A full-view plane three-dimensional display device based on metasurface

Abstract

The application discloses a full-view plane three-dimensional display device based on a metasurface. The application comprises a metasurface, a plane mirror and a support structure; the metasurface is composed of anisotropic subwavelength micro-nano structures, which can realize independent transmission and reflection amplitude and phase modulation of orthogonal polarization states; the plane mirror is composed of a metal film, and transparent material can be added on the plane mirror for protection; the support structure has no limitation on the manufacturing material, and is mainly responsible for fixing the mirror and designing the metasurface. The application projects three-dimensional information of an observed object to the outside of the device through the free modulation ability of the metasurface on different polarization states of light waves, fully plays the advantages of the metasurface, such as planarization, thinness and polarization controllability, provides a new implementation scheme for real-time three-dimensional observation of living bodies in biophotonics, and opens up a new train of thought for the application of the metasurface in biophotonics.

Description

Technical Field

[0001] This invention belongs to the fields of micro-nano optics, three-dimensional projection display, and biophotonics, and in particular relates to a full-field planar three-dimensional display device based on metasurfaces, which has great value in research on applications such as live biological display and observation of individual insect activities. Background Technology

[0002] Full-field-of-view live biological 3D imaging technology has always been a challenge in biophotonics and is crucial for studying the individual and group activities of organisms such as insects. Traditional studies of individual biological activities require placing real, live organisms in spaces separated by transparent partitions to observe the impact of biological vision on individual activities. For example, in studying the sex transformation of clownfish, transparent enclosures are used to observe whether the presence of a virtual female in the biological aquatic environment inhibits sex transformation in juvenile hermaphroditic clownfish. In this approach, the observable field of view is limited, and close-range observation between organisms is difficult. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a full-field planar 3D display device based on a metasurface. This solution utilizes a polarization-multiplexed planar metasurface to project a living organism from one space into another space with its entire field of view. The light field projected into the new space contains the object's 3D information, and this 3D image can be collided with, contacted, and intersected by real objects. This provides a new tool for research in fields such as biophotonics and has multi-disciplinary application value.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows:

[0005] A full-field planar three-dimensional display device based on a metasurface includes, from top to bottom, a metasurface with transmission and reflection light wave modulation function, a support structure, and a planar reflector.

[0006] The metasurface is composed of anisotropic micro- and nanostructures, which have different transmission and reflection responses to photons with different polarization states.

[0007] The anisotropic micro / nanostructure consists of a transparent substrate and subwavelength microstructures on the substrate. The transparent substrate is used to transmit incident light and support the subwavelength micro / nanostructure. The subwavelength micro / nanostructure is a nano-dielectric pillar, which can modulate the transmission and reflection coefficients for incident light waves.

[0008] The plane mirror is made of a thin metal film coated or bonded with a layer of transparent material. The plane mirror is used to reflect light and compress the imaging space.

[0009] The aforementioned support structure is used to fix the planar reflector and the metasurface, and to ensure that the relative distance is the designed distance.

[0010] The nano-dielectric pillars of the metasurface are anisotropic structures. x and y The dimensions of the directions are different and they have a certain rotation angle; the transmitted light and reflected light are modulated by phase and amplitude respectively, and for left and right rotating light, different modulation effects are achieved by rotating the structure and combining it with the Jones matrix.

[0011] The lattice constant of the nano-dielectric pillars of the metasurface is less than the working wavelength. For one polarization state, its transmittance is greater than 80% and there is no phase gradient modulation. For the orthogonal polarization state of the incident polarization state, the reflectance is greater than 80% and it is converted into the original incident polarization state. The reflection phase covers 0~2π.

[0012] The arrangement of the nano-dielectric pillars on the metasurface satisfies the following: for highly reflective polarization states, the phase distribution is optimized by ray optics simulation software, so that the light emitted by the observed object is reflected by the mirror to form a 3D real image above the metasurface.

[0013] The aforementioned metasurface-based full-field planar three-dimensional display device allows the incident light wave information to pass through completely without modulation for highly transmissive polarization states, thereby realizing the input of illumination light and the output of imaging light in the device.

[0014] The method for implementing the full-field planar three-dimensional display device based on metasurfaces includes the following steps:

[0015] Step (1) Determine the working wavelength, field of view, and focal length parameters of the metasurface based on the design specifications and process limitations;

[0016] The focal length of the metasurface for the polarization state of the reflected light must be less than the distance between the metasurface and the mirror. The focal length determines the magnification of the system.

[0017] Step (2) Based on the aperture and focal length obtained in step (1), optimize using formula (1) or ray optics simulation software to obtain the phase distribution of the metasurface:

[0018] (1)

[0019] In the formula, x , y For the spatial coordinates on the metasurface lens, f The focal length of the lens. λ The operating wavelength of the metasurface lens;

[0020] Step (3) Use electromagnetic simulation software to calculate the transmission and reflection amplitude and phase of nano-dielectric pillars of different sizes. When selecting the size of the nano-dielectric pillar, it is necessary to ensure that its lattice constant is less than the working wavelength, the reflection amplitude of the design polarization state at the working wavelength is close to 1, and convert it into an orthogonal polarization state. The reflection phase of nano-dielectric pillars of different sizes covers 0~2π, the transmission amplitude of its orthogonal polarization state is close to 1, and the phase is constant.

[0021] Step (4) Design the arrangement of nanodielectric pillars according to the phase requirements of each lattice position in the imaging part of the metasurface lens;

[0022] Step (5) Fabrication of a planar reflector: A thin metal film is deposited on a planar substrate, and a transparent material is coated or bonded to the reflector to provide protection;

[0023] Step (6) Prepare the support structure with a fixed spacing of the design spacing.

[0024] The beneficial effects of this invention are:

[0025] This invention projects the three-dimensional information of an object from a planar frame onto an outside-the-device field of view, allowing observation of different sides of the object from various angles outside the device. The projected image is a real image, which can be collided with, contacted, and intersected by real objects outside the device, making it possible to observe the impact of images on biological individuals in biophotonics. Compared to traditional 3D mirror display solutions, this invention has both upper and lower planar surfaces, facilitating the placement and movement of the observed object. Furthermore, it eliminates the need for openings for illumination and imaging beam transmission, allowing all light directly above the object to be collected, thus expanding the field of view. Attached Figure Description

[0026] Figure 1 This is a structural diagram of the anisotropic unit cell of the metasurface.

[0027] Figure 2 The transmissivity and reflectivity of the metasurface structure under different polarizations are given, where part (a) represents the reflectivity under different polarizations. x Transmittance of polarized light, (b) part is for different structural sizes y The reflection coefficient of polarized light.

[0028] Figure 3 This is a schematic diagram of the device's operation. It has a high reflection coefficient and phase modulation function for left-handed polarized light, and a high transmittance for right-handed polarized light.

[0029] Figure 4 The results are a set of simulated ray beams for the design device.

[0030] Figure 5 This is a schematic diagram of the imaging process using a traditional 3D mirror. Detailed Implementation

[0031] The invention will now be further described with reference to the accompanying drawings.

[0032] like Figure 1-5 As shown, a full-field planar three-dimensional display device based on a metasurface consists of a metasurface, a planar mirror, and a support device (the support device is not shown).

[0033] The metasurface is composed of anisotropic subwavelength micro / nanostructures, which exhibit different transmission and reflection responses to photons with different polarization states. The micro / nanostructures consist of a transparent substrate and subwavelength microstructures on one side of the substrate. These subwavelength micro / nanostructures can modulate the transmission and reflection coefficients for incident light waves and are composed of numerous nanometer-sized dielectric pillars. The transparent substrate serves to transmit the incident light field and support the subwavelength micro / nanostructures. The lattice period of each micro / nanostructure is... p Smaller than wavelength, it is in x and y Different dimensions in the direction, such as Figure 1 As shown, it can be rotated to have different responses to different orthogonal polarization states (such as left- or right-handed circular polarization and elliptical polarization).

[0034] The aforementioned planar reflector is composed of a thin metal film, such as a silver mirror or a gold mirror, and a layer of transparent material can be coated or bonded onto it for protection. This reflective layer achieves the reflection of light and the compression of the imaging space.

[0035] The supporting structure serves to fix the reflector and metasurface, ensuring that their relative distance is the designed distance.

[0036] Furthermore, the metasurface nanopillars are anisotropic structures, which in... x and y Different dimensions in the direction, such as Figure 1 As shown, it can have a certain rotation angle; the anisotropic structure can modulate the phase and amplitude of transmitted light and reflected light respectively, and for left and right rotating light, different modulation effects can also be achieved by rotating the structure and combining it with the Jones matrix.

[0037] Furthermore, the lattice constant of the metasurface nanopillars is smaller than the operating wavelength, and for a given polarization state, its transmittance is greater than 80%, but it lacks phase gradient modulation capability, such as... Figure 2 As shown in part (a), for its orthogonal polarization state, its reflectivity is greater than 80%, and it is converted into an orthogonal polarization state with a phase covering 0~2π, as shown in part (a). Figure 2 As shown in part (b).

[0038] Furthermore, for the arrangement of the metasurface dielectric pillars, the phase distribution of the highly reflective polarization state can be optimized using ray optics simulation software, ensuring that the light emitted from the observed object is reflected by the mirror and imaged above the metasurface, such as... Figure 3 As shown, this image is a 3D real image, and different perspectives of the object can be obtained by observing it from different angles.

[0039] Furthermore, for highly transmissive polarization states, metasurfaces can completely transmit incident light wave information without modulation, enabling them to function as both illumination light input and imaging light output in devices, such as... Figure 3 As shown.

[0040] A full-field planar 3D display method based on metasurfaces includes the following steps:

[0041] Step (1) Determine the working wavelength, field of view, focal length and other parameters of the metasurface according to the design requirements and process limitations.

[0042] The focal length of the metasurface for the polarization state of the reflected light must be smaller than the distance between the metasurface and the mirror, and its focal length determines the magnification of the system.

[0043] Step (2) Based on the aperture and focal length obtained in step (1), optimize using formula (1) or ray optics simulation software to obtain the phase distribution of the metasurface:

[0044] (1)

[0045] In the formula, x , y For the spatial coordinates on the metasurface lens, f The focal length of the lens. λ This is the operating wavelength of the metasurface lens. Figure 4 It is the result of ray tracing of a set of structures that transmits the real image of an object onto a metasurface.

[0046] Step (3) Use electromagnetic simulation software to calculate the transmission and reflection amplitudes and phases of nano-dielectric pillars of different sizes. When selecting the size of the nano-dielectric pillar, it is necessary to ensure that its lattice constant is less than the working wavelength, the reflection amplitude of the photon of the designed polarization state is >80% at the working wavelength, the transmission phase of the nano-dielectric pillars of different sizes covers 0~2π, the transmission amplitude of the orthogonal polarization state is >80%, and the phase is constant.

[0047] Step (4) Design the arrangement of nanodielectric pillars according to the phase requirements of each lattice position of the metasurface lens imaging part.

[0048] Step (5) Prepare a planar reflector: A metal reflector can be used. A thin metal film is deposited on a planar substrate. A transparent material can be applied or bonded to the reflector to provide protection.

[0049] Step (6) Prepare a support structure, which serves to fix the metasurface and the metal mirror. The fixed spacing is the designed spacing, and an opening or channel can be left for the object to be observed to be placed in.

[0050] Compared to traditional 3D mirror display solutions, such as Figure 5 As shown, the invention has flat surfaces on both the top and bottom, which facilitates the placement and movement of the observed object. Furthermore, it eliminates the need for openings for illumination and the transmission of imaging beams, allowing all light from directly above the object to be collected, thus expanding the field of view.

[0051] The embodiments described above can be further combined or replaced, and these embodiments are merely descriptions of preferred embodiments of the present invention, not limitations on the concept and scope of the present invention. Various changes and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the inventive concept are all within the protection scope of the present invention. The protection scope of the present invention is given by the appended claims and any equivalents.

Claims

1. A full-field planar three-dimensional display device based on metasurfaces, characterized in that, From top to bottom, it includes a metasurface with transmission and reflection modulation functions, a support structure, and a planar mirror; The metasurface is composed of anisotropic micro- and nanostructures, which have different transmission and reflection responses to photons with different polarization states. The anisotropic micro / nanostructure consists of a transparent substrate and subwavelength microstructures on the substrate. The transparent substrate is used to transmit incident light and support the subwavelength micro / nanostructure. The subwavelength micro / nanostructure is a nano-dielectric pillar, which can modulate the transmission and reflection coefficients for incident light waves. The plane mirror is made of a thin metal film coated or bonded with a layer of transparent material. The plane mirror is used to reflect light and compress the imaging space. The aforementioned support structure is used to fix the planar reflector and the metasurface, and to ensure that the relative distance is the designed distance.

2. The full-field planar three-dimensional display device based on metasurface according to claim 1, characterized in that, The nano-dielectric pillars of the metasurface are anisotropic structures. x and y The dimensions of the directions are different and they have a certain rotation angle; the transmitted light and reflected light are modulated by phase and amplitude respectively, and for left and right rotating light, different modulation effects are achieved by rotating the structure and combining it with the Jones matrix.

3. The full-field planar three-dimensional display device based on metasurface according to claim 2, characterized in that, The lattice constant of the nano-dielectric pillars of the metasurface is less than the working wavelength. For one polarization state, its transmittance is greater than 80% and there is no phase gradient modulation. For the orthogonal polarization state of the incident polarization state, the reflectance is greater than 80% and it is converted into the original incident polarization state. The reflection phase covers 0~2π.

4. The full-field planar three-dimensional display device based on metasurface according to claim 3, characterized in that, The arrangement of the nano-dielectric pillars on the metasurface satisfies the following: for highly reflective polarization states, the phase distribution is optimized by ray optics simulation software, so that the light emitted by the observed object is reflected by the mirror to form a 3D real image above the metasurface.

5. A full-field planar three-dimensional display device based on a metasurface according to claim 4, characterized in that, For highly transmissive polarization states, metasurfaces allow incident light wave information to pass through completely without modulation, thus enabling the input of illumination light and the output of imaging light in the device.

6. A display method for a full-field-of-view planar three-dimensional display device based on a metasurface according to any one of claims 1-5, characterized in that, Includes the following steps: Step (1) Determine the working wavelength, field of view, and focal length parameters of the metasurface based on the design specifications and process limitations; The focal length of the metasurface for the polarization state of the reflected light must be less than the distance between the metasurface and the mirror. The focal length determines the magnification of the system. Step (2) Based on the aperture and focal length obtained in step (1), optimize using formula (1) or ray optics simulation software to obtain the phase distribution of the metasurface: (1) In the formula, x , y For the spatial coordinates on the metasurface lens, f The focal length of the lens. λ The operating wavelength of the metasurface lens; Step (3) Use electromagnetic simulation software to calculate the transmission and reflection amplitude and phase of nano-dielectric pillars of different sizes. When selecting the size of the nano-dielectric pillar, it is necessary to ensure that its lattice constant is less than the working wavelength, the reflection amplitude of the design polarization state at the working wavelength is close to 1, and convert it into an orthogonal polarization state. The reflection phase of nano-dielectric pillars of different sizes covers 0~2π, the transmission amplitude of its orthogonal polarization state is close to 1, and the phase is constant. Step (4) Design the arrangement of nanodielectric pillars according to the phase requirements of each lattice position in the imaging part of the metasurface lens; Step (5) Fabrication of a planar reflector: A thin metal film is deposited on a planar substrate, and a transparent material is coated or bonded to the reflector to provide protection; Step (6) Prepare the support structure with a fixed spacing of the design spacing.

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