KR20210110150A - Meta lens and electronic apparatus including the same - Google Patents

Abstract

A disclosed meta-optical device represents a predetermined target phase delay profile for incident light of a predetermined wavelength band, comprising: a first layer including a plurality of first nanostructures and a first surrounding material surrounding the first nanostructures; and a second layer disposed on the first layer and including a plurality of second nanostructures and a second surrounding material surrounding the second nanostructures, wherein the first layer and the second layer include regions in which signs of effective refractive index change rates in a predetermined first direction are opposite to each other. By controlling the change in refractive index and dispersion of each layer, it is possible to implement a phase delay profile with little discontinuity. The meta-optical device that operates over a broad band and exhibits high efficiency is provided.

Description

Meta optical element and electronic device including same {Meta lens and electronic apparatus including the same}

The disclosed embodiments relate to a meta optical device and an electronic device including the same.

A plate-type diffractive element utilizing a meta-structure can exhibit various optical effects that cannot be realized by conventional refractive elements and can implement a thin optical system, and thus interest in many fields is increasing.

The meta-structure has a nanostructure in which a number smaller than the wavelength of the incident light is applied to a shape, a period, etc., and a nanostructure such that a phase delay profile set for each position is satisfied for a light of a desired wavelength band in order to realize a desired optical performance. design the structure. When a discontinuity appears in the phase delay profile, diffraction of light occurs in an unintended direction and the light efficiency is lowered.

A meta-optical device that operates over a wide band and exhibits high efficiency is provided.

An electronic device using a meta-optical device is provided.

According to one type, exhibiting a predetermined target phase retardation profile with respect to incident light of a predetermined wavelength band, the first layer comprising a plurality of first nanostructures and a first surrounding material surrounding them; a second layer disposed on the first layer, the second layer including a plurality of second nanostructures and a second surrounding material surrounding them; There is provided a meta-optical device including regions having opposite signs of effective refractive index change according to .

The first layer and the second layer may have different ratios of dispersion change to effective refractive index change in the first direction.

The target phase delay profile may have zero dispersion with respect to a wavelength of the predetermined wavelength band.

The phase delay profile represented by the first layer and the target phase delay profile may have the same sign of a change rate in the first direction.

A ratio of a variance change rate to a change in the effective refractive index of the second layer in the first direction may be greater than a ratio of a variance change in the effective refractive index change in the first layer in the first direction.

The material included in the second layer may have greater dispersion than the material included in the first layer.

The phase delay profile represented by the first layer and the phase delay profile represented by the second layer may have opposite signs of change rates in the first direction.

The target phase delay profile may be a continuous function with respect to the first direction in the predetermined wavelength band.

The first nanostructure and the second nanostructure may have a columnar shape.

A ratio of a height to a width of the first nanostructure and the second nanostructure may be greater than 2.

The height of the first nanostructure and the second nanostructure may be greater than a central wavelength of the predetermined wavelength band.

The first nanostructure may have a refractive index higher than that of the first surrounding material, and the second nanostructure may have a higher refractive index than that of the second surrounding material.

The widths of the first nanostructures and the second nanostructures may be opposite to each other in a direction away from the center of the meta-optical device.

The first nanostructure may have a refractive index lower than that of the first surrounding material, and the second nanostructure may have a higher refractive index than that of the second surrounding material.

The first nanostructures and the second nanostructures may have the same tendency to change in width in one direction away from the center of the meta-optical device.

The first nanostructure may have a shape including an inner pillar and a shell pillar surrounding the inner pillar. ,

A refractive index of the inner pillar may be lower than a refractive index of the shell pillar.

A refractive index of the shell pillar may be higher than a refractive index of the first surrounding material.

The second nanostructure may have a higher refractive index than that of the second surrounding material.

The width of the first nanostructures and the second nanostructures may be opposite to each other in a direction away from the center of the meta-optical device.

The second nanostructure may have a lower refractive index than that of the second surrounding material.

The first nanostructures and the second nanostructures may have the same tendency to change in width in one direction away from the center of the meta-optical device.

The first nanostructure may have a hole shape surrounded by the first surrounding material.

The second nanostructure may have a higher refractive index than that of the second surrounding material.

The holes of the first nanostructures and the second nanostructures may have the same tendency to change in width in one direction along a direction away from the center of the meta-optical device.

The second nanostructure may have a lower refractive index than that of the second surrounding material.

The tendency of the width of the hole of the first nanostructures and the second nanostructures to change in one direction away from the center of the meta-optical device may be opposite to each other.

The meta-optical device may further include a substrate supporting the first layer and the second layer.

The meta-optical device may further include a spacer layer provided between the first layer and the second layer.

In the target phase delay profile, dispersion with respect to a wavelength of the predetermined wavelength band may be less than zero.

In the target phase delay profile, dispersion with respect to a wavelength of the predetermined wavelength band may be greater than zero.

The meta optical element may be a lens.

The meta optical element may be a beam deflector.

The meta optical element may be a beam shaper.

The predetermined wavelength band may be in a wavelength range of 400 nm to 700 m.

A ratio of a length in the first direction of the region to a total length in the first direction of the meta-optical device may be 80% or more.

The diffraction efficiency for light of the predetermined wavelength band may be 0.8 or more.

According to one type, an imaging lens assembly including one or more refractive lenses and any one of the above-described meta-optical elements; and an image sensor that converts an optical image formed by the imaging lens assembly into an electrical signal.

According to one type, a light source; any one of the above-described meta-optical elements that modulate light from the light source and transmit it to an object; and a photodetector configured to sense light from the object.

The above-described meta-optical device can implement a phase delay profile with almost no discontinuity by utilizing nanostructures arranged in a multi-layered structure and adjusting a change in refractive index and a change in dispersion of each layer.

The above-described meta-optical device may exhibit high diffraction efficiency with respect to light of a wide wavelength band.

The above-described meta-optical device may be utilized as a lens, a beam deflector, a beam shaper, and the like, and may be employed in various electronic devices using them.

1 is a conceptual diagram schematically showing a schematic configuration and function of a meta-optical device according to an embodiment.
2 is a plan view showing a schematic configuration of a plurality of layers constituting a meta-optical device according to an embodiment.
3 is a graph exemplarily showing the effective refractive index and dispersion for each wavelength and position of a phase delay layer provided in the meta-optical device according to the embodiment.
4 is a graph exemplarily showing the effective refractive index and dispersion for each wavelength and position of a dispersion control layer provided in the meta-optical device according to the embodiment.
5 is a graph exemplarily showing a phase delay profile for each wavelength by a meta-optical device according to an embodiment.
6 is a cross-sectional view showing a schematic structure of a meta-optical device according to an embodiment.
7A and 7B are perspective views illustrating an exemplary shape of a nanostructure that may be employed in a meta-optical device according to an embodiment.
8 is a cross-sectional view showing a schematic structure of a meta-optical device according to another embodiment.
9 is a cross-sectional view showing a schematic structure of a meta-optical device according to another embodiment.
10A and 10B are plan views illustrating exemplary shapes of a first nanostructure that may be employed in the first layer of the meta-optical device of FIG. 9 .
11 is a graph showing the phase delay according to the detailed dimensions of the first nanostructure constituting the first layer of the meta-optical device of FIG. 9 .
12 and 13 are graphs showing the diffraction efficiency of the meta-optical device of FIG. 9 .
14 is a cross-sectional view showing a schematic structure of a meta-optical device according to another embodiment.
15 is a cross-sectional view showing a schematic structure of a meta-optical device according to another embodiment.
16 is a graph showing the phase delay according to the detailed dimensions of the first nanostructure constituting the first layer of the meta-optical device of FIG. 15 .
17 is a graph showing the diffraction efficiency of the meta-optical device of FIG. 15 .
18 is a cross-sectional view showing a schematic structure of a meta-optical device according to another embodiment.
19 is a graph exemplarily showing a phase delay profile for each wavelength by an optical meta-optical device according to another embodiment.
20 is a graph exemplarily showing a phase delay profile for each wavelength by an optical meta-optical device according to another embodiment.
21 is a block diagram illustrating a schematic configuration of an electronic device according to an embodiment.
22 is a block diagram showing a schematic configuration of a camera module included in the electronic device of FIG. 21 .
23 is a block diagram illustrating a schematic configuration of a 3D sensor provided in the electronic device of FIG. 21 .

Hereinafter, an embodiment will be described in detail with reference to the accompanying drawings. The described embodiments are merely exemplary, and various modifications are possible from these embodiments. In the following drawings, the same reference numerals refer to the same components, and the size of each component in the drawings may be exaggerated for clarity and convenience of description.

Hereinafter, what is described as "upper" or "upper" may include not only those directly above in contact, but also those above in non-contact.

Terms such as first, second, etc. may be used to describe various elements, but are used only for the purpose of distinguishing one element from other elements. These terms do not limit the difference in the material or structure of the components.

The singular expression includes the plural expression unless the context clearly dictates otherwise. In addition, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.

In addition, terms such as “…unit” and “module” described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software, or a combination of hardware and software. .

The use of the term “above” and similar referential terms may be used in both the singular and the plural.

The steps constituting the method may be performed in any suitable order, unless expressly stated that they must be performed in the order described. In addition, the use of all exemplary terms (eg, etc.) is merely for describing the technical idea in detail, and unless limited by the claims, the scope of rights is not limited by these terms.

1 is a conceptual diagram schematically showing a schematic configuration and function of a meta-optical device according to an embodiment. 2 is a plan view showing a schematic configuration of a plurality of layers constituting a meta-optical device according to an embodiment.

The meta-optical element 100 is a diffractive element using a nanostructure having a sub-wavelength shape dimension, and a detailed structure is set so as to exhibit a predetermined target phase delay profile with respect to incident light of a predetermined wavelength band. Here, the sub-wavelength means a value smaller than _{the central wavelength (λ 0 ) of the predetermined wavelength band.}

The incident light L is emitted as _{modulated light L m} whose phase is modulated for each position after passing through the meta optical element 100 . When light is incident on the meta-optical element 100 and passes through the meta-optical element 100 , a refractive index distribution is met by an arrangement of a plurality of nanostructures NS1 and NS2 having a refractive index different from that of the surrounding material. The shape of the wavefront connecting points with the same phase in the light propagation path is different before and after undergoing the refractive index distribution by the array of nanostructures (NS1) and (NS2), which is expressed as a phase delay. The degree of phase retardation depends on each position as a variable in the refractive index distribution. The degree of the phase delay varies depending on the x and y coordinates on a plane perpendicular to the traveling direction (Z direction) of the light at a position immediately after the incident light L incident in the Z direction passes through the meta optical element 100 . As such, the phase of light after passing through the meta-optical element 100 represents a phase different from that at the time of incidence. The target phase delay profile φ _t represented by the modulated light L _m represents a phase relative to the phase of the incident light L . The target phase delay profile (φ _t ) represents a phase delay according to each position after passing through the meta optical element 100 , while this phase delay also depends on the wavelength (λ) of the incident light. The target phase retardation profile φ _t is thus expressed as a function of position and wavelength φ _t (r, λ).

The optical performance of the meta optical element 100, for example, a lens, a mirror, a beam deflector, or a function as a beam shaper is determined according to the target phase delay profile φ _{t .}

The meta-optical device 100 includes a first layer 120 and a second layer 160, and the first layer 120 has a structure based on the first nanostructure NS1 and serves as a phase delay layer. , the second layer 160 has a structure based on the second nanostructure NS2 and serves as a dispersion control layer.

In the first layer 120 serving as a phase delay layer and the second layer 160 serving as a dispersion control layer, signs of effective refractive index change according to positions may be opposite to each other. For example, when the material and shape of the first nanostructure NS1 are set such that the effective refractive index of the first layer 120 is gradually increased along the first predetermined direction, the second layer NS2 is the second layer NS2. The material and shape of the second nanostructure NS2 may be set such that the effective refractive index gradually decreases along one direction.

These multiple layer structure, but the implementation of meta-optical element 100, the target phase delay profile (φ _t) is desired to improve the light efficiency by minimizing the phase discontinuity in accordance with the location of the target phase delay profile (φ _t).

In general optical materials, dispersion has a negative value in the visible wavelength band, and as the refractive index increases, the size of dispersion tends to increase. difficult to implement For example, the phase delay profile of the first layer 120 and the phase delay profile of the second layer 160 may have discontinuities. The phase discontinuity may mainly appear at the boundary of the plurality of regions 2π zone (R ₁ , .. R _k , ..R _{N ) illustrated in FIG. 2 .} However, the meta-optical device 100 of the embodiment subdivides the functions of the first layer 120 and the second layer 160 in terms of refractive index change control and dispersion change control, and is a unit in which various types of materials and shapes are combined. By deriving a structure optimized for each position of the component UE, a phase delay profile with almost no discontinuity may be exhibited in a configuration in which the first layer 120 and the second layer 160 are combined.

The meta-optical device 100 according to the embodiment includes _{a layer showing a phase delay profile of the same tendency as the target phase delay profile (φ t} ), and a layer showing a phase delay profile opposite to this, that is, the first The layer 120 and the second layer 160 may exhibit different phase retardation profiles, respectively. In the first layer 120 serving as a phase delay layer, the shape and arrangement of the first nanostructures NS1 may be set to exhibit a phase delay profile of the same tendency as the _{target phase delay profile φ t .} The second layer 160 serving as a dispersion control layer _{exhibits a phase retardation profile of a different tendency from the target phase retardation profile (φ t} ), but the second nanostructure so as to have a main function to control refractive index dispersion according to wavelength The shape and arrangement of (NS2) can be set.

Here, the phase delay profile of the first layer 120 is a phase when light is incident on the first nanostructures NS1 at a position immediately after passing through the nanostructures NS1 of the first layer 120 . It means the relative phase distribution of In addition, the phase delay profile of the second layer 160 is a phase when light is incident on the second nanostructures NS2 at a position immediately after passing through the nanostructures NS2 of the second layer 160 . It means the relative phase distribution of

The positions of the first layer 120 and the second layer 160 may be interchanged. In FIG. 1 , the incident light L is illustrated as being incident on the second layer 160 after passing through the first layer 120 , but this is exemplary and is not limited thereto. In relation to the incident light L, the order of the first layer 120 and the second layer 160 may be reversed. This is the same for all examples below. In addition, it is described for convenience that the first layer 120 functions as a phase delay layer and the second layer 160 functions as a dispersion control layer. It is a structure, and the function is not limited according to the name.

The shapes of the first nanostructures NS1 and the second nanostructures NS2 provided in each layer may be determined as a function of the positions of the plurality of first nanostructures NS1 and the second nanostructures NS2, respectively. . For example, the first nanostructure NS1 provided in the first layer 120 may be determined as a function of coordinates (x,y) on the surface S1 on which the first nanostructure NS1 is placed. These coordinates (x, y) can be determined as a function of the distance from the point where the plane S1 meets the central axis C of the meta-optical element 100 and the angle θ between the radius vector and the x-axis of the corresponding position. have. The second nanostructure NS2 provided in the second layer 160 may be determined as a function of coordinates (x,y) on the surface S2 on which the second nanostructure NS2 is placed. These coordinates (x, y) are to be determined as a function of the distance from the point where the plane S2 meets the central axis C of the meta-optical element 100 and the angle θ between the radius vector of the position and the x-axis. can The first nanostructure NS1 provided in the first layer 120 and the second nanostructure NS2 provided in the second layer 160 are polar symmetric functions that depend only on the distance from the center, respectively. may be determined as

In an embodiment, the shape and arrangement of the first nanostructures NS1 and the second nanostructures NS2 are the effective refractive index changes described above along the radial direction away from the center defined on the surfaces S1 and S2 on which they are placed, A phase delay profile may be set to be implemented.

The shapes of the first nanostructure NS1 and the second nanostructure NS2 may follow a predetermined rule, and the first layer 120 and the second layer 160 constituting the meta-optical device 100 may conform to these rules. can be divided according to The regions of the first layer 120 and the second layer 160 are, as exemplarily shown in FIG. 2 , a central circular region and a plurality of annular regions surrounding it (R ₁ , R ₂ , ,,R _N ) can be partitioned into The nanostructures NS1 and NS2 in the same area in each layer may be arranged in the same order.

The regions R ₁ , .. R _k , and ..R _N are regions exhibiting a phase delay within a predetermined range, and the phase modulation ranges of _{the second region R 2} to the Nth region R _{N may be the same.} can The phase modulation range may be 2π radians. The phase modulation range of the first region (R ₁ ) may be 2π radians (radian), or may be smaller than this, but the first region (R ₁ ) to the N- _{th region (R N} ) are all generally referred to as 2π zones. have.

The function of each region, the number (N) or width (W ₁ ,.. W _k ,.. W _N ) of each region may be a major variable in the performance of the meta-optical device 100 .

In order for the meta-optical device 100 to function as a lens, the rules in the region are set so that the width of each region is not constant and the direction of diffracting the incident light in each region is slightly different. The number of regions is related to the magnitude (absolute value) of the refractive power, and the sign of the refractive power may be determined according to a rule within each region. For example, positive refractive power may be implemented by an arrangement of a rule in which the size of the nanostructures NS1 and NS2 decreases along the radial direction in each region, and the nanostructures NS1 and NS2 along the radial direction ( Negative refractive power may be implemented by the arrangement of the rule in which the size of NS1) (NS2) increases.

Meta-optical element 100, the beam deflector in order to function as a (beam deflector), the width of the respective areas (R _1, R _2, R ,, _N) (W _1, W .. _k, .. W _N)) is A rule within the region may be set so as to be constant and diffract the incident light L in a predetermined constant direction in each region.

The meta optical element 100 may function as a beam shaper having an arbitrary distribution for each position in addition to a lens or a beam deflector. In order for the above-described functions to appear efficiently within a desired wavelength band through the meta-optical device 100 , discontinuity according to position in the target phase delay profile related to the function should not appear as much as possible. When the target phase retardation profile has phase discontinuity, a portion of the light passing through the meta-optical element 100 is diffracted in a direction other than the desired diffraction direction, and thus the diffraction efficiency is lowered. The diffraction efficiency may be expressed as an energy ratio of light diffracted in an intended direction among the light transmitted through the meta-optical device 100 . The meta-optical device 100 of the embodiment has a first layer 120 and a second layer 160 such that the diffraction efficiency is 0.8 or more in a desired wavelength band, for example, the diffraction efficiency is 0.8 or more in a broadband of 400 nm to 700 nm. ), the shape, arrangement, and material of the first nanostructure NS1 and the second nanostructure NS2 may be set.

The first nanostructure NS1 and the second nanostructure NS2 are made of a material having a refractive index difference from that of a surrounding material. For example, it may have a high refractive index with a difference of 0.5 or more with respect to the refractive index of the surrounding material, or a low refractive index with a difference of 0.5 or more with respect to the refractive index of the surrounding material. One of the first nanostructures NS1 and the second nanostructures NS2 may have a refractive index higher than that of the surrounding material, and the other may have a lower refractive index than the surrounding material.

When the first nanostructure NS1 or the second nanostructure NS2 is made of a material having a higher refractive index than the surrounding material, the first nanostructure NS1 or the second nanostructure NS2 is c-Si, p-Si , a-Si III-V compound semiconductors (GaAs, GaP, GaN, GaAs, etc.), SiC, TiO ₂ , SiN, or a combination thereof, and the surrounding material of low refractive index is SU-8, PMMA polymeric materials such as SiO ₂ , or SOG.

When the first nanostructure (NS1) or the second nanostructure (NS2) is made of a material having a lower refractive index than the surrounding material, the first nanostructure (NS1), or the second nanostructure (NS2) is SiO ₂ , or air The high refractive index surrounding material is at least one of c-Si, p-Si, a-Si III-V compound semiconductors (GaAs, GaP, GaN, GaAs, etc.), SiC, TiO ₂ , SiN, or a combination thereof. may contain one.

3 is a graph exemplarily showing effective refractive index and dispersion for each wavelength and position of the phase delay layer provided in the meta-optical device of FIG. 1 , and FIG. 4 is a wavelength of the dispersion control layer provided in the meta-optical device of FIG. 1 It is a graph showing the effective refractive index and dispersion for each star and position by way of example.

The effective refractive index is a concept assuming that the unit components of the meta optical element 100 can be viewed as a uniform medium. When media having different refractive indices are included in the unit component, the concept of effective refractive index may imply distribution of different media.

The refractive index dispersion refers to the degree (∂n/∂λ) in which the refractive index appears differently depending on the wavelength, and in a structure including media having different refractive indices, it refers to the dispersion of the effective refractive index. It may be referred to simply as dispersion hereinafter.

3 and 4 together, in the phase delay layer and the dispersion control layer, the change tendency of the effective refractive index along the first predetermined direction is opposite. In the graph, the effective refractive index change trend is shown along the radial direction (r). The phase delay layer may exhibit an effective refractive index change with location that tends to be the same as the target phase delay profile.

According to this effective refractive index change tendency, the phase delay profile and the target phase delay profile represented by the phase delay layer have the same sign of the change rate according to the position, and the phase delay profile and the target phase delay profile indicated by the dispersion adjustment layer are the rate of change according to the position. The sign may be reversed. In other words, the phase delay profile represented by the phase delay layer and the phase delay profile represented by the dispersion adjustment layer may have opposite signs of change rates with respect to positions.

The phase delay layer and the dispersion adjustment layer may have different ratios of the dispersion change rate (∂/∂r) (∂n/∂λ) according to the position to the effective refractive index change (∂n/∂r) according to the position.

In the case of the phase delay layer, as shown in the graph of FIG. 3 , the change width of the effective refractive index according to the position is larger than the change width of the effective refractive index according to the position of the dispersion control layer, as shown in FIG. 4 . Conversely, the dispersion, ie, the degree to which an effective refractive index differs according to wavelength, is smaller in the phase delay layer than in the dispersion control layer. Accordingly, the ratio of the dispersion change rate to the effective refractive index change according to the position has a larger value in the case of the dispersion control layer than in the case of the phase delay layer. To this end, the material included in the dispersion control layer may have greater dispersion than the material included in the phase delay layer. As a material having a large dispersion, for example, Si or TiO ₂ may be used, and as a material having a small dispersion, for example, SiO ₂ or Si ₃ N ₄ may be used. However, this is only exemplary and is not limited thereto. The ratio of the dispersion change rate to the effective refractive index change according to the position has a close relationship with the dispersion of the medium, the refractive index, the shape distribution, and the like. For example, when the refractive index of the material constituting the nanostructure is smaller than the refractive index of the surrounding material, the dispersion change rate according to the location is smaller than when the refractive index of the material of the nanostructure is larger than the refractive index of the surrounding material. Therefore, it is possible to adjust the ratio of the dispersion change rate to the effective refractive index change according to the location by combining different materials and shapes from the above example.

The specific details of the graphs of FIGS. 3 and 4 are an example in which the effective refractive index change tendency according to the position and the dispersion change rate to the effective refractive index change are different in the two layers, but the present invention is not limited thereto. In addition, although it is shown that the above-mentioned constant tendency appears in all positions of each region (R ₁ , R ₂ , ,,R _{k ), this means an overall tendency appearing in most regions.} For example, the effective refractive index change tendency of the first layer and the second layer may be the same at some positions. Some of these positions may occur because a predetermined height or width is not implemented at a predetermined position due to an error in the nanostructure process. Alternatively, a boundary region accompanied by a sharp change in the effective refractive index, that is, an effective refractive index change tendency different from the intended tendency in the boundary region adjacent to the _{regions (R 1} , R ₂ , ,,R _{k ) of the 2π zone may appear.} . In an embodiment, the region in which the effective refractive index change tendency of the two layers is opposite may be at least 50% or more, or 80% or more of the entire region. Here, the ratio is based on a length in a predetermined first direction (eg, a radial direction) indicating an effective refractive index change. That is, it means a ratio of the length in the first direction in which the effective refractive index change tendency of the two layers is opposite to the total length in the first direction in which the effective refractive index change is indicated.

5 is a graph exemplarily showing a phase delay profile for each wavelength by the meta-optical device of FIG. 1 .

The meta-optical device 100 in which two layers exhibiting the same properties as in the graphs of FIGS. 3 and 4 are combined may exhibit a phase delay profile without discontinuities according to positions.

Meanwhile, in the graph of FIG. 5 , the phase delay profiles for the three wavelengths are shifted by a constant value and have the same shape, which corresponds to a case where the dispersion is zero. However, this is only an example, and a phase delay profile having a variance greater than zero or smaller than zero may be implemented according to a detailed distribution distribution in the phase delay layer and the variance adjustment layer.

Hereinafter, a theory from which the above-described structure is derived in order to implement a phase delay profile having less phase discontinuity according to a position regardless of a wavelength will be examined.

In order to implement a phase delay profile with less discontinuity for light of a predetermined wavelength band, unit components having different phase delay magnitudes and different amounts of dispersion may be used in the meta-optical device 100 .

The phase delay of light passing through the unit components of the meta-optical device 100 can be expressed by linear approximation as follows.

식 (1)

Formula (1)

는 기준 위상 프로파일이다. where ω is 2π/λ, ω ₀ is 2π/λ ₀ , λ is the wavelength, λ ₀ is the center wavelength of the center of the predetermined wavelength band, A is the magnitude of the phase delay dispersion (∂φ/∂λ), and B is the center magnitude of the phase delay in wavelength (φ|λ=λ ₀ ),

is the reference phase profile.

In order to make the phase delay profile continuous according to the position of the meta optical element 100, a set of unit components having A and B values in the following ranges is required. The unit component refers to an optical structure having a shape dimension smaller than the sub-wavelength, ie, the central wavelength.

식 (2)

Equation (2)

식 (3)

Equation (3)

The required range of A varies depending on the chromatic aberration of the meta-optical element 10 , and when the meta-optical element 100 is a lens, the larger the lens diameter and the numerical aperture (Numerical Aperture), the wider it is. When the phase delay profiles according to positions in the operating wavelength range are the same, A=0. The required range of B, B1-B0, must be greater than 2π.

Assuming that the unit component of the meta-optical device 100 is a uniform medium capable of expressing an effective refractive index, the phase delay of light passing through the unit component can be expressed as follows.

식(4)

Equation (4)

where n is the effective refractive index and h is the height of the unit component.

Substituting Equation (4) into Equation (1), and setting the reference phase profile as follows to increase linearly with frequency to simplify the expression,

Effective refractive indices of unit components necessary for realizing a phase delay profile with less discontinuity can be expressed as follows.

식(5)

Equation (5)

or

식(6)

Equation (6)

As can be seen from Equations (5) and (6), it can be seen that effective refractive indices having various sizes and dispersions must be implemented through unit components in order to implement a phase delay profile with less discontinuity.

For example, under the condition of A = 0, which is the simplest case, unit components in which the change in effective refractive index dispersion has a positive value as the phase delay at the center wavelength increases is required, and this condition is expressed as an equation at the center wavelength. It is shown as follows.

식(7a)

Equation (7a)

식(7b)

Equation (7b)

where n is the effective refractive index at the central wavelength (λ _{0 ).} .

That is, as the effective refractive index at the center wavelength increases, the change in the size of the dispersion of the effective refractive index should have a positive value.

However, in most of the optical materials existing in nature, dispersion has a negative value at an optical frequency, and the size of dispersion tends to increase as the refractive index increases. It is difficult to satisfy Equations 7(a) and 7(b) only by the method.

That is, since the effective refractive index of the non-resonant unit element generally has the following characteristics, it is difficult to satisfy Equations 7a and 7b. .

식(8)

Equation (8)

For example, in the case of changing the phase retardation at the central wavelength with the width of the nanopillar, which is a commonly used method, increasing the width of the nanopillar increases the effective refractive index, but due to the electric field focusing of the waveguide mode, the refractive index dispersion is negative. The size also increases, that is, a variance change opposite to Equations 7a and 7b is obtained.

In the above description, the case of the simplest condition of A=0 condition is exemplified, and when A is not 0, unit components having more various combinations of refractive index dispersion and refractive index size are required, so the existing technology has a wide wavelength It is difficult to implement a high-efficiency meta-optical device in the range.

The meta-optical device 100 according to the embodiment is proposed to have a structure in which dispersion can be precisely controlled by using a unit component that is divided into a plurality of layers having different properties according to the position and wavelength of the effective refractive index.

Similar to Equation (6), the relational expression between the effective refractive index of the unit component divided into a plurality of layers and the condition for a continuous phase profile can be expressed as follows.

식(9)

Equation (9)

where n _i is the effective refractive index of the ith layer, and h _i is the height of the unit component of the ith layer.

Similar to Equations (7a) and (7b), the condition for having a phase delay profile without discontinuity when A=0, which is the simplest condition, is expressed at the center wavelength as follows.

식(10a)

Equation (10a)

식(10b)

Equation (10b)

Assuming that the effective refractive index of each layer constituting the meta optical element 100 satisfies Equation (8), in order to satisfy Equations (10a) and (10b), at least one layer has the magnitude of the phase delay at the center wavelength as shown below. The effective refractive index change according to the change in (B) should be negative.

식(11)

Equation (11)

where n _j is the effective refractive index at the center wavelength of the j layer. In general, when the refractive index is high, the change to B of the effective refractive index dispersion of the j-layer has a positive value when considering the properties of the material in the natural world, where dispersion is increased.

Since the change with respect to B of the variance of the j layer has a positive value rather than a negative value, it becomes possible to satisfy Equations 10a and 10b according to certain conditions.

For example, when the meta-optical device 100 includes two layers, the heights h1 and h2 of each layer are as follows.

식 12(a)

Equation 12(a)

식 12(b)

Equation 12(b)

Here, in order for the heights h1 and h2 to have positive values, the following conditions must be satisfied.

식 (13a)

Equation (13a)

식 (13b)

Equation (13b)

식 (13c)

formula (13c)

Assuming that each layer satisfies Equation (8), Equations 13b and 13c can be written as follows.

식 (14)

Equation (14)

_{That is, the refractive index change rate (∂n i} /∂B) of the i-th layer according to the change in the magnitude (B) of the phase delay at the required center wavelength is positive, and the refractive index change rate (∂n) of the j-th layer according to the change in B _j /∂B) is negative, (Equation 14), the rate of change of dispersion ((∂/∂B(∂n _j /∂λ)) compared to the rate of change of refractive index for B of the j-th layer (∂n _{j /∂B)} If the size is larger than that of the i-th layer (Equation 13a), Equation 7 is satisfied to realize a phase delay profile with less discontinuity in the operating wavelength region.

The above conditions may be satisfied by using a material having a different refractive index and dispersion for the unit components constituting each layer and using a different design parameter space for each layer.

In the above description, n, φ, A, B, etc. are described as a function of a wavelength by fixing a position based on a unit component, but these are all concepts expressed as a function of a position. Therefore, in each layer of the meta-optical device 100, the effective refractive index change according to the position (∂n/∂r) and the dispersion change according to the position (∂/∂r(∂n/∂λ) are adjusted to adjust the above conditions can be satisfied

6 is a cross-sectional view showing a schematic structure of a meta-optical device according to an embodiment, and FIGS. 7A and 7B are perspective views illustrating an exemplary shape of a nanostructure that can be employed in the meta-optical device of FIG. 6 .

The meta-optical device 101 includes a first layer 121 and a second layer 161 , and further includes a substrate SU for supporting the first layer 121 and the second layer 161 . can do.

The first layer 121 includes a plurality of first nanostructures NS1 and a first peripheral material EN11 surrounding the plurality of first nanostructures NS1 . The first nanostructure NS1 may have a width d1 and a height h1 determined according to a location. As illustrated, the height h1 of the first nanostructure NS1 may be the same, but is not limited thereto.

The second layer 161 includes a plurality of second nanostructures NS2 and a second peripheral material EN21 surrounding the plurality of second nanostructures NS2 . The second nanostructure NS2 may have a width d2 and a height h2 determined according to a location. As illustrated, the height h2 of the second nanostructure NS2 may be the same, but is not limited thereto.

The substrate SU has a transparent property to light in the operating wavelength band of the meta optical element 101, and is made of glass (fused silica, BK7, etc.), quartz, polymer (PMMA, SU-8, etc.) and other transparent plastics. It may be made of any one of the materials.

The first nanostructure NS1 and the second nanostructure NS2 may have an aspect ratio greater than 1 to avoid optical resonance inside the structure. That is, h1/d1 and h2/d2 may be greater than 1, for example, greater than 2.

The first nanostructure NS1 and the second nanostructure NS2 at positions facing each other may reach the repeating unit element UE. The detailed shape included in the unit element UE, that is, the width d1, the height h1 of the first nanostructure NS1, the width d2 of the second nanostructure NS2, the height h2, The arrangement period p of the unit element UE is set appropriately for the phase delay value required at each position.

d1, d2, and p may be dimensions of sub-wavelengths. That is, d1, d2, and p may be smaller than _{the central wavelength (λ 0} ) of the operating wavelength band of the meta optical element 101 . h1 and h2 may be greater than _{λ 0 .} h1 and h2 may be greater than _{λ 0 and less than 10λ 0 .}

A spacer layer 140 may be interposed between the first layer 121 and the second layer 161 . The spacer layer 140 may have a lower refractive index than that of the first nanostructure NS1 and the second nanostructure NS2 . The spacer layer 140 may be made of the same material as the first peripheral material EN11 , or may be made of the same material as the second peripheral material EN21 . The thickness s of the spacer layer 140 may be 400 nm or less. The spacer layer 140 may be omitted. In other words, the thickness s of the spacer layer 140 may be zero.

The first nanostructure NS1 and the second nanostructure NS2 may be a columnar structure. For example, it may have a square prism shape as shown in FIG. 7A or a cylindrical shape as shown in FIG. 7B . The indicated width, D, corresponds to d1 or d2, and the height H corresponds to h1 or h2. In addition, various columnar shapes having a cross-sectional shape of a rectangle, a cross, a polygon, or an ellipse may be applied to the first nanostructure NS1 and the second nanostructure NS2 .

In the present embodiment, the first nanostructure NS1 may have a higher refractive index than the first surrounding material EN11 , and the second nanostructure NS2 may have a higher refractive index than the second surrounding material EN21 . According to the arrangement of the refractive index, the first nanostructures NS1 and the second nanostructures NS2 have a tendency to change the widths d1 and d2 in one direction away from the center of the meta-optical device 101 . can be set. Accordingly, in the first layer 121 and the second layer 161 , the sign of the effective refractive index change according to the position is opposite to each other. In addition, the first layer 121 and the second layer 161 may have different ratios of dispersion change to effective refractive index change, so that the material, shape, dimension, etc. included in the unit element UE may be set according to the location. have.

Any one of the first layer 121 and the second layer 1610 shows a phase profile of the same tendency as the target phase profile to be implemented by the meta-optical device 101, that is, of the same tendency as the target phase profile, It may be a phase retardation layer having an effective refractive index change according to a position, and the other layer may be a dispersion adjustment layer showing an effective refractive index change in a tendency opposite to the target phase profile.

For the layer that is the dispersion control layer, the change tendency of the material and width may be set so that the ratio of the dispersion change rate to the effective refractive index change is larger than that of the other layers.

This embodiment may be modified to a case in which the refractive index of the first nanostructure NS1 is smaller than that of the first surrounding material EN11 and the second nanostructure NS2 has a smaller refractive index than that of the second surrounding material EN21 .

Hereinafter, a meta-optical device according to various embodiments will be described. In the description of the embodiments below, differences from the meta optical element 101 of FIG. 6 will be mainly described, and the above description may be applied to components not described.

8 is a cross-sectional view showing a schematic structure of a meta-optical device according to another embodiment.

The meta-optical device 102 includes a first layer 122 , a second layer 162 , and a substrate SU supporting the first layer 122 and the second layer 162 . The first layer 122 includes a plurality of first nanostructures NS1 and a first peripheral material EN12 surrounding the first nanostructures NS1 . The second layer 162 includes a plurality of second nanostructures NS2 and a second peripheral material EN22 surrounding the plurality of second nanostructures NS2 .

In this embodiment, unlike the meta-optical device 101 of FIG. 6 , the first nanostructure NS1 may have a lower refractive index than the first peripheral material EN12 . The second nanostructure NS2 may have a higher refractive index than that of the second surrounding material EN22 .

In this refractive index arrangement, the widths d1 and d2 of the first nanostructures NS1 and the second nanostructures NS2 in one direction away from the center of the meta optical element 102 tend to change. These are set equal to each other. Accordingly, in the first layer 122 and the second layer 162 , the sign of the effective refractive index change according to the position is opposite to each other. In addition, the materials included in each layer and the degree of a tendency to change in width may be set for the first layer 122 and the second layer 162 to have different ratios of dispersion change to effective refractive index change.

In this embodiment, the first nanostructure NS1 may have a higher refractive index than that of the first surrounding material EN12 , and the second nanostructure NS2 may be modified to have a lower refractive index than that of the second surrounding material EN22 . .

9 is a cross-sectional view showing a schematic structure of a meta-optical device according to another embodiment. 10A and 10B are plan views illustrating exemplary shapes of a first nanostructure that may be employed in the first layer of the meta-optical device of FIG. 9 .

The meta-optical device 103 includes a first layer 123 , a second layer 163 , and a substrate SU supporting the first layer 123 and the second layer 163 .

The first layer 123 includes a plurality of first nanostructures NS1 and a first peripheral material EN13 surrounding the plurality of first nanostructures NS1 . The second layer 163 includes a plurality of second nanostructures NS2 and a second peripheral material EN23 surrounding the plurality of second nanostructures NS2 .

The first nanostructure NS1 may have a shape including an inner pillar 10 having a width of dc1 and a shell pillar 20 surrounding the inner pillar 10 . The refractive index of the inner pillar 10 may be lower than that of the shell pillar 20 , and the refractive index of the shell pillar 20 may be higher than that of the first peripheral material EN13 .

The second nanostructure NS2 may have a higher refractive index than that of the second surrounding material EN23 .

In this refractive index arrangement, the tendency of the width of the first nanostructures NS1 and the second nanostructures NS2 to change in one direction away from the center of the meta optical element 103 may be set to be opposite to each other. have. Accordingly, in the first layer 123 and the second layer 163, the signs of the effective refractive index change according to positions are opposite to each other. In addition, the details of the unit element UE may be set so that the ratio of the variance change rate to the effective refractive index change is different for the first layer 123 and the second layer 163 .

Any one of the first layer 123 and the second layer 163 may be a phase delay layer showing a phase profile of the same tendency as the target phase profile to be implemented by the meta-optical device 103, and the other layer is It may be a dispersion control layer.

On the other hand, when the first nanostructure NS1 provided in the first layer 123 is in a form in which the high refractive index shell pillar 20 is filled with the low refractive index inner pillar 10 , the first nanostructure NS1 As the width d1 of ) increases, a phenomenon in which the effective refractive index rapidly increases can be alleviated, and it is advantageous to minimize dispersion changes according to positions. In this regard, it is advantageous for the first layer 123 to be used as a phase delay layer showing a phase profile of the same tendency as the target phase profile to be implemented by the meta-optical device 103 . The second layer 163 is a dispersion control layer, and the change tendency of the material and width may be set in detail so that the ratio of the dispersion change rate to the effective refractive index change rate is greater than that of the first layer 123 .

11 is a graph showing the relationship between the detailed dimensions of the unit components of the meta-optical device of FIG. 9 and the phase delay.

The graph is for a case in which the first nanostructure NS1 has a shape as shown in FIG. 10A and the second nanostructure NS2 has a shape as shown in FIG. 7A . In the graph, the height of the first nanostructure NS1 and the heights h1 and h2 of the second nanostructure NS2 are fixed to constant values. The width d1 of the first nanostructure NS1, the width d2 of the second nanostructure NS2, the width dc1 of the inner pillar 10 included in the second nanostructure NS2, and the unit component By changing the arrangement period (p) of the UE, the phase delay of the light passing through these unit elements (UE) is shown.

From this graph, a detailed dimension of a unit element (UE) suitable for a required phase delay value may be set. In addition, such a graph can be obtained for different values of h1 and h2, and detailed dimensions of unit elements (UE) for each location can be set from these graphs, which are suitable for the target phase profile to be implemented.

12 and 13 are graphs showing the diffraction efficiency of the meta-optical device of FIG. 9 .

12 and 13 show diffraction efficiencies in a wavelength band of 400 nm to 700 nm with incident angles of 0°, 30°, and 60° for light in TE mode and TM mode, respectively.

The diffraction efficiency represents an energy ratio of the light diffracted in the intended diffraction direction among the light transmitted through the meta optical element 103 . As shown in the graph, the diffraction efficiency in the desired wavelength band is 0.8 or more, and shows a high value of almost 0.9 or more. This high diffraction efficiency can be attributed to the meta optical element 103 being designed to implement a target phase delay profile having almost no phase discontinuity in the wavelength band.

14 is a cross-sectional view showing a schematic structure of a meta-optical device according to another embodiment.

The first layer 124 of the meta-optical device 104 includes a plurality of first nanostructures NS1 and a first peripheral material EN14 surrounding the first nanostructures NS1 . The second layer 164 of the meta-optical device 104 includes a plurality of second nanostructures NS2 and a second peripheral material EN24 surrounding the plurality of second nanostructures NS2 .

The first nanostructure NS1 may have a shape including an inner pillar 10 having a width of dc1 and a shell pillar 20 surrounding the inner pillar 10 . The refractive index of the inner pillar 10 may be lower than that of the shell pillar 20 , and the refractive index of the shell pillar 20 may be higher than that of the first peripheral material EN14 .

Unlike the meta-optical element 103 of FIG. 9 , the meta-optical element 104 of the present embodiment may have a lower refractive index than the second nanostructure NS2 of the second peripheral material EN24 .

In this refractive index arrangement, the first nanostructures NS1 and the second nanostructures NS2 have the same tendency to change the width in one direction along one direction away from the center of the meta optical element 103 . have. Accordingly, in the first layer 124 and the second layer 164 , the sign of the effective refractive index change according to the position is opposite to each other. In addition, the materials included in the first layer 124 and the second layer 164 may have different ratios of the dispersion change to the effective refractive index change, and the degree of the tendency to change the width and the like may be set.

The first layer 124 may be a phase delay layer that exhibits a phase profile of the same tendency as the target phase profile to be implemented by the meta-optical device 104, and the second layer 164 is a dispersion control layer. 124), the details of the unit element UE may be set for each location so that the ratio of the variance change rate to the effective refractive index change is large.

15 is a cross-sectional view showing a schematic structure of a meta-optical device according to another embodiment.

The first layer 125 of the meta-optical device 105 includes a plurality of first nanostructures NS1 and a first peripheral material EN15 surrounding the first nanostructures NS1 . The second layer 165 of the meta-optical device 105 includes a plurality of second nanostructures NS2 and a second peripheral material EN25 surrounding the plurality of second nanostructures NS2 .

The first nanostructure NS1 has a hole shape surrounded by a first peripheral material EN15 , and the inside of the hole is empty, ie, air. The refractive index of the first nanostructure NS1 is 1, and has a lower refractive index than that of the first surrounding material EN15.

The second nanostructure NS2 has a higher refractive index than that of the second surrounding material EN25 .

The holes of the first nanostructures NS1 and the second nanostructures NS2 are unit components ( UE) is set. Accordingly, in the first layer 125 and the second layer 165 , the sign of the effective refractive index change according to the position is opposite to each other. Also, the materials included in the first layer 125 and the second layer 165 may have different ratios of dispersion change to effective refractive index change, and a degree of a tendency to change in width and the like may be set.

The first layer 125 may be a phase delay layer indicating a phase profile of the same tendency as the target phase profile to be implemented by the meta-optical device 105 . The second layer 165 is a dispersion control layer, and, compared to the first layer 125 , the details of the unit elements UE may be set for each location so that the ratio of the dispersion change to the effective refractive index change is large.

16 is a graph showing the phase delay according to the detailed dimensions of the first nanostructure constituting the first layer of the meta-optical device of FIG. 15 .

The graph is for a case in which the hole of the first nanostructure NS1 has a square cross-section, and the second nanostructure NS2 has a shape as shown in FIG. 7A . In the graph, the height of the first nanostructure NS1 and the height of the second nanostructure NS2 are fixed, and the width d1 of the first nanostructure NS1 and the width d2 of the second nanostructure NS2 are fixed. ), the arrangement period (p) of the unit element (UE) is changed, and the phase delay is shown accordingly.

From this graph, a detailed dimension of a unit element (UE) suitable for a required phase delay value may be set. In addition, such a graph can be obtained for different values of h1 and h2, and detailed dimensions of unit elements (UE) for each location can be set from these graphs, which are suitable for the target phase profile to be implemented.

17 is a graph showing the diffraction efficiency of the meta-optical device of FIG. 15 .

The graph is for incident light with an incident angle of 0°. In the wavelength range of 400 nm to 700 nm, it shows a high value of 0.9 or more, and shows a diffraction efficiency close to 1 in most wavelength bands.

These results show that the first nanostructure NS1 has a low refractive index inner pillar 10 and a high refractive index shell pillar 20 surrounding the meta optical element 103 according to the embodiment of FIG. 9 . It is analyzed that the diffraction efficiency is higher than that of This can be seen as a result that desired dispersion control becomes easier by using the hollow hole structure.

18 is a cross-sectional view showing a schematic structure of a meta-optical device according to another embodiment.

The first layer 126 of the meta-optical device 106 includes a plurality of first nanostructures NS1 and a first peripheral material EN16 surrounding the first nanostructures NS1 . The second layer 166 of the meta-optical device 106 includes a plurality of second nanostructures NS2 and a second peripheral material EN26 surrounding the plurality of second nanostructures NS2 .

The first nanostructure NS1 has a hole shape surrounded by the first peripheral material EN16, and the inside of the hole is empty, ie, air. The refractive index of the first nanostructure NS1 is 1, and has a lower refractive index than that of the first surrounding material EN16.

Unlike the meta-optical element 105 of FIG. 15 , in the meta-optical element 106 of this embodiment, the second nanostructure NS2 has a lower refractive index than the second peripheral material EN26 .

The holes of the first nanostructures NS1 and the second nanostructures NS2 are unit components for each position so that the tendency of the width of the first nanostructure NS1 to change in one direction away from the center of the meta optical element 105 is opposite to each other. (UE) is set. Accordingly, in the first layer 126 and the second layer 166, the sign of the effective refractive index change according to the position is opposite to each other. In addition, the materials included in the first layer 126 and the second layer 166 may have different ratios of the dispersion change to the effective refractive index change, and the degree of the tendency to change the width and the like may be set.

The first layer 126 may be a phase delay layer indicating a phase profile of the same tendency as the target phase profile to be implemented by the meta-optical device 106 . The second layer 166 is a dispersion control layer, and compared to the first layer 126 , the details of the unit element UE for each location may be set so that the ratio of the dispersion change to the effective refractive index change is large.

In the description described above in the description of the meta optical element 103, 104, 105, 106 of FIGS. 9, 14, 15, 18, the first layer 123, 124, 125, 126 A layer (phase retardation layer) exhibiting an effective refractive index change (and phase retardation profile) with the same trend as this target phase retardation profile, the second layer 164 , 164 , 165 , 166 tends to be opposite to the target retardation profile Although it has been described that it can function as a layer (dispersion control layer) exhibiting an effective refractive index change (and phase retardation profile) of , it is not limited thereto. In other words, the described example describes that a nanostructure having a hole shape or a shape including an inner pillar and a shell pillar has an advantage to be applied as a phase retardation layer, and the structure is a dispersion control layer according to refractive index distribution. It is also possible to be applied as a nanostructure of

The above-described meta-optical elements may exhibit various optical functions, such as a lens, a beam deflector, and a beam shaper, and may exhibit various optical functions by combining with general optical elements. For example, when the meta-optical device in the case where the phase delay dispersion (A=∂φ/∂λ) is 0 is implemented as a lens, a predetermined chromatic aberration may be exhibited. This chromatic aberration is negative chromatic aberration in which the wavelength and focal length are inversely proportional to each other, and is opposite to the positive chromatic aberration in which a general refractive lens indicates a focal length proportional to wavelength. This property can also be expressed as a negative Abbe number. Therefore, the meta-optical element exhibits a predetermined refractive power in combination with general refractive lenses, and may serve to correct chromatic aberration of the refractive lenses.

Many of the above descriptions were derived on the assumption that the phase delay profile illustrated in FIG. 5 , that is, the phase delay dispersion according to wavelength (A=∂φ/∂λ) is zero. However, using the same principle, i.e., employing a layer having a refractive index change of the same tendency as the target phase retardation profile and a layer having a refractive index change of the opposite tendency, and positioning the ratio of the refractive index change to the effective refractive index change in each layer In a manner that adjusts according to It is also possible to implement a meta-optical device.

19 is a graph exemplarily showing a phase delay profile for each wavelength by an optical meta-optical device according to another embodiment. Here, R, G, and B may be a relatively long wavelength, a medium wavelength, or a short wavelength, respectively. For example, R may be 700 nm, G may be 550 nm, and B may be 400 nm.

The exemplified phase delay profile is a case where a region in which the phase delay dispersion with respect to wavelength (∂φ/∂λ) is less than zero, a region equal to zero, and a region greater than zero all exist. When r0 is the position where the phase delay dispersion (∂φ/∂λ) becomes 0 (the position where the slope of the reference phase profile and the phase delay dispersion are the same), the phase delay dispersion (∂φ) in the region where the position r is smaller than r0 /∂λ) is less than 0, and the phase delay dispersion (∂φ/∂λ) in the region where the position r is greater than r0 is greater than 0.

When the target phase delay profile is configured so that dispersion with respect to wavelength has such a shape, optical performance having chromatic aberration greater than that of general optical elements may be exhibited. This chromatic aberration is a negative chromatic aberration that indicates a focal length that is inversely proportional to the wavelength, and may be larger than that shown in a metal lens with zero phase delay dispersion (∂φ/∂λ) with respect to wavelength, and it is much more than that shown in general refractive lenses. can be large Since this property is a phase delay profile that makes chromatic aberration larger, it can be utilized for the function of separating incident light by wavelength. For example, when a beam deflector is implemented with the illustrated target phase delay profile, the incident light may be deflected in different directions depending on the wavelength. In addition, the exemplified target phase retardation profile can be utilized in a miniature spectrometer that splits incident light by wavelength. In addition, when the beam shaper is implemented with the exemplified target phase delay profile, a different beam distribution may be formed according to the wavelength of the incident light.

20 is a graph exemplarily showing a phase delay profile for each wavelength by an optical meta-optical device according to another embodiment. Here, R, G, and B may be a relatively long wavelength, a medium wavelength, or a short wavelength, respectively. For example, R can be 700 nm, G can be 550 nm, and B can be 400 nm.

The exemplified phase delay profile is a case where a region in which the phase delay dispersion with respect to wavelength (∂φ/∂λ) is less than zero, a region equal to zero, and a region greater than zero all exist. When r0 is the position where the phase delay dispersion (∂φ/∂λ) becomes 0 (the position where the slope of the reference phase profile and the phase delay dispersion become the same), the phase delay dispersion (∂φ) in the region where the position r is smaller than r0 /∂λ) is greater than 0, and the phase delay dispersion (∂φ/∂λ) in the region where the position r is greater than r0 is less than zero.

If the target phase retardation profile is configured such that dispersion with respect to the wavelength has such a shape, the meta-optical device may exhibit achromatic optical performance. For example, when such a meta-optical device is a lens, incident light is focused without deviation according to wavelength. For example, when such a meta-optical device is a beam deflector, incident light exhibits a constant deflection angle without deviation according to wavelength. For example, when the meta-optical device is a beam shaper, incident light has a beam distribution of a predetermined designed pattern without deviation according to wavelength.

The above-described meta-optical devices may exhibit various optical functions by setting a target phase profile according to optical performance in a desired wavelength band. In addition, since the phase discontinuity can be minimized, the optical efficiency exhibiting the above-described optical function can be increased. In addition, since the sign of the phase delay dispersion (∂φ/∂λ) according to the wavelength can be adjusted to 0, greater than 0 or less than 0, various types of performance can be implemented.

The above-described meta-optical devices may be applied to various electronic devices. For example, smartphones, wearable devices, Internet of Things (IoT) devices, home appliances, tablet PCs (Personal Computers), PDAs (Personal Digital Assistants), PMPs (portable multimedia players), navigation (navigation) , a drone, a robot, an unmanned vehicle, an autonomous vehicle, an advanced driver assistance system (ADAS), and the like.

21 is a block diagram illustrating a schematic configuration of an electronic device according to an embodiment.

Referring to FIG. 21 , in a network environment 2200 , an electronic device 2201 communicates with another electronic device 2202 through a first network 2298 (such as a short-range wireless communication network) or a second network 2299 . It may communicate with another electronic device 2204 and/or the server 2208 via (such as a long-distance wireless communication network). The electronic device 2201 may communicate with the electronic device 2204 through the server 2208 . The electronic device 2201 includes a processor 2220 , a memory 2230 , an input device 2250 , an audio output device 2255 , a display device 2260 , an audio module 2270 , a sensor module 2210 , and an interface 2277 . ), a haptic module 2279 , a camera module 2280 , a power management module 2288 , a battery 2289 , a communication module 2290 , a subscriber identification module 2296 , and/or an antenna module 2297 . can In the electronic device 2201 , some of these components (eg, the display device 2260 ) may be omitted or other components may be added. Some of these components may be implemented as one integrated circuit. For example, the fingerprint sensor 2211 of the sensor module 2210, an iris sensor, an illuminance sensor, etc. may be implemented by being embedded in the display device 2260 (display, etc.).

The processor 2220 may execute software (such as a program 2240) to control one or a plurality of other components (hardware, software components, etc.) of the electronic device 2201 connected to the processor 2220, and , various data processing or operations can be performed. As part of data processing or computation, processor 2220 loads commands and/or data received from other components (sensor module 2210, communication module 2290, etc.) into volatile memory 2232, and It may process commands and/or data stored in 2232 , and store the resulting data in non-volatile memory 2234 . The processor 2220 includes a main processor 2221 (central processing unit, application processor, etc.) and an auxiliary processor 2223 (graphic processing unit, image signal processor, sensor hub processor, communication processor, etc.) that can be operated independently or together with it. may include The auxiliary processor 2223 may use less power than the main processor 2221 and may perform a specialized function.

The secondary processor 2223 is configured to replace the main processor 2221 while the main processor 2221 is in an inactive state (sleep state) or to the main processor 2221 while the main processor 2221 is in an active state (application execution state). Together with the processor 2221 , functions and/or states related to some of the components of the electronic device 2201 (display device 2260 , sensor module 2210 , communication module 2290 , etc.) may be controlled. can The auxiliary processor 2223 (image signal processor, communication processor, etc.) may be implemented as a part of other functionally related components (camera module 2280, communication module 2290, etc.).

The memory 2230 may store various data required by components of the electronic device 2201 (the processor 2220 , the sensor module 2276 , etc.). Data may include, for example, input data and/or output data for software (such as program 2240) and instructions related thereto. The memory 2230 may include a volatile memory 2232 and/or a non-volatile memory 2234 .

The program 2240 may be stored as software in the memory 2230 , and may include an operating system 2242 , middleware 2244 , and/or applications 2246 .

The input device 2250 may receive a command and/or data to be used in a component (eg, the processor 2220 ) of the electronic device 2201 from an external (eg, a user) of the electronic device 2201 . The input device 2250 may include a microphone, a mouse, a keyboard, and/or a digital pen (such as a stylus pen).

The sound output device 2255 may output a sound signal to the outside of the electronic device 2201 . The sound output device 2255 may include a speaker and/or a receiver. The speaker can be used for general purposes such as multimedia playback or recording playback, and the receiver can be used to receive incoming calls. The receiver may be integrated as a part of the speaker or may be implemented as an independent device.

The display device 2260 may visually provide information to the outside of the electronic device 2201 . The display device 2260 may include a display, a hologram device, or a projector and a control circuit for controlling the corresponding device. The display device 2260 may include a touch circuitry configured to sense a touch, and/or a sensor circuitry configured to measure the intensity of force generated by the touch (such as a pressure sensor).

The audio module 2270 may convert a sound into an electric signal or, conversely, convert an electric signal into a sound. The audio module 2270 obtains a sound through the input device 2250 or other electronic device (such as the electronic device 2102 ) directly or wirelessly connected to the sound output device 2255 and/or the electronic device 2201 . ) can output sound through the speaker and/or headphones.

The sensor module 2210 detects an operating state (power, temperature, etc.) of the electronic device 2201 or an external environmental state (user state, etc.), and generates an electrical signal and/or data value corresponding to the sensed state. can do. The sensor module 2210 may include a fingerprint sensor 2211 , an acceleration sensor 2212 , a position sensor 2213 , a 3D sensor 2214 , and the like, in addition to an iris sensor, a gyro sensor, a barometric pressure sensor, and a magnetic sensor. , a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, and/or an illuminance sensor.

The 3D sensor 2214 irradiates a predetermined light to the object and analyzes the light reflected from the object to sense the shape, movement, etc. of the object, and the meta-optical elements 100 and 101 according to the above-described embodiments ( 102), 103, 104, 105, and 106 may be provided.

The interface 2277 may support one or more specified protocols that may be used by the electronic device 2201 to directly or wirelessly connect with another electronic device (such as the electronic device 2102 ). The interface 2277 may include a High Definition Multimedia Interface (HDMI), a Universal Serial Bus (USB) interface, an SD card interface, and/or an audio interface.

The connection terminal 2278 may include a connector through which the electronic device 2201 may be physically connected to another electronic device (eg, the electronic device 2102 ). The connection terminal 2278 may include an HDMI connector, a USB connector, an SD card connector, and/or an audio connector (such as a headphone connector).

The haptic module 2279 may convert an electrical signal into a mechanical stimulus (vibration, movement, etc.) or an electrical stimulus that the user can perceive through tactile or kinesthetic sense. The haptic module 2279 may include a motor, a piezoelectric element, and/or an electrical stimulation device.

The camera module 2280 may capture still images and moving images. The camera module 2280 may include a lens assembly including one or more lenses, image sensors, image signal processors, and/or flashes. The lens assembly included in the camera module 2280 may collect light emitted from a subject, which is an image taking object, and the lens assembly includes the meta optical elements 100, 101, 102, ( 103), any one of 104, 105, and 106 may be included.

The power management module 2288 may manage power supplied to the electronic device 2201 . The power management module 388 may be implemented as part of a Power Management Integrated Circuit (PMIC).

The battery 2289 may supply power to components of the electronic device 2201 . Battery 2289 may include a non-rechargeable primary cell, a rechargeable secondary cell, and/or a fuel cell.

Communication module 2290 establishes a direct (wired) communication channel and/or wireless communication channel between the electronic device 2201 and other electronic devices (electronic device 2102, electronic device 2104, server 2108, etc.); and performing communication through an established communication channel. The communication module 2290 may include one or more communication processors that operate independently of the processor 2220 (such as an application processor) and support direct communication and/or wireless communication. The communication module 2290 may include a wireless communication module 2292 (a cellular communication module, a short-range wireless communication module, a Global Navigation Satellite System (GNSS, etc.) communication module) and/or a wired communication module 2294 (Local Area Network (LAN) communication). module, power line communication module, etc.). Among these communication modules, a corresponding communication module is a first network 2298 (a short-range communication network such as Bluetooth, WiFi Direct, or Infrared Data Association (IrDA)) or a second network 2299 (a cellular network, the Internet, or a computer network (LAN) , WAN, etc.) through a telecommunication network) and may communicate with other electronic devices. These various types of communication modules may be integrated into one component (single chip, etc.) or implemented as a plurality of components (plural chips) separate from each other. The wireless communication module 2292 may use subscriber information (such as International Mobile Subscriber Identifier (IMSI)) stored in the subscriber identification module 2296 within a communication network, such as the first network 2298 and/or the second network 2299 . may identify and authenticate the electronic device 2201 .

The antenna module 2297 may transmit or receive signals and/or power to the outside (eg, other electronic devices). The antenna may include a radiator having a conductive pattern formed on a substrate (PCB, etc.). The antenna module 2297 may include one or a plurality of antennas. When a plurality of antennas are included, an antenna suitable for a communication method used in a communication network such as the first network 2298 and/or the second network 2299 is selected from among the plurality of antennas by the communication module 2290 . can Signals and/or power may be transmitted or received between the communication module 2290 and another electronic device through the selected antenna. In addition to the antenna, other components (such as an RFIC) may be included as a part of the antenna module 2297 .

Some of the components are connected to each other through communication methods between peripheral devices (bus, GPIO (General Purpose Input and Output), SPI (Serial Peripheral Interface), MIPI (Mobile Industry Processor Interface), etc.) and signals (commands, data, etc.) ) are interchangeable.

The command or data may be transmitted or received between the electronic device 2201 and the external electronic device 2204 through the server 2108 connected to the second network 2299 . The other electronic devices 2202 and 2204 may be the same or different types of electronic devices 2201 . All or some of the operations executed in the electronic device 2201 may be executed in one or more of the other electronic devices 2202 , 2204 , and 2208 . For example, when the electronic device 2201 needs to perform a function or service, it requests one or more other electronic devices to perform part or all of the function or service instead of executing the function or service itself. can One or more other electronic devices receiving the request may execute an additional function or service related to the request, and transmit a result of the execution to the electronic device 2201 . For this purpose, cloud computing, distributed computing, and/or client-server computing technologies may be used.

22 is a block diagram illustrating a schematic configuration of a camera module included in the electronic device of FIG. 21 .

Referring to FIG. 23 , the camera module 2280 includes a lens assembly 2310 , a flash 2320 , an image sensor 2330 , an image stabilizer 2340 , a memory 2350 (buffer memory, etc.), and/or an image signal. A processor 2360 may be included. The lens assembly 2310 may collect light emitted from a subject, which is an image to be photographed, and may be any one of the aforementioned meta optical elements 100, 101, 102, 103, 104, 105, and 106. may be included. The lens assembly 2310 may include one or more refractive lenses and a meta optical element. The meta-optical element provided therein may be designed as a lens having a target phase delay profile that exhibits dispersion suitable for a predetermined aberration correction and a predetermined refractive index. The lens assembly 2310 having such a meta-optical element may implement a desired optical performance and have a short optical length.

The camera module 2280 may further include an actuator. The actuator may drive a position of lens elements constituting the lens assembly 2310 and adjust a separation distance between the lens elements, for example, for zooming and/or autofocusing (AF).

The camera module 2280 may include a plurality of lens assemblies 2310 , and in this case, the camera module 2280 may be a dual camera, a 360 degree camera, or a spherical camera. Some of the plurality of lens assemblies 2310 may have the same lens property (angle of view, focal length, auto focus, F number, optical zoom, etc.), or may have different lens properties. The lens assembly 2310 may include a wide-angle lens or a telephoto lens.

The flash 2320 may emit light used to enhance light emitted or reflected from the subject. The flash 2320 may include one or more light emitting diodes (RGB (Red-Green-Blue) LED, White LED, Infrared LED, Ultraviolet LED, etc.), and/or a Xenon Lamp. The image sensor 2330 may be the image sensor 1200 described with reference to FIGS. 1, 5, and 7 , and converts light emitted or reflected from the subject and transmitted through the lens assembly 2310 into an electrical signal, so that the subject It is possible to obtain an image corresponding to . The image sensor 2330 may include one or a plurality of sensors selected from image sensors having different properties, such as an RGB sensor, a black and white (BW) sensor, an IR sensor, or a UV sensor. Each of the sensors included in the image sensor 2330 may be implemented as a CCD (Charged Coupled Device) sensor and/or a CMOS (Complementary Metal Oxide Semiconductor) sensor.

In response to the movement of the camera module 2280 or the electronic device 2301 including the same, the image stabilizer 2340 moves one or a plurality of lenses or image sensors 2330 included in the lens assembly 2310 in a specific direction. Alternatively, an operation characteristic of the image sensor 2330 may be controlled (adjustment of read-out timing, etc.) to compensate for a negative effect of movement. The image stabilizer 2340 detects the movement of the camera module 2280 or the electronic device 2301 using a gyro sensor (not shown) or an acceleration sensor (not shown) disposed inside or outside the camera module 2280. can The image stabilizer 2340 may be optically implemented.

The memory 2350 may store some or all data of an image acquired through the image sensor 2330 for a subsequent image processing operation. For example, when a plurality of images are acquired at high speed, the acquired original data (Bayer-Patterned data, high-resolution data, etc.) is stored in the memory 2350, only the low-resolution image is displayed, and then selected (user selection, etc.) It may be used to cause the original data of the image to be transmitted to the image signal processor 2360 . The memory 2350 may be integrated into the memory 2230 of the electronic device 2201 or may be configured as a separate memory operated independently.

The image signal processor 2360 may perform one or more image processing on an image acquired through the image sensor 2330 or image data stored in the memory 2350 . One or more image processing may be performed by generating a depth map, 3D modeling, creating a panorama, extracting feature points, synthesizing an image, and/or compensating an image (noise reduction, resolution adjustment, brightness adjustment, blurring), sharpening ( sharpening), softening (Softening, etc.) may be included. The image signal processor 2360 may perform control (exposure time control, readout timing control, etc.) on components (such as the image sensor 2330 ) included in the camera module 2280 . The image processed by the image signal processor 2360 is stored back in the memory 2350 for further processing or external components of the camera module 2280 (memory 2230, display device 2260, electronic device 2202) , the electronic device 2204 , the server 2208 , etc.). The image signal processor 2360 may be integrated into the processor 2220 or configured as a separate processor operated independently of the processor 2220 . When the image signal processor 2360 is composed of a processor 2220 and a separate processor, the image processed by the image signal processor 2360 is subjected to additional image processing by the processor 2220 and then displayed on the display device 2260 . can be displayed through

The electronic device 2201 may include a plurality of camera modules 2280 each having different properties or functions. In this case, one of the plurality of camera modules 2280 may be a wide-angle camera and the other may be a telephoto camera. Similarly, one of the plurality of camera modules 2280 may be a front camera and the other may be a rear camera.

23 is a block diagram illustrating a schematic configuration of a 3D sensor provided in the electronic device of FIG. 21 .

The 3D sensor 2214 senses the shape, movement, etc. of the object by irradiating a predetermined light to the object and receiving and analyzing the light reflected from the object. The 3D sensor 2214 includes a light source 2420 , a meta optical element 2410 , a light detection unit 2430 , a signal processing unit 2440 , and a memory 2450 . As the meta-optical element 2410, any one of the meta-optical elements 100, 101, 102, 103, 104, 105, and 106 according to the above-described embodiments may be employed, and a beam deflector or A target phase delay profile can be set to function as a beam shaper.

The light source 2420 irradiates light to be used to analyze the shape or position of the object. The light source 2420 may include a light source that generates and irradiates light having a small wavelength. The light source 2420 is LD (laser diode), LED (light emitting diode), SLD (super luminescent diode) that generates and irradiates light of a wavelength band suitable for analyzing the position and shape of an object, for example, light of an infrared band wavelength. It may include a light source, such as. The light source 2420 may be a tunable laser diode. The light source 2420 may generate and irradiate light of a plurality of different wavelength bands. The light source 2420 may generate and irradiate pulsed light or continuous light.

The meta optical element 2410 modulates the light irradiated from the light source 1100 and transmits the modulated light to the object. When the meta-optical element 2410 is a beam deflector, the meta-optical element 2410 may deflect incident light in a predetermined direction to direct it toward the object. When the meta-optical element 2410 is a beam shaper, the meta-optical element 2410 modulates the incident light so that the incident light has a distribution having a predetermined pattern. The meta optical element 2410 may form structured light suitable for 3D shape analysis.

As described above, the meta-optical element 2410 may set the phase delay dispersion (∂φ/∂λ) to 0 or a positive or negative number, and implement a continuous phase delay profile. Accordingly, it is possible to perform achromatic light modulation according to wavelength. Or, conversely, the deflection direction may be changed for each wavelength by enhancing the deviation according to the wavelength, or a different beam pattern may be formed for each wavelength and irradiated to the object.

The photodetector 2430 receives the reflected light of the light irradiated to the object via the meta-optical element 2410 . The photodetector 24430 may include an array of a plurality of sensors that sense light, or may consist of only one sensor.

The signal processing unit 2440 may analyze the shape of the object by processing the signal sensed by the photodetector 2430 . The signal processing unit 2440 may analyze a 3D shape including the depth position of the object.

For the 3D shape analysis, an operation for measuring the optical time of flight may be performed. Various arithmetic methods can be used to measure the optical flight time. For example, in the direct time measurement method, a distance is obtained by projecting pulsed light onto an object and measuring a time for the light to return after being reflected by the object with a timer. In the correlation method, a pulsed light is projected onto an object, and a distance is measured from the brightness of the reflected light reflected from the object. The phase delay measurement method is a method of projecting continuous wave light, such as a sine wave, onto an object, detecting the phase difference of the reflected light and converting it into a distance.

When the structured light is irradiated to the object, the depth position of the object may be calculated from a change in the pattern of the structured light reflected from the object, that is, a result of comparison with the incident structured light pattern. Depth information of the object may be extracted by tracking the pattern change for each coordinate of the structured light reflected from the object, and 3D information related to the shape and movement of the object may be extracted therefrom.

The memory 2450 may store programs and other data necessary for the operation of the signal processing unit 2440 .

The operation result of the signal processing unit 2440 , that is, information on the shape and location of the object may be transmitted to another unit in the electronic device 2200 or to another electronic device. For example, this information may be used by the application 2246 stored in the memory 2230 . Another electronic device to which the result is transmitted may be a display device or a printer that outputs the result. In addition, autonomous driving devices such as unmanned vehicles, autonomous vehicles, robots, drones, etc., smart phones, smart watches, mobile phones, personal digital assistants (PDAs), laptops, PCs, and various wearable devices (wearable) devices, other mobile or non-mobile computing devices, and Internet of Things devices.

Although the above-described meta-optical device and electronic device including the same have been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those of ordinary skill in the art may make various modifications and equivalent other embodiments therefrom. You will understand that it is possible. Therefore, the disclosed embodiments are to be considered in an illustrative rather than a restrictive sense. The scope of the present specification is indicated in the claims rather than the foregoing description, and all differences within an equivalent scope should be construed as included.

Claims (37)

It represents a predetermined target phase delay profile for incident light of a predetermined wavelength band,
a first layer including a plurality of first nanostructures and a first surrounding material surrounding them;
a second layer disposed on the first layer and including a plurality of second nanostructures and a second surrounding material surrounding them;
Wherein the first layer and the second layer include regions in which signs of effective refractive index change in a predetermined first direction are opposite to each other. According to claim 1,
The first layer and the second layer have different ratios of dispersion change to effective refractive index change in the first direction, a meta-optical device. According to claim 1,
The target phase delay profile has zero dispersion with respect to a wavelength of the predetermined wavelength band, a meta-optical device. According to claim 1,
The phase delay profile represented by the first layer and the target phase delay profile have the same sign of a change rate in the first direction, a meta optical element. 5. The method of claim 4,
The ratio of the dispersion change rate to the effective refractive index change in the first direction of the second layer is
Larger than the ratio of the dispersion change rate to the effective refractive index change in the first direction of the first layer, a meta-optical device. 6. The method of claim 5,
The material included in the second layer has a greater dispersion than the material included in the first layer, a meta-optical device. According to claim 1,
The phase delay profile represented by the first layer and the phase delay profile represented by the second layer have opposite signs of a change rate with respect to a position change in the first direction. According to claim 1,
wherein the target phase delay profile is a continuous function of position in the predetermined wavelength band. meta optical element. According to claim 1,
The first nanostructure and the second nanostructure is a columnar structure, a meta-optical device. 10. The method of claim 9,
The first nanostructure and the second nanostructure have a ratio of height to width greater than 2, a meta optical device. 10. The method of claim 9,
The height of the first nanostructure and the second nanostructure is greater than a central wavelength of the predetermined wavelength band, a meta-optical device. 10. The method of claim 9,
The first nanostructure has a higher refractive index than the first surrounding material,
The second nanostructure has a higher refractive index than the second surrounding material,
The first nanostructures and the second nanostructures are
A meta-optical element, wherein the tendency for width to change in one direction away from the center of the meta-optical element is opposite to each other. 10. The method of claim 9,
The first nanostructure has a lower refractive index than the first surrounding material,
The second nanostructure has a higher refractive index than the second surrounding material,
The first nanostructures and the second nanostructures are
A meta-optical element, wherein the tendency of the width of the one-direction to change along one direction away from the center of the meta-optical element is the same. 10. The method of claim 9,
The first nanostructure has a shape including an inner pillar and a shell pillar surrounding the inner pillar, a meta-optical device. , 15. The method of claim 14,
The refractive index of the inner pillar is lower than the refractive index of the shell pillar, meta-optical device. 16. The method of claim 15,
The refractive index of the shell pillar is higher than the refractive index of the first surrounding material, meta-optical device. 17. The method of claim 16,
The second nanostructure has a higher refractive index than the second surrounding material, a meta-optical device. 18. The method of claim 17,
The first nanostructures and the second nanostructures are
The tendency of the width of the one direction to change along one direction away from the center of the meta optical element is opposite to each other. 17. The method of claim 16,
The second nanostructure has a lower refractive index than the second surrounding material, a meta-optical device. 20. The method of claim 19,
The first nanostructures and the second nanostructures are
A meta-optical element, wherein the tendency to change the width of the one-direction along one direction away from the center of the meta-optical element is the same. 10. The method of claim 9,
The first nanostructure is a hole shape surrounded by the first surrounding material, a meta-optical device. 22. The method of claim 21,
The second nanostructure has a higher refractive index than the second surrounding material, a meta-optical device. 23. The method of claim 22,
The holes of the first nanostructures and the second nanostructures are
The tendency of the width of the one direction to change along one direction away from the center of the meta optical element is the same as each other, a meta optical element. 22. The method of claim 21,
The second nanostructure has a lower refractive index than the second surrounding material, a meta-optical device. 25. The method of claim 24,
The holes of the first nanostructures and the second nanostructures are
The tendency of the width of the one direction to change along one direction away from the center of the meta optical element is opposite to each other. According to claim 1,
A meta-optical device further comprising a support layer supporting the first layer and the second layer. According to claim 1,
A meta-optical device further comprising a spacer layer between the first layer and the second layer. According to claim 1,
The target phase delay profile has a dispersion with respect to a wavelength of the predetermined wavelength band is less than 0, a meta-optical device. According to claim 1,
The target phase delay profile has a dispersion with respect to a wavelength of the predetermined wavelength band is greater than 0, a meta-optical device. According to claim 1,
The meta-optical element is a lens, a meta-optical element. According to claim 1,
The meta-optical element is a beam deflector (beam deflector), meta-optical element. According to claim 1,
The meta-optical element is a beam shaper (beam shaper), meta-optical element. 33. The method of any one of claims 1 to 32,
The predetermined wavelength band is a wavelength range of 400 nm to 700 m, a meta-optical device. 33. The method of any one of claims 1 to 32,
The ratio of the length in the first direction of the region to the total length in the first direction of the meta-optical element is 80% or more. 33. The method of any one of claims 1 to 32,
A meta-optical device having a diffraction efficiency of 0.8 or more for light in the predetermined wavelength band. An imaging lens assembly comprising one or more refractive lenses and the meta-optical element of any one of claims 1 to 30;
and an image sensor that converts an optical image formed by the imaging lens into an electrical signal. light source;
33. A meta-optical device according to any one of claims 1 to 32, which modulates the light from the light source and transmits it to the object;
and a photodetector configured to sense light from the object.

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