Microstructure-adjustable super-lens device and design method thereof

Abstract

The invention relates to a micro-structure adjustable super-lens device and a design method thereof, and belongs to the technical field of optical devices, the micro-structure adjustable super-lens device comprises a super-lens and an MEMS execution device, and the super-lens is suspended on the MEMS execution device; the super lens comprises a microstructure and a substrate, and the microstructure is arranged above the substrate. The characteristics of the super lens and dynamic control of the MEMS are combined, a self-adaptive optical system can be created, and the application field of the super lens is expanded.

Description

Technical Field

[0001] The present invention belongs to the field of optical devices, and in particular relates to a super lens device with adjustable microstructure and a design method thereof. Background Art

[0002] A superlens is an optical element that differs from a traditional lens. It is usually based on a special nanostructure or metamaterial, and its design can cause a light beam to produce unusual refraction, focusing and propagation behaviors through the superlens.

[0003] Compared to traditional lenses, metalenses can achieve more flexible modulation of light beams, such as achieving anomalous refraction, negative refraction, and other behaviors, thereby providing higher control performance for optical systems. Due to its special structural design, metalenses can be miniaturized and integrated, making them suitable for micro-optical systems that require highly precise control. The unique optical properties of metalenses provide new application prospects for photonics, nanotechnology, and new sensors, such as nano-imaging, photonic chips, mobile phones, intelligent robots, and automotive applications.

[0004] However, the arrangement of metalens microstructures has some limitations, including single functionality and wavelength restrictions. Metalens microstructures are typically designed for specific optical functions, which limits their versatility. Some metalens microstructures may be designed to be limited to specific wavelengths, making them difficult to apply to multiple wavelengths simultaneously, which restricts their use in multi-band optical applications. Summary of the Invention

[0005] The present application provides a metalens device with adjustable microstructure and a design method thereof to at least solve the above technical problems existing in the prior art.

[0006] On the one hand, an embodiment of the present application provides a superlens device with adjustable microstructure, including a superlens and a MEMS actuator, wherein the superlens is suspended on the MEMS actuator; the superlens includes a microstructure and a substrate, wherein the microstructure is arranged above the substrate.

[0007] In one possible implementation manner, the size of the MEMS actuator is the same as that of the substrate, the MEMS actuator is connected to the substrate, and the MEMS actuator is hollow in the middle.

[0008] In one embodiment, the microstructure has a scale of nanometer to micrometer, and an arrangement period is less than half of the incident wavelength.

[0009] In one embodiment, the phase distribution formula of the microstructure arrangement is as follows:

[0010]

[0011] Where λ is the wavelength, x and y are the coordinates of the metalens, and f is the focal length of the metalens.

[0012] In one embodiment, the metalens is transmissive and modulates the light beam using a propagation phase.

[0013] In one embodiment, the substrate is square in shape; and the microstructure is centrally symmetrical in shape.

[0014] In one embodiment, the microstructure is in the shape of a circle or a square.

[0015] In one embodiment, the MESMS actuator may be driven by electromagnetic, current or voltage.

[0016] Another aspect of the present invention provides a method for designing a superlens device, comprising the following steps:

[0017] S1. Determine application requirements and optical design

[0018] According to specific application requirements, optical design software is used to perform optical design and generate the phase distribution of specific metalens under different application requirements;

[0019] S2, FDTD simulation

[0020] S21. Select a suitable microstructure shape and substrate, and simulate the relationship between the geometric dimensions of the microstructure and the phase and transmittance;

[0021] S22, divide the microstructure phase 2π after the simulation into N equal parts, and find the microstructure closest to the corresponding phase. The phase division formula is as follows:

[0022]

[0023] Where Δφ is the phase interval, N is the type of microstructure, and the more types of N, the more continuous the phase;

[0024] S23. Screen out the microstructure size suitable for specific application requirements while ensuring that its transmittance and phase can cover all application wavelength requirements;

[0025] S3. Microstructure arrangement

[0026] According to application requirements, the screened microstructure units are arranged to obtain different arrangements;

[0027] S4. Fabrication of superlens

[0028] Choose one of the application requirement arrangements to make a metalens;

[0029] S5, Programming and MEMS Drive

[0030] Program and store the arrangement methods for different applications obtained by FDTD simulation.

[0031] In one embodiment, by triggering the adjustment of the MEMS-driven microstructure, a new microstructure arrangement can be generated to meet new application requirements.

[0032] Compared with the prior art, this application has the following advantages:

[0033] 1. This application combines the characteristics of metalens with the dynamic control of MEMS to create adaptive optical systems and expand the application areas of metalens;

[0034] 2. This application allows for the arrangement of microstructures on a metalens according to different application scenarios, thus meeting the requirements of various usage scenarios and multiple bands.

[0035] 3. This application can adaptively arrange the microstructure according to the external temperature, enabling use in high and low temperature environments, providing a new idea for athermal design. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure of the metalens device in the embodiment of the present application;

[0037] Figure 2 2 is a schematic diagram of an adjustment unit of a metalens device according to an embodiment of the present application;

[0038] Figure 3 Schematic diagram of the theoretical effect of the metalens in the embodiment of the present application;

[0039] Figure 4 is a flowchart of a method for designing a superlens device in an embodiment of the present application;

[0040] Description of reference numerals:

[0041] 1. Microstructure; 11. Microstructure unit; 2. Substrate; 21. Substrate unit; 3. MEMS actuator; 31. MEMS actuator unit. DETAILED DESCRIPTION

[0042] The present invention will be described in further detail below with reference to the accompanying drawings.

[0043] In the description of this application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0044] Microelectromechanical systems (MEMS) technology includes micro-actuators that can control the movement of lenses on a microscopic scale. Traditional MEMS galvanometers usually use MEMS manufacturing technology, combined with microelectronic components and mechanical structures, to achieve precise horizontal movement. This application combines the characteristics of superlens and the dynamic control of MEMS to create an adaptive optical system that can dynamically adjust the arrangement of micro-nanostructures on the superlens according to environmental changes or specific needs. On a superlens, the microstructure can be adjusted within a limited arrangement range according to different application scenarios, which can meet the needs of multiple usage scenarios and multiple bands.

[0045] refer to Figure 1 The present application discloses a metalens device with adjustable microstructure, comprising a metalens and a MEMS actuator 3, wherein the metalens is suspended on the MEMS actuator 3. The metalens is transmissive and modulates a light beam using a propagation phase.

[0046] The metalens comprises a microstructure 1 and a substrate 2, with the microstructure 1 positioned above the substrate 2. The substrate 2 is square in shape, and the microstructure can be designed to suit specific applications, including but not limited to centrally symmetrical shapes such as circular and square. The materials used for the substrate and microstructure are chosen to provide good transmittance and broad spectral coverage for incident light. The microstructure 1 is scaled on the nanometer-micrometer scale, with an arrangement period less than half the incident wavelength.

[0047] The MEMS actuator 3 is the same size as the substrate 2 and is connected to the substrate 2. The MEMS actuator 3 is hollowed out in the middle. The MEMS actuator 3 does not block the effective photosensitive area of the metalens and does not affect the optical performance of the microstructure 1.

[0048] refer to Figure 2 The super lens device is composed of several adjustment units, and any adjustment unit is composed of a microstructure unit 11, a substrate unit 21 and a MEMS actuator unit 31.

[0049] The unit consisting of the microstructure unit 11 and the substrate unit 21 is suspended on the MEMS actuator unit 31. The MEMS actuator unit 31 does not block the effective photosensitive area of the metalens and does not affect its optical performance. The MEMS actuator unit uses electromagnetic drive, current drive, or voltage drive to enable the unit consisting of the microstructure unit 11 and the substrate unit 21 to be horizontally displaced to achieve different microstructure arrangements. The MEMS system can achieve adjustable microstructure arrangements through preset programs.

[0050] The arrangement of the microstructure 1 satisfies the phase distribution in different scenarios, and the phase distribution formula is as follows:

[0051]

[0052] Where λ is the wavelength, x and y are the coordinates of the metalens, and f is the focal length of the metalens.

[0053] When combining a metalens with a MEMS system, the precision drive of the MEMS system can be used to achieve specific application requirements. The design method for any of the above metalens devices is as follows:

[0054] S1. Determine application requirements and optical design

[0055] According to specific application requirements, optical design software is used to perform optical design and generate the phase distribution of specific metalens under different application requirements;

[0056] S2, FDTD simulation

[0057] S21. Select a suitable microstructure and substrate, and simulate the relationship between the geometric dimensions of the microstructure and the phase and transmittance.

[0058] S22, divide the microstructure phase 2π after the simulation into N equal parts, and find the microstructure closest to the corresponding phase. The phase division formula is as follows:

[0059]

[0060] Where Δφ is the phase interval, N is the type of microstructure, and the more types of N, the more continuous the phase;

[0061] S23. Screen out the microstructure size suitable for specific application requirements while ensuring that its transmittance and phase can cover all application wavelength requirements;

[0062] S3. Microstructure arrangement

[0063] According to application requirements, the screened microstructure units are arranged to obtain different arrangements;

[0064] S4. Fabrication of superlens

[0065] Choose one of the application requirement arrangements to make a metalens;

[0066] S5, Programming and MEMS Drive

[0067] Program and store the configurations for different applications derived from FDTD simulations. By triggering the adjustment of the MEMS-driven microstructure, new microstructure configurations can be generated to meet new application requirements.

[0068] Taking the design of the receiving end lens that realizes 808nm and 940nm TOF at the same time as an example, according to the above process, Zemax is used to obtain the phase distribution φ of the metalens at 808nm and 940nm respectively. 808 、φ 940 The focal length and back focus parameters of the two are the same, but the binary surface phase distribution is different. The binary surface phase coefficient is shown in Table 1:

[0069] Table 1

[0070] wavelength Normalized radius <![CDATA[R1]]> <![CDATA[R2]]> <![CDATA[R3]]> <![CDATA[R4]]> <![CDATA[R5]]> 808nm 1 -2.68E3 1.97E3 -5.03E3 7.21E3 -3.92E3 940nm 1 -1.59E3 1.15 -4.35E-1 -1.07E-1 5.94E-2

[0071] In the FDTD simulation software, the light source wavelength was set to 808nm and 940nm respectively to simulate the transmission and phase of the nanorods. The simulation parameter settings are shown in Table 2:

[0072] Table 2

[0073] wavelength base Material diameter high cycle 808nm <![CDATA[Sio2]]> Si 100-200nm 835nm 500nm 940nm <![CDATA[Sio2]]> Si 100-200nm 835nm 500nm

[0074] Screening of the nanopillars revealed that under eight nanopillar diameters, the phases of 808nm and 940nm can cover 0-2π, and the transmittance is >80%.

[0075] The 808nm application requirements are processed as the initial arrangement to obtain the following Figure 3 The arrangement effect on the left is shown. The 940nm arrangement is written into the system through programming. The horizontal displacement adjustment of 8 types of nanopillars can be achieved through MEMS control. The nanopillar arrangement after adjustment is as follows Figure 3 As shown on the right, in summary, this method can meet the application requirements of both 808nm and 940nm scenarios.

[0076] The above are only specific embodiments of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A metalens device with adjustable microstructure, characterized in that: The invention comprises a super lens and a MEMS actuator (3), wherein the super lens is suspended on the MEMS actuator (3); the super lens comprises a microstructure (1) and a substrate (2), wherein the microstructure (1) is arranged above the substrate (2).

2. The superlens device according to claim 1, wherein: The size of the MEMS actuator (3) is the same as that of the substrate (2), the MEMS actuator (3) is connected to the substrate (2), and the middle of the MEMS actuator (3) is hollowed out.

3. The superlens device according to claim 1, wherein: The scale of the microstructure (1) is in the nanometer-micrometer order, and the arrangement period is less than half of the incident wavelength.

4. The superlens device according to claim 1, wherein: The phase distribution formula of the microstructure (1) is as follows: Where λ is the wavelength, x and y are the coordinates of the metalens, and f is the focal length of the metalens.

5. The superlens device according to claim 1, wherein: The super lens is a transmission type and modulates the light beam by using a propagation phase.

6. The superlens device according to claim 1, wherein: The shape of the substrate (2) is square; the shape of the microstructure (1) is centrally symmetrical.

7. The superlens device according to claim 6, wherein: The shape of the microstructure (1) is circular or square.

8. The superlens device according to claim 1, wherein: The MESMS actuator (3) is driven by electromagnetic, current or voltage.

9. A method for designing a superlens device, characterized in that: The steps include: S1. Determine application requirements and optical design According to specific application requirements, optical design software is used to perform optical design and generate the phase distribution of specific metalens under different application requirements; S2, FDTD simulation S21. Select a suitable microstructure and substrate, and simulate the relationship between the geometric dimensions of the microstructure and the phase and transmittance. S22, divide the microstructure phase 2π after the simulation into N equal parts, and find the microstructure closest to the corresponding phase. The phase division formula is as follows: in is the phase interval, N is the type of microstructure, the more types of N, the more continuous the phase; S23. Screen out the microstructure size suitable for specific application requirements while ensuring that its transmittance and phase can cover all application wavelength requirements; S3. Microstructure arrangement According to application requirements, the screened microstructure units are arranged to obtain different arrangements; S4. Fabrication of superlens Choose one of the application requirement arrangements to make a metalens; S5, Programming and MEMS Drive Program and store the arrangement methods for different applications obtained by FDTD simulation.

10. The method for designing a metalens with adjustable microstructure according to claim 9, wherein: By triggering the adjustment of the MEMS-driven microstructure, new microstructure arrangements can be generated to meet new application requirements.

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