均满足广角成像要求；最初的所述目标纳米结构为相应的所述第一纳米结构；
基于所述纳米结构集设计超表面；
其中，所述更新操作包括：
获取每个所述目标纳米结构的性能信息，所述性能信息包括在不同入射角度的入射光下所述目标纳米结构的性能参数，所述性能参数包括透射率和/或调制相位；所述目标纳米结构的性能信息用于判断所述目标纳米结构是否满足广角成像要求；
在存在不满足广角成像要求的目标纳米结构的情况下，选取新的第二纳米结构，并以所述第二纳米结构代替所述不满足广角成像要求的目标纳米结构，生成新的纳米结构集；所述第二纳米结构与所述不满足广角成像要求的目标纳米结构对所述主入射光的调制相位相同，且所述第二纳米结构与所述不满足广角成像要求的目标纳米结构具有不同的形状。
在一种可能的实现方式中，在所述性能参数包括透射率的情况下，所述广角成像要求包括广角成像透射率要求；所述目标纳米结构在不同入射角度的入射光下的透射率越大，越能够满足所述广角成像透射率要求。
在一种可能的实现方式中，所述更新操作还包括：
确定每个所述入射角度对应的第一平均透射率，所述第一平均透射率为多个所述目标纳米结构在所述入射角度的入射光下的透射率的加权平均值；
在至少一个所述第一平均透射率低于第一预设透射率阈值的情况下，确定至少一个目标纳米结构不满足所述广角成像透射率要求。
在一种可能的实现方式中，所述确定每个所述入射角度对应的第一平均透射率，包括：
确定每个所述目标纳米结构的权重，根据所述权重对多个所述目标纳米结构在所述入 射角度的入射光下的透射率进行加权处理，得到所述入射角度对应的第一平均透射率；不同的所述目标纳米结构的权重相同，或者，所述目标纳米结构的权重与所述超表面中与所述目标纳米结构对应同一调制相位的纳米结构的数量之间为正相关关系；
所述第一平均透射率满足：
其中，wi表示第i个目标纳米结构的权重，ti,j表示第i个目标纳米结构在第j个入射角度的入射光下的透射率，表示第j个入射角度对应的第一平均透射率。
在一种可能的实现方式中，所述确定至少一个目标纳米结构不满足所述广角成像透射率要求，包括：
将具有最低透射率或具有最低第二平均透射率的目标纳米结构作为不满足所述广角成像透射率要求的目标纳米结构；所述第二平均透射率为所述目标纳米结构在多个所述入射角度的入射光下的透射率的平均值。
在一种可能的实现方式中，所述更新操作还包括：
在所有所述第一平均透射率均不低于第一预设透射率阈值的情况下，确定所有所述目标纳米结构均满足所述广角成像透射率要求；
或者，在所有所述第一平均透射率均不低于第一预设透射率阈值、且所述主入射角度对应的第一平均透射率不低于第二预设透射率阈值的情况下，确定所有所述目标纳米结构均满足所述广角成像透射率要求；所述第二预设透射率阈值大于所述第一预设透射率阈值。
在一种可能的实现方式中，所述更新操作还包括：
判断每个所述目标纳米结构的透射参数是否低于第三预设透射率阈值；所述目标纳米结构的透射参数包括：所述目标纳米结构的透射率中的最小值，或者，所述目标纳米结构的第二平均透射率；所述第二平均透射率为所述目标纳米结构在多个所述入射角度的入射光下的透射率的平均值；
在存在透射参数低于第三预设透射率阈值的目标纳米结构的情况下，将具有最低透射参数的目标纳米结构作为不满足所述广角成像透射率要求的目标纳米结构。
在一种可能的实现方式中，在所述性能参数包括调制相位的情况下，所述广角成像要求包括广角成像相位要求；所述目标纳米结构的相位梯度越小，越能够满足所述广角成像相位要求；其中，所述目标纳米结构的相位梯度用于表示所述目标纳米结构的调制相位的变化程度。
在一种可能的实现方式中，所述更新操作还包括：
确定每个所述目标纳米结构的相位梯度，所述目标纳米结构的相位梯度包括：所述目标纳米结构与相邻的其他目标纳米结构之间的调制相位之差随入射角度变化所具有的变化程度，和/或，所述目标纳米结构的调制相位随入射角度变化所具有的变化程度；
在所述目标纳米结构的相位梯度高于相应的预设梯度阈值的情况下，确定相位梯度高于预设梯度阈值的目标纳米结构不满足所述广角成像相位要求。
在一种可能的实现方式中，所述更新操作还包括：
确定所述目标纳米结构在第j个入射角度处的相位梯度与所述目标纳米结构在所述主入射角度处的相位梯度之间的变化比，且所述变化比满足：
其中，表示第i个目标纳米结构在第j个入射角度处的相位梯度，表示第i个目标纳米结构在所述主入射角度处的相位梯度，Ri,j表示第i个目标纳米结构在第j个入射角度处的变化比；
在所述变化比超过预设比值的情况下，确定所述目标纳米结构的相位梯度高于相应的预设梯度阈值。
在一种可能的实现方式中，在所述对包括n个目标纳米结构的纳米结构集循环执行更新操作之前，该方法还包括：
对多个不同形状的纳米结构进行性能分析，确定每个所述纳米结构的性能信息。
在一种可能的实现方式中，所述对多个不同形状的纳米结构进行性能分析，包括：
以多个同一所述纳米结构构成与所述纳米结构对应的测试超表面，并以不同入射角度向所述测试超表面出射入射光；
将所述测试超表面在不同入射角度的入射光下的性能参数作为所述纳米结构相应的性能参数。
在一种可能的实现方式中，所述第二纳米结构与对所述主入射光具有同一调制相位的第一纳米结构以及对所述主入射光具有同一调制相位的曾经选取的其他第二纳米结构均形状不同。
在一种可能的实现方式中，所述主入射角度为0°±Δ，Δ表示在误差允许范围内的角度值。
在一种可能的实现方式中，n个所述第一纳米结构对主入射光的调制相位至少能够覆盖0至2π。
在一种可能的实现方式中，n大于或等于8。
在一种可能的实现方式中，所述第一纳米结构与所述第二纳米结构均为偏振相关结构；或者，所述第一纳米结构与所述第二纳米结构均为偏振不相关结构。
第二方面，本发明实施例还提供了一种超表面的设计装置，包括：
初始模块，用于确定n个第一纳米结构，不同的所述第一纳米结构对主入射光的调制相位不同；所述主入射光为以主入射角度入射的入射光，n≥2；
更新模块，用于对包括n个目标纳米结构的纳米结构集循环执行更新操作，直至所述纳米结构集中所有所述目标纳米结构均满足广角成像要求；最初的所述目标纳米结构为相应的所述第一纳米结构；
设计模块，用于基于所述纳米结构集设计超表面；
其中，所述更新模块包括获取单元和更新单元；
所述获取单元用于，获取每个所述目标纳米结构的性能信息，所述性能信息包括在不同入射角度的入射光下所述目标纳米结构的性能参数，所述性能参数包括透射率和/或调制相位；所述目标纳米结构的性能信息用于判断所述目标纳米结构是否满足广角成像要求；
所述更新单元用于，在存在不满足广角成像要求的目标纳米结构的情况下，选取新的第二纳米结构，并以所述第二纳米结构代替所述不满足广角成像要求的目标纳米结构，生成新的纳米结构集；所述第二纳米结构与所述不满足广角成像要求的目标纳米结构对所述主入射光的调制相位相同，且所述第二纳米结构与所述不满足广角成像要求的目标纳米结构具有不同的形状。
第三方面，本发明实施例提供了一种电子设备，包括总线、收发器、存储器、处理器及存储在所述存储器上并可在所述处理器上运行的计算机程序，所述收发器、所述存储器和所述处理器通过所述总线相连，所述计算机程序被所述处理器执行时实现上述任意一项所述的超表面的设计方法中的步骤。
第四方面，本发明实施例还提供了一种计算机可读存储介质，其上存储有计算机程序，所述计算机程序被处理器执行时实现上述任意一项所述的超表面的设计方法中的步骤。
本发明实施例提供的超表面的设计方法、装置、电子设备及计算机可读存储介质，以对主入射光的调制相位作为基准，选取n个不同调制相位的纳米结构(如第一纳米结构)，通过分析其在不同入射角度的入射光下的性能参数确定所选取的纳米结构是否满足广角成像要求，并将不满足广角成像要求的纳米结构替换为其他形状的纳米结构，实现更新，从而可以寻找到谐振响应较小的纳米结构，进而利用更新后的n个纳米结构设计超表面，所设计的超表面对不同入射角度的入射光具有比较稳定的调制效果，整体性能较好，可以适用于广角成像的场景，能够提高广角成像质量。
附图说明
为了更清楚地说明本发明实施例或背景技术中的技术方案，下面将对本发明实施例或背景技术中所需要使用的附图进行说明。
图1示出了本发明实施例所提供的一种超表面的设计方法的流程图；
图2示出了本发明实施例所提供的一种超表面的设计方法的详细流程图；
图3示出了本发明实施例所提供的圆柱形纳米结构的结构示意图；
图4A示出了本发明实施例所提供的8个圆柱形的目标纳米结构在不同入射角下的透射率；
图4B示出了本发明实施例所提供的8个圆柱形的目标纳米结构在不同入射角下的相位；
图5A示出了本发明实施例所提供的入射角为0°下不同目标纳米结构的透射率和相位；
图5B示出了本发明实施例所提供的入射角为30°下不同目标纳米结构的透射率和相位；
图6示出了本发明实施例所提供的十字柱形纳米结构的结构示意图；
图7示出了本发明实施例所提供的更换序号为3的目标纳米结构形成新的纳米结构集的示意图；
图8A示出了本发明实施例所提供的序号为2的目标纳米结构的透射率随入射角的变化情况；
图8B示出了本发明实施例所提供的序号为2的目标纳米结构的相位随入射角的变化情况；
图9示出了本发明实施例所提供的替换前后第一平均透射率的对比图；
图10示出了本发明实施例所提供的一种超表面的设计装置的结构示意图；
图11示出了本发明实施例所提供的一种用于执行超表面的设计方法的电子设备的结构示意图。
具体实施方式
在实现本发明创造的过程中，发明人发现，谐振响应的谐振模式是一种电场分布，其除了与光线的入射角度相关外，还与纳米结构的形状相关，当纳米结构的形状改变时，同一入射角度下可能不再存在谐振响应。因此，本发明实施例通过替换不同形状的纳米结构，从而可以设计出在大角度入射时仍然具有高性能的超表面。
图1示出了本发明实施例所提供的一种超表面的设计方法的流程图。如图1所示，该方法包括：
步骤101：确定n个第一纳米结构，不同的第一纳米结构对主入射光的调制相位不同；该主入射光为以主入射角度入射的入射光，n≥2。
本发明实施例中，在设计超表面时，需要首先确定具有不同调制功能的纳米结构，即不同的纳米结构的调制相位不同，为方便描述，本发明实施例将初次选取的纳米结构称为第一纳米结构。对于初次选取的n个第一纳米结构，所有的第一纳米结构可以具有相同的形状。本发明实施例中，“形状”指的可以是纳米结构的立体形状，包括圆柱形、方柱形、矩形柱形、圆环柱形等；并且，该“形状”只用于表征纳米结构的外形特点，而不限定纳米结构的尺寸大小；例如，两个纳米结构均为圆柱形，即使二者的尺寸不同(例如，高度不同、半径不同等)，二者也是具有相同形状的纳米结构。
其中，在选取纳米结构(包括第一纳米结构以及下述的第二纳米结构)时，以主入射光入射至该纳米结构时的调制相位为基准来选取具有不同调制相位的纳米结构；该主入射光为以某一特定的主入射角度入射的入射光，该主入射角度可以为预先设置的，不同的纳米结构均以该主入射角度为基准即可。例如，一般情况下，超表面主要用于对正入射(即入射角度为0°)的光线进行调制，故可以将正入射的光线作为主入射光，相应地，该主入射角度可以为0°±Δ，Δ表示在误差允许范围内的角度值；该角度值Δ为一个较小的值，例如，Δ＝1°、5°等。理想情况下，可以取Δ＝0，即该主入射角度为0°。
本领域技术人员可以理解，本发明实施例中，以主入射角度入射至纳米结构的光均可称为主入射光，该主入射光并不特指某唯一的光线，只要光线的入射角度为该主入射角度，该光线即可作为主入射光。
步骤102：对包括n个目标纳米结构的纳米结构集循环执行更新操作，直至纳米结构集中所有目标纳米结构均满足广角成像要求；最初的目标纳米结构为相应的第一纳米结构；
其中，上述步骤102中的“更新操作”包括以下步骤1021-1022。
步骤1021：获取每个目标纳米结构的性能信息，性能信息包括在不同入射角度的入射 光下目标纳米结构的性能参数，性能参数包括透射率和/或调制相位；目标纳米结构的性能信息用于判断目标纳米结构是否满足广角成像要求。
步骤1022：在存在不满足广角成像要求的目标纳米结构的情况下，选取新的第二纳米结构，并以第二纳米结构代替不满足广角成像要求的目标纳米结构，生成新的纳米结构集；第二纳米结构与不满足广角成像要求的目标纳米结构对主入射光的调制相位相同，且第二纳米结构与不满足广角成像要求的目标纳米结构具有不同的形状。
本发明实施中，由于谐振响应的存在，极易导致初次选取的n个第一纳米结构中至少部分第一纳米结构不适合广角成像；例如，主入射角度为0°，某第一纳米结构对主入射光虽然具有所需的调制相位，但当光线以较大入射角度入射至该第一纳米结构时，该第一纳米结构所调制的相位大小会发生较大的变化。例如，某第一纳米结构A对0°入射的主入射光的调制相位为π/2，而该第一纳米结构A对以20°入射的其他入射光的调制相位可能为π/4、甚至接近于0等，调制相位变化较大。因此，本发明实施例通过循环更新纳米结构，以使得最终得到的所有纳米结构均符合要求。
具体地，为方便描述，本发明实施例将n个纳米结构所构成的集合称为纳米结构集，并对该纳米结构集进行更新；由于更新过程中会替换纳米结构，为能够与最初的第一纳米结构进行区分，本发明实施例将该纳米结构集中的纳米结构称为“目标纳米结构”。在初始时，该纳米结构集由n个第一纳米结构构成，即每个第一纳米结构均作为一个目标纳米结构，形成具有n个目标纳米结构的初始的纳米结构集，且每个目标纳米结构对主入射光的调制相位不同。之后，循环更新该纳米结构集。
本发明实施例中，通过循环执行更新操作实现对纳米结构集的更新；其中，通过判断目标纳米结构是否满足广角成像要求来确定该目标纳米结构是否需要被替换，通过替换不满足广角成像要求的目标纳米结构实现对纳米结构集的更新。本发明实施例中，利用目标纳米结构的性能信息判断该目标纳米结构是否满足广角成像要求。其中，广角成像要求指的是在广角范围内均能够实现成像的要求；该“广角”指的是具有一定范围的入射角度，该入射角度的范围具体基于实际情况而定，例如，广角对应的范围可以为0～30°、20°～60°等。一般情况下，广角对应的范围包含主入射角度；为使目标纳米结构能够满足该广角成像要求，需要目标纳米结构对多个入射角度的入射光均具有良好且稳定的调制效果。
具体地，每个目标纳米结构的性能信息包括在不同入射角度的入射光下该目标纳米结构的性能参数，且该性能参数包括透射率和/或调制相位。例如，该性能参数包括透射率和调制相位，通过分析不同入射角度的入射光射向该目标纳米结构后，该目标纳米结构的透射率和调制相位，即可确定该目标纳米结构的性能信息；例如，该性能参数具体可以表现为：透射率与入射角度之间的关系、调制相位与入射角度之间的关系。本发明实施例中，该性能信息能够表示目标纳米结构对不同入射角度入射光的调制效果，基于该性能信息即可判断相应的目标纳米结构是否满足广角成像要求。一般情况下，目标纳米结构的透射率越高，调制相位的变化越小，越容易满足广角成像要求。
若某个目标纳米结构的性能参数较差，则该目标纳米结构不满足广角成像要求，本发明实施例会替换该性能参数较差的目标纳米结构，即替换不满足广角成像要求的目标纳米结构。具体地，基于该性能参数较差的目标纳米结构对主入射光的调制相位，选取对主入 射光具有相同调制相位的新的纳米结构，为方便区分，本发明实施例将新选取的纳米结构称为第二纳米结构。例如，性能参数较差的目标纳米结构对主入射光的调制相位为π/2，则该第二纳米结构对主入射光的调制相位也为π/2。需要说明的是，只要某纳米结构与性能参数较差的目标纳米结构对主入射光的调制相位之差在允许的范围内，则可认为二者对主入射光的调制相位相同，该纳米结构就有可能被作为第二纳米结构，可以不要求二者的调制相位完全相同。
并且，为能够规避掉谐振响应，所选的第二纳米结构与性能参数较差的目标纳米结构的形状不同。例如，性能参数较差的目标纳米结构为圆柱形，则可以选取其他形状(例如方柱形、十字柱形等)的纳米结构作为第二纳米结构。可选地，不同形状的纳米结构的调制效果可能也受入射光线偏振态的影响，某些形状的纳米结构对偏振不敏感，即偏振不相关，例如，圆柱形、方柱形、十字柱形、圆孔方柱形等纳米结构；而某些形状的纳米结构对偏振敏感，即偏振相关，例如，椭圆柱形、矩形柱形、六棱柱形等纳米结构。本发明实施例中，偏振相关的纳米结构之间可以替换，偏振不相关的纳米结构之间也可以替换。具体地，最初的第一纳米结构与任一重新选取的第二纳米结构均为偏振相关结构；或者，最初的第一纳米结构与任一重新选取的第二纳米结构均为偏振不相关结构。
本发明实施例中，将不满足广角成像要求的目标纳米结构替换为其他形状的第二纳米结构，形成新的纳米结构集，之后即可对该新的纳米结构集再次执行更新操作，实现循环迭代，并最终得到所有目标纳米结构均满足广角成像要求的纳米结构集。若n个目标纳米结构均满足广角成像要求，如上述步骤102所示，此时可以停止循环，即不再执行更新操作，此时所确定的n个目标纳米结构为符合要求的纳米结构，可以用其设计制作超表面。
本领域技术人员可以理解，在循环过程中，对于某一时刻的纳米结构集，可能只有一个目标纳米结构不满足广角成像要求，也可能存在多个(甚至全部)目标纳米结构不满足广角成像要求，而在一轮的更新操作中，可以只替换性能最差的目标纳米结构，也可以替换所有不满足广角成像要求的目标纳米结构，本实施例对此不做限定。
此外，本发明实施例中“新的第二纳米结构”指的可以是：只与性能参数较差的目标纳米结构相比，该第二纳米结构是新的；例如，与之前曾经使用的其他第二纳米结构相比，此时的第二纳米结构可以是尺寸不同但形状相同的纳米结构。或者，一般情况下，为方便制作超表面，所选的n个纳米结构需要是高度相同的，而在该高度的约束下，不同尺寸(如半径)的纳米结构所调制的相位一般是不同的，且调制某一相位的纳米结构只有一种尺寸，故此时最好通过改变形状来替换第二纳米结构；相应地，该第二纳米结构与对主入射光具有同一调制相位的第一纳米结构以及对主入射光具有同一调制相位的曾经选取的其他第二纳米结构均形状不同。例如，对主入射光的调制相位为π/2的纳米结构，第一轮更新操作所选用的是圆柱形纳米结构(即相应的第一纳米结构为圆柱形)，其不符合要求，此时可以选用十字柱形纳米结构作为第二纳米结构；在第二轮更新操作过程中，若该十字柱形纳米结构仍然不符合要求，则需要选择不是圆柱形、也不是十字柱形的纳米结构，例如方柱形纳米结构等，以使得当前选取的第二纳米结构与曾经的任一纳米结构(包括最初的第一纳米结构以及之前轮选取的其他第二纳米结构)的形状均不同。
需要说明的是，对于主入射角度对应的某一调制相位，若遍历所有纳米结构后仍不能 得出符合要求的纳米结构，则可以更改纳米结构的其他参数，例如更改纳米结构的高度、周期等，重新执行上述步骤101-102；或者，在允许的情况下，也可适当降低对性能参数的要求，即更低的性能参数也可以满足广角成像要求，以能够得到符合要求的纳米结构集。
步骤103：基于纳米结构集设计超表面。
本发明实施例中，在得到满足广角成像要求的n个目标纳米结构后，即可基于这些目标纳米结构设计超表面。例如，根据该超表面所需要实现的功能，可以确定该超表面的相位分布该相位分布能够表示位置(x,y)处的相位值；基于该相位分布即可确定超表面任一位置处需要哪一目标纳米结构，从而设计得到超表面。本领域技术人员可以理解，步骤103所得到的超表面本质为超表面模型，其包括该超表面不同位置处纳米结构的结构参数(如半径、高度等)，后续需要基于相应的制作工艺(例如光刻工艺)得到实际所需的超表面。
设计超表面所需的纳米结构的调制相位应当能够覆盖0至2π。本发明实施例中，可以选取覆盖0至2π的纳米结构中的一部分作为n个第一纳米结构；或者，为了提高设计效率，也可以将覆盖0至2π的纳米结构均作为n个第一纳米结构，即n个第一纳米结构所调制的相位能够覆盖0至2π。具体地，本发明实施例以对主入射光的调制相位为基准，n个第一纳米结构对主入射光的调制相位至少能够覆盖0至2π；并且，为保证超表面的整体性能效果，可以选取较大的n值，例如，n≥4或n≥6，或者，n≥8。
本领域技术人员可以理解，由于0至2π之间具有无穷多个相位，不可能绝对覆盖0至2π，本发明实施例中的“能够覆盖0至2π”指的是在误差允许范围内相对地能够覆盖0至2π。例如，对于调制相位分布比较均匀的n个纳米结构，若其最大相位与最小相位之差接近2π，只要n足够大，即可认为这n个纳米结构的调制相位能够覆盖0至2π。例如，n＝8，8个纳米结构对主入射光的调制相位依次为则可认为这8个纳米结构对主入射光的调制相位能够覆盖0至2π，这8个纳米结构可以作为第一纳米结构。
此外，需要说明的是，多个纳米结构能够覆盖0至2π，指的是多个纳米结构的相位所对应的跨度能够达到2π，并不限定纳米结构的相位必须在[0,2π]，这些纳米结构的相位是基于其中一个纳米结构的相对相位。例如，除第一个纳米结构之外，其余n-1个纳米结构的相位都是以该第一个纳米结构的相位为基准所确定的，该第一个纳米结构的相位可以为0，也可以为其他任意值，其他n-1个纳米结构的相位依次递增(或递减)，得到能够覆盖0至2π的n个纳米结构。例如，上述的能够覆盖0至2π的8个纳米结构对主入射光的调制相位依次为该可以为任意值；这8个纳米结构的相位可以为任意值，但相邻两个纳米结构的相位差始终为为方便描述，本实施例以8个纳米结构对主入射光的调制相位依次是为例说 明。
本发明实施例提供的超表面的设计方法，以对主入射光的调制相位作为基准，选取n个不同调制相位的纳米结构(如第一纳米结构)，通过分析其在不同入射角度的入射光下的性能参数确定所选取的纳米结构是否满足广角成像要求，并将不满足广角成像要求的纳米结构替换为其他形状的纳米结构，实现更新，从而可以寻找到谐振响应较小的纳米结构，进而利用更新后的n个纳米结构设计超表面，所设计的超表面对不同入射角度的入射光具有比较稳定的调制效果，整体性能较好，可以适用于广角成像的场景，能够提高广角成像质量。
在上述实施例的基础上，由于性能参数可以包含多项，例如包含透射率和调制相位两项，相应地，广角成像要求也可分为多项，例如分为广角成像透射率要求、广角成像相位要求等。具体地，本发明实施例中，在性能参数包括透射率的情况下，该广角成像要求包括广角成像透射率要求。并且，目标纳米结构在不同入射角度的入射光下的透射率越大，越能够满足广角成像透射率要求。相应地，若目标纳米结构的透射率越小，则越可能不满足广角成像要求。
可选地，对于单一的纳米结构，发明人发现，较难保证其对不同入射角度的入射光均具有较高的透射率，而若将判断是否满足广角成像透射率要求的阈值设置得较低，则会大大降低所设计超表面的整体性能。因此，本发明实施例利用多个目标纳米结构整体的平均透射率来判断是否满足广角成像透射率要求。具体地，该更新操作还包括以下步骤A1-A2：
步骤A1：确定每个入射角度对应的第一平均透射率，第一平均透射率为多个目标纳米结构在入射角度的入射光下的透射率的加权平均值。
本发明实施例中，在性能参数包括透射率的情况下，每个目标纳米结构的性能信息均包括多个入射角度对应的透射率，即在多个入射角度的入射光下目标纳米结构的透射率。本发明实施例对同一入射角度、多个不同目标纳米结构的透射率进行加权平均，可以确定该入射角度所对应的平均透射率，即第一平均透射率；通过对每个入射角度所对应的性能信息均进行相应的加权平均处理，即可得到每个入射角度对应的第一平均透射率。该第一平均透射率能够表示多个目标纳米结构对以该入射角度入射的光线的平均透射率。
可选地，上述步骤A1“确定每个入射角度对应的第一平均透射率”包括以下步骤A11。
步骤A11：确定每个目标纳米结构的权重，根据权重对多个目标纳米结构在入射角度的入射光下的透射率进行加权处理，得到该入射角度对应的第一平均透射率。其中，不同的目标纳米结构的权重相同，或者，目标纳米结构的权重与超表面中与该目标纳米结构对应同一调制相位的纳米结构的数量之间为正相关关系。
并且，该第一平均透射率满足：
其中，wi表示第i个目标纳米结构的权重，ti,j表示第i个目标纳米结构在第j个入射角度的入射光下的透射率，表示第j个入射角度对应的第一平均透射率。一般情况下， 为实现加权平均，所有权重之和为1，即
本发明实施例中，可以预先为每种目标纳米结构设置权重，例如，第i个目标纳米结构的权重为wi，i＝1,2,…,n；并且，上述步骤1022中的替换过程也会改变该权重。其中，可以为不同的目标纳米结构设置相同的权重，即w1＝w2＝…＝wn；或者，由于所确定的n个目标纳米结构最终用于设计超表面，为保证该超表面的整体透射率较好，可以基于超表面所需的每种调制相位对应的纳米结构的数量来设置相应的目标纳米结构的权重，且二者之间为正相关关系，例如，二者之间为正比例关系。基于超表面中每种纳米结构的数量来确定相应目标纳米结构的权重，可以使得所设计的超表面具有更好的性能。
例如，设计超表面需要4种纳米结构，n＝4，且4种纳米结构对主入射光的调制相位依次为0、π/2、π、3π/2，若所设计的超表面共需要100个纳米结构(此处仅为举例说明，实际中所需的纳米结构数量远大于100)，其中，需要10个调制相位为0的纳米结构、需要20个调制相位为π/2的纳米结构、需要30个调制相位为π的纳米结构、需要40个调制相位为3π/2的纳米结构，相应地，可以将对主入射光的调制相位分别为0、π/2、π、3π/2的4种目标纳米结构的权重依次设为0.1、0.2、0.3、0.4。
并且，本发明实施例中，可以获取每个目标纳米结构在不同入射角度下的透射率；例如，若入射角度共具有m个，则以确定任一目标纳米结构对任一入射角度的透射率，并以ti,j表示第i个目标纳米结构在第j个入射角度的入射光下的透射率，其中，i＝1,2,…,n；j＝1,2,…,m。在确定第j个入射角度下n个目标纳米结构的透射率后，即可基于上式(1)确定该第j个入射角度对应的第一平均透射率
本发明实施例中，可以在广角所对应的范围内选取m个间隔均匀的角度作为需要分析的入射角度。例如，广角的范围为0～30°，则可以设置0、1°、2°、…、30°共31个入射角度，即m＝31。之后可以确定每个入射角度对应的第一平均透射率其中，主入射角度也为其中一个入射角度。
步骤A2：在至少一个第一平均透射率低于第一预设透射率阈值的情况下，确定至少一个目标纳米结构不满足广角成像透射率要求。
本发明实施例中，该第一平均透射率表示整个纳米结构集的整体性能，若其中一个或多个入射角度对应的第一平均透射率低于第一预设透射率阈值，则说明该纳米结构集的整体性能不满足要求，该纳米结构集中至少有一个目标纳米结构是不满足广角成像透射率要求的，即存在不满足广角成像要求的目标纳米结构，此时需要执行上述步骤1022。相反地，若所有入射角度对应的第一平均透射率均不低于(大于或等于)该第一预设透射率阈值，则说明该纳米结构集满足所需的要求，此时可以认为该纳米结构集中所有目标纳米结构均满足广角成像透射率要求。
可选地，由于超表面一般主要工作于主入射角度对应的场景，对主入射角度的透射率要求可以设置得更高。具体地，本发明实施例中，设置比第一预设透射率阈值更大的第二预设透射率阈值，并对主入射角度对应的第一平均透射率进行判断，若该主入射角度对应的第一平均透射率低于第二预设透射率阈值，则也认为该纳米结构集不符合要求。相反地，在所有第一平均透射率均不低于第一预设透射率阈值、且主入射角度对应的第一平均透射率不低于第二预设透射率阈值的情况下，确定所有目标纳米结构均满足广角成像透射率要求，可以利用这些目标纳米结构设计超表面。例如，该第一预设透射率阈值可以为0.8，该第二预设透射率阈值可以为0.9。
可选地，若整体的第一平均透射率不满足要求，可以进一步基于每个目标纳米结构自身的透射率来确定具体哪个或哪些目标纳米结构不满足广角成像透射率要求，具体地，上述步骤A2“确定至少一个目标纳米结构不满足广角成像透射率要求”可以包括以下步骤A21。
步骤A21：将具有最低透射率或具有最低第二平均透射率的目标纳米结构作为不满足广角成像透射率要求的目标纳米结构；第二平均透射率为目标纳米结构在多个入射角度的入射光下的透射率的平均值。
本发明实施例中，若与其他目标纳米结构相比，某目标纳米结构具有最低的透射率，则可以认为该目标纳米结构不满足广角成像透射率要求。或者，也可以确定每个目标纳米结构自身的平均透射率，即第二平均透射率，若某目标纳米结构具有最低的第二平均透射率，则可以认为该目标纳米结构不满足广角成像透射率要求。具体地，本发明实施例将目标纳米结构在多个入射角度的入射光下的透射率的平均值作为该目标纳米结构的第二平均透射率。例如，对于第i个目标纳米结构，其在第j个入射角度的入射光下的透射率为ti,j，则该第i个目标纳米结构的第二平均透射率满足：其中，m表示入射角度的种类数。
需要说明的是，在需要确定具体哪个目标纳米结构不满足广角成像透射率要求，可以只将最低透射率或最低第二平均透射率对应的目标纳米结构作为不满足广角成像透射率要求的目标纳米结构；或者，进一步地，还可以将其他透射率较低或第二平均透射率较低(例如，第二低)的目标纳米结构也作为不满足广角成像透射率要求的目标纳米结构，本发明实施例对此不做限定。
此外可选地，也可以直接比较纳米结构的透射率是否足够大。具体地，上述更新操作还包括步骤A3-A4：
步骤A3：判断每个目标纳米结构的透射参数是否低于第三预设透射率阈值；目标纳米结构的透射参数包括：目标纳米结构的透射率中的最小值，或者，目标纳米结构的第二平均透射率；第二平均透射率为目标纳米结构在多个入射角度的入射光下的透射率的平均值。
步骤A4：在存在透射参数低于第三预设透射率阈值的目标纳米结构的情况下，将具有最低透射参数的目标纳米结构作为不满足广角成像透射率要求的目标纳米结构。
本发明实施例中，可以确定某个目标纳米结构的透射率中的最小值，每个目标纳米结构均对应一个透射率的最小值(不同于前述的最低透射率，该最低透射率为所有目标纳米结构的透射率中的最小值)，或者，与上述步骤A21相似，确定目标纳米结构的第二平均透射率，将该透射率的最小值或第二平均透射率作为相应目标纳米结构的透射参数，通过比较该透射参数是否低于第三预设透射率阈值，来确定目标纳米结构是否满足广角成像透射率要求；一般情况下，该第三预设透射率阈值小于第一预设透射率阈值。
其中，若存在透射参数低于第三预设透射率阈值的目标纳米结构，即至少一个目标纳米结构的透射参数低于该第三预设透射率阈值，此时也可说明至少一个目标纳米结构不满足广角成像透射率要求。本发明实施例中，可以只将具有最低透射参数(即具有最低透射率或具有最低第二平均透射率)的目标纳米结构作为不满足广角成像透射率要求的目标纳米结构；或者，进一步地，将透射参数低于第三预设透射率阈值的所有目标纳米结构均作为不满足广角成像透射率要求的目标纳米结构，具体可基于实际情况而定。
可选地，在性能参数包括调制相位的情况下，相应地，该广角成像要求包括广角成像相位要求；目标纳米结构的相位梯度越小，越能够满足广角成像相位要求。其中，目标纳米结构的相位梯度用于表示目标纳米结构的调制相位的变化程度。本发明实施例中，目标纳米结构的调制相位的变化程度越大，说明该目标纳米结构的调制相位越可能存在突变，其与对主入射光的调制相位之间的差异越大，该目标纳米结构越难满足广角成像相位要求。
可选地，上述更新操作还包括以下步骤B1-B2。
步骤B1：确定每个目标纳米结构的相位梯度，目标纳米结构的相位梯度包括：目标纳米结构与相邻的其他目标纳米结构之间的调制相位之差随入射角度变化所具有的变化程度，和/或，目标纳米结构的调制相位随入射角度变化所具有的变化程度。
本发明实施例中，由于性能信息包含多个不同入射角度对应的调制相位，故以调制相位随入射角度的变化所具有的变化程度表示目标纳米结构的相位梯度。具体地，可以将目标纳米结构本身的调制相位随入射角度变化所具有的变化程度作为该目标纳米结构的相位梯度；例如，目标纳米结构的相位梯度满足下式(2)或式(3)：

其中，表示第i个目标纳米结构在第j个入射角度处的相位梯度。
或者，将相邻目标纳米结构之间的调制相位之差随入射角度变化所具有的变化程度作为某个目标纳米结构的相位梯度。本发明实施例中，两个目标纳米结构相邻，指的是两个目标纳米结构对主入射光的调制相位大小相邻。例如，基于目标纳米结构对主入射光的调制相位大小对多个目标纳米结构进行排序，则第i个目标纳米结构与第i-1个以及第i+1个目标纳米结构相邻。例如，对于第i个目标纳米结构，其在第j个入射角度处对应的相位梯 度可以表示为下式(4)或式(5)：

或者，也可综合左右两个相邻的目标纳米结构的调制相位，例如，该目标纳米结构的相位梯度满足下式(6)：
本领域技术人员可以理解，若n个目标纳米结构对主入射光的调制相位正好能够覆盖0至2π，由于纳米结构的调制相位是以2π为周期的，例如，0与2π、4π等本质上是相同的，因此，第1个目标纳米结构与第n个目标纳米结构也是相邻的；例如，
步骤B2：在目标纳米结构的相位梯度高于相应的预设梯度阈值的情况下，确定相位梯度高于预设梯度阈值的目标纳米结构不满足广角成像相位要求。
本发明实施例中，无论上式(2)或式(3)所示的第一种相位梯度，或者上式(4)、式(5)或式(6)所示的第二种相位梯度，均是越小越好，即目标纳米结构的相位梯度越小，越可能满足相应的广角成像相位要求。相反地，如上述步骤B2所示，若某目标纳米结构的相位梯度高于预设梯度阈值，则可确定该目标纳米结构不满足广角成像相位要求。
此外，目标纳米结构的相位梯度存在上述两种，可以分别为每一种相位梯度设置相应的预设梯度阈值；在实际应用过程中，可以只确定其中一种相位梯度。或者，若确定目标纳米结构的两种相位梯度，则在其中任意一种相位梯度高于相应的预设梯度阈值的情况下，即可认为目标纳米结构不满足广角成像相位要求；相应地，若目标纳米结构的两种相位梯度均低于相应的预设梯度阈值，则可认为该目标纳米结构满足广角成像相位要求。
此外可选地，可以将目标纳米结构的相位梯度与预设梯度阈值直接进行比较。或者，也可通过其他方式实现间接比较。本发明实施例中，上述更新操作还可以包括步骤B3-B4。
步骤B3：确定目标纳米结构在第j个入射角度处的相位梯度与目标纳米结构在主入射角度处的相位梯度之间的变化比，且变化比满足下式(7)：
其中，表示第i个目标纳米结构在第j个入射角度处的相位梯度，表示第i个目标纳米结构在主入射角度处的相位梯度，Ri,j表示第i个目标纳米结构在第j个入射角度处的变化比。
步骤B4：在变化比超过预设比值的情况下，确定目标纳米结构的相位梯度高于相应的预设梯度阈值。
本发明实施例中，上述步骤B1确定的目标纳米结构的相位梯度包括多个入射角度对应的相位梯度，其也包括主入射角度对应的相位梯度，一般情况下，主入射角度处的相位变化不大，即相位梯度较小，本发明实施例以主入射角度对应的相位梯度为基准，利用相位梯度的变化比确定目标纳米结构在其他入射角度处的相位梯度是否满足要求。具体地，对于第i个目标纳米结构，其在主入射角度处的相位梯度为其在其他第j个入射角度处的相位梯度为则可以基于上式(7)确定相应的变化比Ri,j，该变化比Ri,j可以表示相对于主入射角度目标纳米结构的相位梯度的变化百分比。该变化比Ri,j越小，说明第i个目标纳米结构的相位梯度变化越小，其与主入射角度处的相位梯度越接近，越可能满足广角成像相位要求；相反地，若变化比Ri,j超过预设比值，则可确定第i个目标纳米结构的相位梯度高于相应的预设梯度阈值(此时，该预设梯度阈值相当于是基于相位梯度所确定的阈值)，该第i个目标纳米结构不满足广角成像相位要求。例如，该预设比值可以为10％。
此外，本发明实施例中，若性能参数包含透射率和调制相位两项，相应地，广角成像要求包括广角成像透射率要求和广角成像相位要求，基于目标纳米结构是否满足广角成像透射率要求和广角成像相位要求，确定该目标纳米结构是否满足广角成像要求；其中，目标纳米结构满足广角成像透射率要求是其满足广角成像要求的必要条件，目标纳米结构满足广角成像相位要求也是其满足广角成像要求的必要条件。例如，若目标纳米结构不满足广角成像透射率要求、或者不满足广角成像相位要求，则可认为该目标纳米结构不满足广角成像要求；若目标纳米结构既满足广角成像透射率要求、又满足广角成像相位要求，则认为该目标纳米结构满足广角成像要求。
可选地，本发明实施例可以预先确定纳米结构的性能信息，在步骤1021中需要获取相应目标纳米结构的性能信息时，可以直接查询或调用相应的性能信息。具体地，本发明实施例中，在上述步骤102“对包括n个目标纳米结构的纳米结构集循环执行更新操作”之前，该方法还包括：
步骤C1：对多个不同形状的纳米结构进行性能分析，确定每个纳米结构的性能信息。
本发明实施例中，预先对多个不同形状(或者，所有不同形状)的纳米结构进行分析，可以提前确定大量纳米结构的性能信息，进而建立相应的数据库，方便后续使用。并且，在确定第一纳米结构或选取第二纳米结构时，也可利用该数据库初步排除不符合要求的纳米结构，例如排除透射率过低或相位梯度过大的纳米结构，可以提高后续更新操作的效率，能够更快速地确定满足广角成像要求的纳米结构集。
可选地，上述步骤“对多个不同形状的纳米结构进行性能分析”的一种实施方式可以参见以下步骤C11-C12。
步骤C11：以多个同一纳米结构构成与纳米结构对应的测试超表面，并以不同入射角 度向测试超表面出射入射光。
本发明实施例中，在分析某一纳米结构的性能信息时，构建全部由该纳米结构构成的超表面，即测试超表面，该测试超表面所具有的纳米结构均为该需要分析的纳米结构。其中，该测试超表面一般为模拟的超表面，通过仿真测试等方式即可形成该测试超表面，并实现不同入射角度下的测试分析。
步骤C12：将所述测试超表面在不同入射角度的入射光下的性能参数作为所述纳米结构相应的性能参数。
本发明实施例中，该测试超表面与相应的纳米结构具有相同的性能参数，故通过确定该测试超表面的性能参数即可得到相应纳米结构的性能参数。在确定测试超表面的性能参数的过程中，可以将某点作为参考点，确定该参考点的性能参数。例如，上述步骤C12可以包括：确定在测试超表面出光侧的参考点处的性能参数，将参考点处的性能参数作为纳米结构的性能参数；参考点与测试超表面的中心对应，且与测试超表面的中心之间的间距小于预设距离。在测试超表面的出光侧选取参考点，通过检测该参考点处的性能参数确定该纳米结构的性能参数。其中，该参考点可以位于测试超表面的中心对应的位置，且距离测试超表面的距离较近，例如，距离1um。
下面通过一个实施例详细介绍该超表面的设计方法的流程。
参见图2所示，该超表面的设计方法包括步骤201-209。
步骤201：对多个不同形状的纳米结构进行性能分析，确定每个纳米结构的性能信息。
其中，可以对圆柱形、方柱形、十字柱形等多种不同形状、不同尺寸(例如，不同的高度、半径、周期等)的纳米结构进行性能分析，确定每个纳米结构在不同入射角度下对应的透射率和调制相位。并且，本发明实施例中的主入射角度为0°，即主入射光为正入射的光线，且性能分析的角度范围为0～30°；相应地，该性能信息包括0～30°对应的透射率和调制相位。
步骤202：确定8个第一纳米结构，不同的第一纳米结构对主入射光的调制相位不同。
本发明实施例中，选取8个离散相位点8个第一纳米结构对主入射光的调制相位分别满足上述8个离散相位点。为方便描述，本发明实施例按照所调制相位的大小对8个第一纳米结构进行排序：第一纳米结构1表示序号为1的第一纳米结构，其对主入射光的调制相位为0；第一纳米结构2表示序号为2的第一纳米结构，其对主入射光的调制相位为……，第一纳米结构8表示序号为8的第一纳米结构，其对主入射光的调制相位分别为
步骤203：将8个第一纳米结构分别作为相应的目标纳米结构，生成最初的纳米结构集。
相应地，目标纳米结构1表示序号为1的目标纳米结构，其对主入射光的调制相位为0；目标纳米结构2表示序号为2的目标纳米结构，其对主入射光的调制相位为……， 目标纳米结构8表示序号为8的目标纳米结构，其对主入射光的调制相位分别为
步骤204：获取8个目标纳米结构的性能信息。
其中，若该8个目标纳米结构为上述的8个第一纳米结构，则可以基于上述步骤201所确定的数据查询得到该8个目标纳米结构的性能信息；或者，若该8个目标纳米结构中包含新替换的目标纳米结构，此时只需要获取该新替换的性能信息。
本发明实施例中，所设计的超表面以硅(Si)作为纳米结构的材料，以二氧化硅(SiO2)作为纳米结构的衬底；并且，纳米结构的高度和周期是预设的，通过改变纳米结构的截面尺寸(如半径、直径等)来改变纳米结构的相位调制效果，即不同截面尺寸的纳米结构，具有不同的调制相位。本发明实施例中，超表面中纳米结构的高度为600nm，周期为490nm，其工作波长为850nm。本发明实施例选取圆柱形的纳米结构作为第一纳米结构，经分析，直径D分别为D＝150,166,176,184,188,193,200,213(单位，nm)的纳米结构可满足上述8个离散相位点的要求，将其依次编号1至8，并作为初始的8个目标纳米结构。
其中，初始的8个目标纳米结构均为圆柱形，圆柱形的目标纳米结构的示意图可参见图3所示；并且，8个目标纳米结构的性能信息可参见图4A和图4B所示，图4A和图4B中的1至8表示8个目标纳米结构的序号。其中，图4A表示8个圆柱形的目标纳米结构在不同入射角下的透射率，图4B表示8个圆柱形的目标纳米结构在不同入射角下的相位(即上述的调制相位，单位为rad)。由图4A、4B可知，目标纳米结构2、3、4、5在部分入射角下的透射率较小，目标纳米结构3、4、5的相位梯度较大。
图5A和图5B示出了入射角为0°和30°下不同目标纳米结构的透射率和相位。由图5A和图5B可知，虽然8个目标纳米结构基本可以实现0至2π的相位全覆盖，且如图5A所示，正入射时各目标纳米结构均表现为高于0.9的透射率，但如图5B所示，在入射角为30°时，序号为3、4、5的目标纳米结构的透射率均低于0.6，甚至最小透射率约为0.2。如果将上述8个目标纳米结构用于设计制造超表面，则该超表面只能在小角度范围内使用，在大角度时光学性能将急剧下降。通过本发明实施例提供的方法，可以筛选并替换其中较差的目标纳米结构，具体可参见如下所示的步骤。
步骤205：确定每个入射角度对应的第一平均透射率，并确定每个目标纳米结构的相位梯度。
步骤206：判断第一平均透射率是否高于第一预设透射率阈值，且相位梯度是否低于预设梯度阈值，若是，执行步骤208，否则执行步骤207。
步骤207：确定不满足广角成像要求的目标纳米结构，并用新的第二纳米结构代替该不满足广角成像要求的目标纳米结构，生成新的纳米结构集，并重新执行步骤204。其中，步骤204-207为更新操作。
本发明实施例中，若第一平均透射率不高于第一预设透射率阈值，说明存在不满足广角成像透射率要求的目标纳米结构；具体地，如上述步骤A21所示，可以将具有最低透射率或具有最低第二平均透射率的目标纳米结构作为不满足广角成像透射率要求的目标纳米结构。若目标纳米结构的相位梯度不低于预设梯度阈值，说明该目标纳米结构不满足广角成像相位要求。本发明实施例可以将不满足广角成像透射率要求和/或不满足广角成像相位 要求的目标纳米结构作为不满足广角成像要求的目标纳米结构，并用新的第二纳米结构代替，该第二纳米结构作为新的目标纳米结构，进而可以生成新的包含8个目标纳米结构的纳米结构集。
如上所述，本发明实施例所选取的圆柱形的目标纳米结构3(即序号为3的目标纳米结构)的透射率和相位均不满足要求，其透射率较低，且相位梯度较大，故该目标纳米结构3为一个不满足广角成像要求的目标纳米结构；本发明实施例选取十字柱形的纳米结构作为第二纳米结构，并替换圆柱形的目标纳米结构3，形成新的目标纳米结构3以及新的纳米结构集。其中，该十字柱形的纳米结构的示意图可参见图6所示，更换目标纳米结构3形成新的纳米结构集的示意图可参见图7所示。
本发明实施例中，圆柱形的目标纳米结构2、3、4的性能均较差，可以在一次更新操作中一次性替换这三个目标纳米结构。具体地，本发明实施例中以三个十字柱形的第二纳米结构替换圆柱形的目标纳米结构2、3、4。十字柱形的臂长a和臂宽b的定义可参见图6所示，且其高度h不变，仍然为600nm；经测试，臂长a＝428,480,460nm、臂宽b＝143,160,130nm的三个十字柱形纳米结构对正入射光线(即主入射光)的调制相位分别约为三者可以替换圆柱形的目标纳米结构2、3、4。
图5B所对应的参数具体可参见下表1，表1示出了在入射角度为30°时，圆柱形的8个目标纳米结构的参数。
表1
所选的三个十字柱形纳米结构的参数可参见下表2所示。
表2
对比表1和表2可知，这三个十字柱形的第二纳米结构比圆柱形的目标纳米结构2、3、4具有更优的性能，将三个十字柱形的第二纳米结构作为新的目标纳米结构2、3、4，可以提升新的纳米结构集的整体性能。
并且，本发明实施例还提供了序号为2的目标纳米结构的透射率和相位随入射角的变化情况，具体可参见图8A和图8B所示；其中，每个图均对应有圆柱形的目标纳米结构和十字柱形目标纳米结构。基于图8A和图8B可知，十字柱形的目标纳米结构2的透射率在 所分析的全角度范围内(即0～30°范围内)都表现为较高透射率，而且相位突变不明显。因此，本发明实施例中，通过将圆柱形的目标纳米结构替换为十字柱形的第二纳米结构，可以提升新的纳米结构集的透射率和调制相位等性能。
在生成新的纳米结构集之后，即可执行下一轮的更新操作，即可以重新执行上述步骤204，进而确定该新的纳米结构集中目标纳米结构的透射率和相位梯度等，以判断其是否满足相位成像要求。
本发明实施例以表2所对应的三个十字柱形纳米结构(第二纳米结构)替换圆柱形的目标纳米结构2、3、4，可以得到替换后结构(包含5个圆柱形纳米结构和3个十字柱形纳米结构)，替换后结构的第一平均透射率具体可参见图9所示；并且，图9对比示出了原全圆柱结构(包含8个圆柱形纳米结构)的第一平均透射率，图9纵坐标的平均透射率为第一平均透射率。由图9可知，替换后结构在正入射有高于0.9的第一平均透射率，而且大角度下的透射率仍保持高于0.85的较高数值；不同于替换前全为圆柱结构时的低第一平均透射率的状况。替换后的纳米结构集透射率更优。类似地，也可分析替换后的纳米结构集的相位梯度，本实施例对此不做详述。
步骤208：确定当前的纳米结构集符合广角成像要求。
本发明实施例中，若所有的第一平均透射率均高于第一预设透射率阈值，则可认为8个目标纳米结构均满足广角成像透射率要求；若每个目标纳米结构的相位梯度均低于预设梯度阈值，则可认为8个目标纳米结构均满足广角成像相位要求。此时可认为8个目标纳米结构均满足广角成像要求，即当前的纳米结构集(包括当前的8个目标纳米结构)符合广角成像要求，可用于设计超表面。
步骤209：基于当前的纳米结构集设计超表面。
本发明实施例提供的超表面的设计方法，通过分析不同几何形状的纳米结构在不同入射角的光学响应情况(包括透射率、调制相位)，采用替换纳米结构的方式，可以将透射率低、相位突变的纳米结构替换为主入射光调制相位相同的其它几何形状的纳米结构，在尽量减少初步设计结构改变的基础上提高所设计的超表面的整体性能，大角度斜入射时也具有较优的透射率和调制相位。
上文详细描述了本发明实施例提供的超表面的设计方法，该方法也可以通过相应的装置实现，下面详细描述本发明实施例提供的超表面的设计装置。
图10示出了本发明实施例所提供的一种超表面的设计装置的结构示意图。如图10所示，该超表面的设计装置包括：
初始模块11，用于确定n个第一纳米结构，不同的所述第一纳米结构对主入射光的调制相位不同；所述主入射光为以主入射角度入射的入射光，n≥2；
更新模块12，用于对包括n个目标纳米结构的纳米结构集循环执行更新操作，直至所述纳米结构集中所有所述目标纳米结构均满足广角成像要求；最初的所述目标纳米结构为相应的所述第一纳米结构；
设计模块13，用于基于所述纳米结构集设计超表面；
其中，所述更新模块12包括获取单元121和更新单元122；
所述获取单元121用于，获取每个所述目标纳米结构的性能信息，所述性能信息包括 在不同入射角度的入射光下所述目标纳米结构的性能参数，所述性能参数包括透射率和/或调制相位；所述目标纳米结构的性能信息用于判断所述目标纳米结构是否满足广角成像要求；
所述更新单元122用于，在存在不满足广角成像要求的目标纳米结构的情况下，选取新的第二纳米结构，并以所述第二纳米结构代替所述不满足广角成像要求的目标纳米结构，生成新的纳米结构集；所述第二纳米结构与所述不满足广角成像要求的目标纳米结构对所述主入射光的调制相位相同，且所述第二纳米结构与所述不满足广角成像要求的目标纳米结构具有不同的形状。
在一种可能的实现方式中，在所述性能参数包括透射率的情况下，所述广角成像要求包括广角成像透射率要求；所述目标纳米结构在不同入射角度的入射光下的透射率越大，越能够满足所述广角成像透射率要求。
在一种可能的实现方式中，所述更新模块12所执行的更新操作还包括：
确定每个所述入射角度对应的第一平均透射率，所述第一平均透射率为多个所述目标纳米结构在所述入射角度的入射光下的透射率的加权平均值；
在至少一个所述第一平均透射率低于第一预设透射率阈值的情况下，确定至少一个目标纳米结构不满足所述广角成像透射率要求。
在一种可能的实现方式中，所述更新模块12所执行的确定每个所述入射角度对应的第一平均透射率，包括：
确定每个所述目标纳米结构的权重，根据所述权重对多个所述目标纳米结构在所述入射角度的入射光下的透射率进行加权处理，得到所述入射角度对应的第一平均透射率；不同的所述目标纳米结构的权重相同，或者，所述目标纳米结构的权重与所述超表面中与所述目标纳米结构对应同一调制相位的纳米结构的数量之间为正相关关系；
所述第一平均透射率满足：
其中，wi表示第i个目标纳米结构的权重，ti,j表示第i个目标纳米结构在第j个入射角度的入射光下的透射率，表示第j个入射角度对应的第一平均透射率。
在一种可能的实现方式中，所述更新模块12所执行的确定至少一个目标纳米结构不满足所述广角成像透射率要求，包括：
将具有最低透射率或具有最低第二平均透射率的目标纳米结构作为不满足所述广角成像透射率要求的目标纳米结构；所述第二平均透射率为所述目标纳米结构在多个所述入射角度的入射光下的透射率的平均值。
在一种可能的实现方式中，所述更新模块12所执行的更新操作还包括：
在所有所述第一平均透射率均不低于第一预设透射率阈值的情况下，确定所有所述目标纳米结构均满足所述广角成像透射率要求；
或者，在所有所述第一平均透射率均不低于第一预设透射率阈值、且所述主入射角度 对应的第一平均透射率不低于第二预设透射率阈值的情况下，确定所有所述目标纳米结构均满足所述广角成像透射率要求；所述第二预设透射率阈值大于所述第一预设透射率阈值。
在一种可能的实现方式中，所述更新模块12所执行的更新操作还包括：
判断每个所述目标纳米结构的透射参数是否低于第三预设透射率阈值；所述目标纳米结构的透射参数包括：所述目标纳米结构的透射率中的最小值，或者，所述目标纳米结构的第二平均透射率；所述第二平均透射率为所述目标纳米结构在多个所述入射角度的入射光下的透射率的平均值；
在存在透射参数低于第三预设透射率阈值的目标纳米结构的情况下，将具有最低透射参数的目标纳米结构作为不满足所述广角成像透射率要求的目标纳米结构。
在一种可能的实现方式中，在所述性能参数包括调制相位的情况下，所述广角成像要求包括广角成像相位要求；所述目标纳米结构的相位梯度越小，越能够满足所述广角成像相位要求；其中，所述目标纳米结构的相位梯度用于表示所述目标纳米结构的调制相位的变化程度。
在一种可能的实现方式中，所述更新模块12所执行的更新操作还包括：
确定每个所述目标纳米结构的相位梯度，所述目标纳米结构的相位梯度包括：所述目标纳米结构与相邻的其他目标纳米结构之间的调制相位之差随入射角度变化所具有的变化程度，和/或，所述目标纳米结构的调制相位随入射角度变化所具有的变化程度；
在所述目标纳米结构的相位梯度高于相应的预设梯度阈值的情况下，确定相位梯度高于预设梯度阈值的目标纳米结构不满足所述广角成像相位要求。
在一种可能的实现方式中，所述更新模块12所执行的更新操作还包括：
确定所述目标纳米结构在第j个入射角度处的相位梯度与所述目标纳米结构在所述主入射角度处的相位梯度之间的变化比，且所述变化比满足：
其中，表示第i个目标纳米结构在第j个入射角度处的相位梯度，表示第i个目标纳米结构在所述主入射角度处的相位梯度，Ri,j表示第i个目标纳米结构在第j个入射角度处的变化比；
在所述变化比超过预设比值的情况下，确定所述目标纳米结构的相位梯度高于相应的预设梯度阈值。
在一种可能的实现方式中，该装置还包括分析模块；
所述分析模块用于，在所述更新模块12对包括n个目标纳米结构的纳米结构集循环执行更新操作之前，对多个不同形状的纳米结构进行性能分析，确定每个所述纳米结构的性能信息。
在一种可能的实现方式中，所述分析模块对多个不同形状的纳米结构进行性能分析，包括：
以多个同一所述纳米结构构成与所述纳米结构对应的测试超表面，并以不同入射角度 向所述测试超表面出射入射光；
将所述测试超表面在不同入射角度的入射光下的性能参数作为所述纳米结构相应的性能参数。
在一种可能的实现方式中，所述第二纳米结构与对所述主入射光具有同一调制相位的第一纳米结构以及对所述主入射光具有同一调制相位的曾经选取的其他第二纳米结构均形状不同。
在一种可能的实现方式中，所述主入射角度为0°±Δ，Δ表示在误差允许范围内的角度值。
在一种可能的实现方式中，n个所述第一纳米结构对主入射光的调制相位至少能够覆盖0至2π。
在一种可能的实现方式中，n大于或等于8。
在一种可能的实现方式中，所述第一纳米结构与所述第二纳米结构均为偏振相关结构；或者，所述第一纳米结构与所述第二纳米结构均为偏振不相关结构。
本发明实施例还提供一种超表面的设计装置，所述设计装置包括：处理器，所述处理器用于执行存储在存储器中的计算机程序，以实现上述任一方法实施例提供的超表面的设计方法。
例如，所述超表面的设计装置包括处理器和存储器；所述存储器被配置为存储计算机程序；所述处理器被配置为能够执行所述计算机程序，以使所述超表面的设计装置能够执行以下操作：
确定n个第一纳米结构，不同的所述第一纳米结构对主入射光的调制相位不同；所述主入射光为以主入射角度入射的入射光，n≥2；
对包括n个目标纳米结构的纳米结构集循环执行更新操作，直至所述纳米结构集中所有所述目标纳米结构均满足广角成像要求；最初的所述目标纳米结构为相应的所述第一纳米结构；
基于所述纳米结构集设计超表面；
其中，所述更新操作包括：
获取每个所述目标纳米结构的性能信息，所述性能信息包括在不同入射角度的入射光下所述目标纳米结构的性能参数，所述性能参数包括透射率和/或调制相位；所述目标纳米结构的性能信息用于判断所述目标纳米结构是否满足广角成像要求；
在存在不满足广角成像要求的目标纳米结构的情况下，选取新的第二纳米结构，并以所述第二纳米结构代替所述不满足广角成像要求的目标纳米结构，生成新的纳米结构集；所述第二纳米结构与所述不满足广角成像要求的目标纳米结构对所述主入射光的调制相位相同，且所述第二纳米结构与所述不满足广角成像要求的目标纳米结构具有不同的形状。
此外，本发明实施例还提供了一种电子设备，包括总线、收发器、存储器、处理器及存储在存储器上并可在处理器上运行的计算机程序，该收发器、该存储器和处理器分别通过总线相连，计算机程序被处理器执行时实现上述超表面的设计方法实施例的各个过程，且能达到相同的技术效果，为避免重复，这里不再赘述。
具体的，参见图11所示，本发明实施例还提供了一种电子设备，该电子设备包括总线 1110、处理器1120、收发器1130、总线接口1140、存储器1150和用户接口1160。
在本发明实施例中，该电子设备还包括：存储在存储器1150上并可在处理器1120上运行的计算机程序，计算机程序被处理器1120执行时实现上述超表面的设计方法实施例的各个过程。
收发器1130，用于在处理器1120的控制下接收和发送数据。
本发明实施例中，总线架构(用总线1110来代表)，总线1110可以包括任意数量互联的总线和桥，总线1110将包括由处理器1120代表的一个或多个处理器与存储器1150代表的存储器的各种电路连接在一起。
总线1110表示若干类型的总线结构中的任何一种总线结构中的一个或多个，包括存储器总线以及存储器控制器、外围总线、加速图形端口(Accelerate Graphical Port，AGP)、处理器或使用各种总线体系结构中的任意总线结构的局域总线。作为示例而非限制，这样的体系结构包括：工业标准体系结构(Industry Standard Architecture，ISA)总线、微通道体系结构(Micro Channel Architecture，MCA)总线、扩展ISA(Enhanced ISA，EISA)总线、视频电子标准协会(Video Electronics Standards Association，VESA)、外围部件互连(Peripheral Component Interconnect，PCI)总线。
处理器1120可以是一种集成电路芯片，具有信号处理能力。在实现过程中，上述方法实施例的各步骤可以通过处理器中硬件的集成逻辑电路或软件形式的指令完成。上述的处理器包括：通用处理器、中央处理器(Central Processing Unit，CPU)、网络处理器(Network Processor，NP)、数字信号处理器(Digital Signal Processor，DSP)、专用集成电路(Application Specific Integrated Circuit，ASIC)、现场可编程门阵列(Field Programmable Gate Array，FPGA)、复杂可编程逻辑器件(Complex Programmable Logic Device，CPLD)、可编程逻辑阵列(Programmable Logic Array，PLA)、微控制单元(Microcontroller Unit，MCU)或其他可编程逻辑器件、分立门、晶体管逻辑器件、分立硬件组件。可以实现或执行本发明实施例中公开的各方法、步骤及逻辑框图。例如，处理器可以是单核处理器或多核处理器，处理器可以集成于单颗芯片或位于多颗不同的芯片。
处理器1120可以是微处理器或任何常规的处理器。结合本发明实施例所公开的方法步骤可以直接由硬件译码处理器执行完成，或者由译码处理器中的硬件及软件模块组合执行完成。软件模块可以位于随机存取存储器(Random Access Memory，RAM)、闪存(Flash Memory)、只读存储器(Read-Only Memory，ROM)、可编程只读存储器(Programmable ROM，PROM)、可擦除可编程只读存储器(Erasable PROM，EPROM)、寄存器等本领域公知的可读存储介质中。所述可读存储介质位于存储器中，处理器读取存储器中的信息，结合其硬件完成上述方法的步骤。
总线1110还可以将，例如外围设备、稳压器或功率管理电路等各种其他电路连接在一起，总线接口1140在总线1110和收发器1130之间提供接口，这些都是本领域所公知的。因此，本发明实施例不再对其进行进一步描述。
收发器1130可以是一个元件，也可以是多个元件，例如多个接收器和发送器，提供用于在传输介质上与各种其他装置通信的单元。例如：收发器1130从其他设备接收外部数据，收发器1130用于将处理器1120处理后的数据发送给其他设备。取决于计算机系统的 性质，还可以提供用户接口1160，例如：触摸屏、物理键盘、显示器、鼠标、扬声器、麦克风、轨迹球、操纵杆、触控笔。
应理解，在本发明实施例中，存储器1150可进一步包括相对于处理器1120远程设置的存储器，这些远程设置的存储器可以通过网络连接至服务器。上述网络的一个或多个部分可以是自组织网络(ad hoc network)、内联网(intranet)、外联网(extranet)、虚拟专用网(VPN)、局域网(LAN)、无线局域网(WLAN)、广域网(WAN)、无线广域网(WWAN)、城域网(MAN)、互联网(Internet)、公共交换电话网(PSTN)、普通老式电话业务网(POTS)、蜂窝电话网、无线网络、无线保真(Wi-Fi)网络以及两个或更多个上述网络的组合。例如，蜂窝电话网和无线网络可以是全球移动通信(GSM)系统、码分多址(CDMA)系统、全球微波互联接入(WiMAX)系统、通用分组无线业务(GPRS)系统、宽带码分多址(WCDMA)系统、长期演进(LTE)系统、LTE频分双工(FDD)系统、LTE时分双工(TDD)系统、先进长期演进(LTE-A)系统、通用移动通信(UMTS)系统、增强移动宽带(Enhance Mobile Broadband，eMBB)系统、海量机器类通信(massive Machine Type of Communication，mMTC)系统、超可靠低时延通信(Ultra Reliable Low Latency Communications，uRLLC)系统等。
应理解，本发明实施例中的存储器1150可以是易失性存储器或非易失性存储器，或可包括易失性存储器和非易失性存储器两者。其中，非易失性存储器包括：只读存储器(Read-Only Memory，ROM)、可编程只读存储器(Programmable ROM，PROM)、可擦除可编程只读存储器(Erasable PROM，EPROM)、电可擦除可编程只读存储器(Electrically EPROM，EEPROM)或闪存(Flash Memory)。
易失性存储器包括：随机存取存储器(Random Access Memory，RAM)，其用作外部高速缓存。通过示例性但不是限制性说明，许多形式的RAM可用，例如：静态随机存取存储器(Static RAM，SRAM)、动态随机存取存储器(Dynamic RAM，DRAM)、同步动态随机存取存储器(Synchronous DRAM，SDRAM)、双倍数据速率同步动态随机存取存储器(Double Data Rate SDRAM，DDRSDRAM)、增强型同步动态随机存取存储器(Enhanced SDRAM，ESDRAM)、同步连接动态随机存取存储器(Synchlink DRAM，SLDRAM)和直接内存总线随机存取存储器(Direct Rambus RAM，DRRAM)。本发明实施例描述的电子设备的存储器1150包括但不限于上述和任意其他适合类型的存储器。
在本发明实施例中，存储器1150存储了操作系统1151和应用程序1152的如下元素：可执行模块、数据结构，或者其子集，或者其扩展集。
具体而言，操作系统1151包含各种系统程序，例如：框架层、核心库层、驱动层等，用于实现各种基础业务以及处理基于硬件的任务。应用程序1152包含各种应用程序，例如：媒体播放器(Media Player)、浏览器(Browser)，用于实现各种应用业务。实现本发明实施例方法的程序可以包含在应用程序1152中。应用程序1152包括：小程序、对象、组件、逻辑、数据结构以及其他执行特定任务或实现特定抽象数据类型的计算机系统可执行指令。
此外，本发明实施例还提供了一种计算机可读存储介质，其上存储有计算机程序，所述计算机程序被处理器执行时实现上述超表面的设计方法实施例的各个过程，且能达到相 同的技术效果，为避免重复，这里不再赘述。
计算机可读存储介质包括：永久性和非永久性、可移动和非可移动媒体，是可以保留和存储供指令执行设备所使用指令的有形设备。计算机可读存储介质包括：电子存储设备、磁存储设备、光存储设备、电磁存储设备、半导体存储设备以及上述任意合适的组合。计算机可读存储介质包括：相变内存(PRAM)、静态随机存取存储器(SRAM)、动态随机存取存储器(DRAM)、其他类型的随机存取存储器(RAM)、只读存储器(ROM)、非易失性随机存取存储器(NVRAM)、电可擦除可编程只读存储器(EEPROM)、快闪记忆体或其他内存技术、光盘只读存储器(CD-ROM)、数字多功能光盘(DVD)或其他光学存储、磁盒式磁带存储、磁带磁盘存储或其他磁性存储设备、记忆棒、机械编码装置(例如在其上记录有指令的凹槽中的穿孔卡或凸起结构)或任何其他非传输介质、可用于存储可以被计算设备访问的信息。按照本发明实施例中的界定，计算机可读存储介质不包括暂时信号本身，例如无线电波或其他自由传播的电磁波、通过波导或其他传输介质传播的电磁波(例如穿过光纤电缆的光脉冲)或通过导线传输的电信号。
在本申请所提供的几个实施例中，应该理解到，所披露的装置、电子设备和方法，可以通过其他的方式实现。例如，以上描述的装置实施例仅仅是示意性的，例如，所述模块或单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或可以集成到另一个系统，或一些特征可以忽略，或不执行。另外，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口、装置或单元的间接耦合或通信连接，也可以是电的、机械的或其他的形式连接。
所述作为分离部件说明的单元可以是或也可以不是物理上分开的，作为单元显示的部件可以是或也可以不是物理单元，既可以位于一个位置，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或全部单元来解决本发明实施例方案要解决的问题。
另外，在本发明各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以是两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
所述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读存储介质中。基于这样的理解，本发明实施例的技术方案本质上或者说对现有技术作出贡献的部分，或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(包括：个人计算机、服务器、数据中心或其他网络设备)执行本发明各个实施例所述方法的全部或部分步骤。而上述存储介质包括如前述所列举的各种可以存储程序代码的介质。
在本发明实施例的描述中，所属技术领域的技术人员应当知道，本发明实施例可以实现为方法、装置、电子设备及计算机可读存储介质。因此，本发明实施例可以具体实现为以下形式：完全的硬件、完全的软件(包括固件、驻留软件、微代码等)、硬件和软件结合的形式。此外，在一些实施例中，本发明实施例还可以实现为在一个或多个计算机可读存储介质中的计算机程序产品的形式，该计算机可读存储介质中包含计算机程序代码。
上述计算机可读存储介质可以采用一个或多个计算机可读存储介质的任意组合。计算机可读存储介质包括：电、磁、光、电磁、红外或半导体的系统、装置或器件，或者以上任意的组合。计算机可读存储介质更具体的例子包括：便携式计算机磁盘、硬盘、随机存取存储器(RAM)、只读存储器(ROM)、可擦除可编程只读存储器(EPROM)、闪存(Flash Memory)、光纤、光盘只读存储器(CD-ROM)、光存储器件、磁存储器件或以上任意组合。在本发明实施例中，计算机可读存储介质可以是任意包含或存储程序的有形介质，该程序可以被指令执行系统、装置、器件使用或与其结合使用。
上述计算机可读存储介质包含的计算机程序代码可以用任意适当的介质传输，包括：无线、电线、光缆、射频(Radio Frequency，RF)或者以上任意合适的组合。
可以以汇编指令、指令集架构(ISA)指令、机器指令、机器相关指令、微代码、固件指令、状态设置数据、集成电路配置数据或以一种或多种程序设计语言或其组合来编写用于执行本发明实施例操作的计算机程序代码，所述程序设计语言包括面向对象的程序设计语言，例如：Java、Smalltalk、C++，还包括常规的过程式程序设计语言，例如：C语言或类似的程序设计语言。计算机程序代码可以完全的在用户计算机上执行、部分的在用户计算机上执行、作为一个独立的软件包执行、部分在用户计算机上部分在远程计算机上执行以及完全在远程计算机或服务器上执行。在涉及远程计算机的情形中，远程计算机可以通过任意种类的网络，包括：局域网(LAN)或广域网(WAN)，可以连接到用户计算机，也可以连接到外部计算机。
本发明实施例通过流程图和/或方框图描述所提供的方法、装置、电子设备。
应当理解，流程图和/或方框图的每个方框以及流程图和/或方框图中各方框的组合，都可以由计算机可读程序指令实现。这些计算机可读程序指令可以提供给通用计算机、专用计算机或其他可编程数据处理装置的处理器，从而生产出一种机器，这些计算机可读程序指令通过计算机或其他可编程数据处理装置执行，产生了实现流程图和/或方框图中的方框规定的功能/操作的装置。
也可以将这些计算机可读程序指令存储在能使得计算机或其他可编程数据处理装置以特定方式工作的计算机可读存储介质中。这样，存储在计算机可读存储介质中的指令就产生出一个包括实现流程图和/或方框图中的方框规定的功能/操作的指令装置产品。
也可以将计算机可读程序指令加载到计算机、其他可编程数据处理装置或其他设备上，使得在计算机、其他可编程数据处理装置或其他设备上执行一系列操作步骤，以产生计算机实现的过程，从而使得在计算机或其他可编程数据处理装置上执行的指令能够提供实现流程图和/或方框图中的方框规定的功能/操作的过程。
以上所述，仅为本发明实施例的具体实施方式，但本发明实施例的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明实施例披露的技术范围内，可轻易想到变化或替换，都应涵盖在本发明实施例的保护范围之内。因此，本发明实施例的保护范围应以权利要求的保护范围为准。

Claims (20)

  1. 一种超表面的设计方法，其特征在于，包括：
    确定n个第一纳米结构，不同的所述第一纳米结构对主入射光的调制相位不同；所述主入射光为以主入射角度入射的入射光，n≥2；
    对包括n个目标纳米结构的纳米结构集循环执行更新操作，直至所述纳米结构集中所有所述目标纳米结构均满足广角成像要求；最初的所述目标纳米结构为相应的所述第一纳米结构；
    基于所述纳米结构集设计超表面；
    其中，所述更新操作包括：
    获取每个所述目标纳米结构的性能信息，所述性能信息包括在不同入射角度的入射光下所述目标纳米结构的性能参数，所述性能参数包括透射率和/或调制相位；所述目标纳米结构的性能信息用于判断所述目标纳米结构是否满足广角成像要求；
    在存在不满足广角成像要求的目标纳米结构的情况下，选取新的第二纳米结构，并以所述第二纳米结构代替所述不满足广角成像要求的目标纳米结构，生成新的纳米结构集；所述第二纳米结构与所述不满足广角成像要求的目标纳米结构对所述主入射光的调制相位相同，且所述第二纳米结构与所述不满足广角成像要求的目标纳米结构具有不同的形状。
  2. 根据权利要求1所述的方法，其特征在于，在所述性能参数包括透射率的情况下，所述广角成像要求包括广角成像透射率要求；所述目标纳米结构在不同入射角度的入射光下的透射率越大，越能够满足所述广角成像透射率要求。
  3. 根据权利要求2所述的方法，其特征在于，所述更新操作还包括：
    确定每个所述入射角度对应的第一平均透射率，所述第一平均透射率为多个所述目标纳米结构在所述入射角度的入射光下的透射率的加权平均值；
    在至少一个所述第一平均透射率低于第一预设透射率阈值的情况下，确定至少一个目标纳米结构不满足所述广角成像透射率要求。
  4. 根据权利要求3所述的方法，其特征在于，所述确定每个所述入射角度对应的第一平均透射率，包括：
    确定每个所述目标纳米结构的权重，根据所述权重对多个所述目标纳米结构在所述入射角度的入射光下的透射率进行加权处理，得到所述入射角度对应的第一平均透射率；不同的所述目标纳米结构的权重相同，或者，所述目标纳米结构的权重与所述超表面中与所述目标纳米结构对应同一调制相位的纳米结构的数量之间为正相关关系；
    所述第一平均透射率满足：
    其中，wi表示第i个目标纳米结构的权重，ti,j表示第i个目标纳米结构在第j个入射 角度的入射光下的透射率，表示第j个入射角度对应的第一平均透射率。
  5. 根据权利要求3所述的方法，其特征在于，所述确定至少一个目标纳米结构不满足所述广角成像透射率要求，包括：
    将具有最低透射率或具有最低第二平均透射率的目标纳米结构作为不满足所述广角成像透射率要求的目标纳米结构；所述第二平均透射率为所述目标纳米结构在多个所述入射角度的入射光下的透射率的平均值。
  6. 根据权利要求3所述的方法，其特征在于，所述更新操作还包括：
    在所有所述第一平均透射率均不低于第一预设透射率阈值的情况下，确定所有所述目标纳米结构均满足所述广角成像透射率要求；
    或者，在所有所述第一平均透射率均不低于第一预设透射率阈值、且所述主入射角度对应的第一平均透射率不低于第二预设透射率阈值的情况下，确定所有所述目标纳米结构均满足所述广角成像透射率要求；所述第二预设透射率阈值大于所述第一预设透射率阈值。
  7. 根据权利要求2所述的方法，其特征在于，所述更新操作还包括：
    判断每个所述目标纳米结构的透射参数是否低于第三预设透射率阈值；所述目标纳米结构的透射参数包括：所述目标纳米结构的透射率中的最小值，或者，所述目标纳米结构的第二平均透射率；所述第二平均透射率为所述目标纳米结构在多个所述入射角度的入射光下的透射率的平均值；
    在存在透射参数低于第三预设透射率阈值的目标纳米结构的情况下，将具有最低透射参数的目标纳米结构作为不满足所述广角成像透射率要求的目标纳米结构。
  8. 根据权利要求1-7任意一项所述的方法，其特征在于，在所述性能参数包括调制相位的情况下，所述广角成像要求包括广角成像相位要求；所述目标纳米结构的相位梯度越小，越能够满足所述广角成像相位要求；其中，所述目标纳米结构的相位梯度用于表示所述目标纳米结构的调制相位的变化程度。
  9. 根据权利要求8所述的方法，其特征在于，所述更新操作还包括：
    确定每个所述目标纳米结构的相位梯度，所述目标纳米结构的相位梯度包括：所述目标纳米结构与相邻的其他目标纳米结构之间的调制相位之差随入射角度变化所具有的变化程度，和/或，所述目标纳米结构的调制相位随入射角度变化所具有的变化程度；
    在所述目标纳米结构的相位梯度高于相应的预设梯度阈值的情况下，确定相位梯度高于预设梯度阈值的目标纳米结构不满足所述广角成像相位要求。
  10. 根据权利要求9所述的方法，其特征在于，所述更新操作还包括：
    确定所述目标纳米结构在第j个入射角度处的相位梯度与所述目标纳米结构在所述主入射角度处的相位梯度之间的变化比，且所述变化比满足：
    其中，表示第i个目标纳米结构在第j个入射角度处的相位梯度，表示第i 个目标纳米结构在所述主入射角度处的相位梯度，Ri,j表示第i个目标纳米结构在第j个入射角度处的变化比；
    在所述变化比超过预设比值的情况下，确定所述目标纳米结构的相位梯度高于相应的预设梯度阈值。
  11. 根据权利要求1所述的方法，其特征在于，在所述对包括n个目标纳米结构的纳米结构集循环执行更新操作之前，还包括：
    对多个不同形状的纳米结构进行性能分析，确定每个所述纳米结构的性能信息。
  12. 根据权利要求11所述的方法，其特征在于，所述对多个不同形状的纳米结构进行性能分析，包括：
    以多个同一所述纳米结构构成与所述纳米结构对应的测试超表面，并以不同入射角度向所述测试超表面出射入射光；
    将所述测试超表面在不同入射角度的入射光下的性能参数作为所述纳米结构相应的性能参数。
  13. 根据权利要求1所述的方法，其特征在于，所述第二纳米结构与对所述主入射光具有同一调制相位的第一纳米结构以及对所述主入射光具有同一调制相位的曾经选取的其他第二纳米结构均形状不同。
  14. 根据权利要求1所述的方法，其特征在于，所述主入射角度为0°±Δ，Δ表示在误差允许范围内的角度值。
  15. 根据权利要求1所述的方法，其特征在于，n个所述第一纳米结构对主入射光的调制相位至少能够覆盖0至2π。
  16. 根据权利要求15所述的方法，其特征在于，n大于或等于8。
  17. 根据权利要求1所述的方法，其特征在于，所述第一纳米结构与所述第二纳米结构均为偏振相关结构；或者，所述第一纳米结构与所述第二纳米结构均为偏振不相关结构。
  18. 一种超表面的设计装置，其特征在于，包括：
    初始模块，用于确定n个第一纳米结构，不同的所述第一纳米结构对主入射光的调制相位不同；所述主入射光为以主入射角度入射的入射光，n≥2；
    更新模块，用于对包括n个目标纳米结构的纳米结构集循环执行更新操作，直至所述纳米结构集中所有所述目标纳米结构均满足广角成像要求；最初的所述目标纳米结构为相应的所述第一纳米结构；
    设计模块，用于基于所述纳米结构集设计超表面；
    其中，所述更新模块包括获取单元和更新单元；
    所述获取单元用于，获取每个所述目标纳米结构的性能信息，所述性能信息包括在不同入射角度的入射光下所述目标纳米结构的性能参数，所述性能参数包括透射率和/或调制相位；所述目标纳米结构的性能信息用于判断所述目标纳米结构是否满足广角成像要求；
    所述更新单元用于，在存在不满足广角成像要求的目标纳米结构的情况下，选取新的第二纳米结构，并以所述第二纳米结构代替所述不满足广角成像要求的目标纳米结构，生 成新的纳米结构集；所述第二纳米结构与所述不满足广角成像要求的目标纳米结构对所述主入射光的调制相位相同，且所述第二纳米结构与所述不满足广角成像要求的目标纳米结构具有不同的形状。
  19. 一种电子设备，包括总线、收发器、存储器、处理器及存储在所述存储器上并可在所述处理器上运行的计算机程序，所述收发器、所述存储器和所述处理器通过所述总线相连，其特征在于，所述计算机程序被所述处理器执行时实现如权利要求1至17中任一项所述的超表面的设计方法中的步骤。
  20. 一种计算机可读存储介质，其上存储有计算机程序，其特征在于，所述计算机程序被处理器执行时实现如权利要求1至17中任一项所述的超表面的设计方法中的步骤。
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