WO2023216472A1 - Procédé de régulation de la plage de longueur focale d'une super-lentille à focale variable par introduction d'une phase supplémentaire - Google Patents

Procédé de régulation de la plage de longueur focale d'une super-lentille à focale variable par introduction d'une phase supplémentaire Download PDF

Info

Publication number
WO2023216472A1
WO2023216472A1 PCT/CN2022/116987 CN2022116987W WO2023216472A1 WO 2023216472 A1 WO2023216472 A1 WO 2023216472A1 CN 2022116987 W CN2022116987 W CN 2022116987W WO 2023216472 A1 WO2023216472 A1 WO 2023216472A1
Authority
WO
WIPO (PCT)
Prior art keywords
zoom
phase
focal length
hyperlens
length range
Prior art date
Application number
PCT/CN2022/116987
Other languages
English (en)
Chinese (zh)
Inventor
沈哲
伍资哈
王淼
何全
Original Assignee
南京理工大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 南京理工大学 filed Critical 南京理工大学
Publication of WO2023216472A1 publication Critical patent/WO2023216472A1/fr

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0081—Simple or compound lenses having one or more elements with analytic function to create variable power
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/02—Simple or compound lenses with non-spherical faces

Definitions

  • the invention belongs to the field of optical zoom, and in particular relates to a method for controlling the focal length range of a zoom hyperlens by introducing an additional phase.
  • Tunable optics especially tunable lenses with variable refractive power
  • Tunable optics have indispensable applications in many optical systems, such as imaging systems for simulating the functions of the human eye, or for tunable illumination and beam control.
  • adjustable focal length including liquid polymer containers and liquid crystal lens groups.
  • these focusing methods require complex optical systems composed of many optical devices to complete. They are large in size and are not conducive to integration.
  • Metasurfaces ultrathin two-dimensional artificial structures composed of metallic or dielectric optical subwavelength antennas for wavefront modulation, have attracted widespread research interest in recent years. By designing appropriate sub-wavelength structures, metasurfaces can achieve arbitrary control of the phase, amplitude, and polarization state of incident light.
  • metasurface-based devices have been proposed for structural design, such as holograms, deflectors, and wave plates. Due to their advantages of small size, good integration with semiconductor devices, and high degree of design freedom, metasurfaces are used to solve problems of traditional geometric optical components, such as chromatic aberration and monochromatic aberration. Metasurfaces are also widely used in adjusting the focal length of lenses.
  • thermal modulation of metalens exploits the response to temperature by changing the complex refractive index that affects the phase shift and its phase distribution.
  • a thermally tunable metalens uses a spiral gold heater to adjust the temperature increase; the refractive index changes with temperature, depending on the thermal coefficient dn/dT.
  • Such tunable lenses that exploit both electrically and thermally mediated phenomena are classified as electrothermal optical systems.
  • electrically tunable metalens the phase shift is obtained via bias voltage.
  • the design of field-effect-induced tunable metallic materials takes advantage of the proportional increase in the complex permittivity of elementary atoms with carrier concentration.
  • a lens with tunable NA and focal length is proposed, which exploits the change in carrier density under the action of an electric field; the advantage of this lens is that this change does not require a change in shape and the tuning speed is faster than that of a thermally tunable lens quick.
  • Mechanical stimulation of the optical system induces structural changes that affect the position, size, and shape of the focal point. These stimuli include electrostatic actuation, rotation, and stretching.
  • thermal modulation and electrical tuning require additional control systems.
  • mechanically modulated metalens devices have fast tuning speed and simple modulation methods, making them more suitable for imaging applications in mobile electronic devices.
  • the above-mentioned polarization-insensitive zoom metalens has low light utilization efficiency when the relative angle of the doublet metasurface is large, so the focusing efficiency is low.
  • the object of the present invention is to provide a method for controlling the focal length range of a zoom hyperlens by introducing additional phases.
  • the technical solution to achieve the object of the present invention is: a method for regulating the focal length range of a zoom hyperlens by introducing an additional phase.
  • the zoom hyperlens includes two layers of glass as a base, and a lens for adjusting the phase provided on the upper surface of the glass.
  • the two-layer dielectric cylindrical layer array, the zoom metalens constructs a metasurface according to the relationship between the micro-nano dielectric cylindrical unit structure radius and phase change. Its phase formula is superimposed by the actual lens phase and the additional phase.
  • the additional phase is added by adding a constant phase Compensation is used to control the focal length range.
  • the zoom hyperlens used arranges an array of micro-nano dielectric cylindrical layers on a planar substrate to realize the function of a traditional zoom hyperlens, and can minimize its thickness to the wavelength order of magnitude, making it easy to integrate into complex systems or chip-based micro systems; 2)
  • the complex beam modulation of the zoom metalens can be achieved by the phase superposition principle. This processing can simplify the optical system originally composed of multiple optical elements. to a metasurface thin sheet, further reducing the volume of the optical system;
  • the zoom hyperlens used has polarization insensitivity and can change the focal length for incident light of different polarizations, which breaks away from the previously common geometric phase hyperlens.
  • the surface has specific requirements on the polarization of the incident light, and can effectively reduce the efficiency loss caused by the polarization conversion of the geometric phase metasurface; 4)
  • the present invention can realize a zoom hyperlens with adjustable focal length and has good flexibility; 5 )
  • the focal length change is achieved by rotating two metasurfaces.
  • This method provides a direct wavefront control method based on metasurfaces for lens zoom, and provides a new possibility for the application of structured beams; 6) Above guarantee In the case of the above capabilities, an additional phase is added, which can change the focus control range and make the focus control more flexible.
  • Figure 1 is a schematic structural diagram of an optical zoom metalens based on a polarization-insensitive metasurface in one embodiment.
  • Figure 2 is a schematic diagram of the structure of a metasurface unit in one embodiment.
  • Figure 3 is a normalized magnetic energy density diagram of two adjacent nanopillars with a radius of 80 nm in one embodiment.
  • the white lines in the figure represent the boundaries of the structure.
  • Figure 4 is a diagram showing the relationship between the radius of the metasurface unit structure, the phase change amount and the efficiency under x-polarization, y-polarization, left-handed circular polarization and right-handed circular polarization obtained by performing a simulation scan on the metasurface unit structure in Figure 2 in one embodiment. .
  • Figure 5 is a diagram of the simulation results after applying a round function to the optical zoom metalens of the polarization-insensitive metasurface in an embodiment, wherein Figures 5(a) to (d) are 40°, 80°, 120° and 160° focus diagram, Figure 5 (e) ⁇ (h) are their phase distribution diagrams respectively.
  • Figure 6 is a graph of focus at different angles in one embodiment.
  • Figure 7 is a schematic diagram of focus points under different polarized lights in one embodiment.
  • Figures 7(a) to (d) are respectively the results of focusing using linearly polarized light, X-polarized light, Y-polarized light and circularly polarized light at a rotation angle of 100°.
  • FIG. 8 is a schematic diagram of the focus and phase corresponding to the four angles in FIG. 5 after adding an additional phase of 120° in an embodiment.
  • Figures 8(a) ⁇ (d) are focus diagrams of -80°, -40°, 0° and 40° respectively, and
  • Figures 8(e) ⁇ (h) are their phase distribution diagrams respectively.
  • Figure 9 is a schematic diagram of focusing efficiency, which is divided into four situations, with or without round function and whether to add 120° additional phase, and a comparison chart of the efficiency in various situations at three different focal lengths of 16.5um, 23um, and 34um.
  • a method for regulating the focal length range of a zoom hyperlens by introducing an additional phase includes two layers of glass as a base, and a two-layer dielectric cylinder disposed on the upper surface of the glass for adjusting the phase.
  • Layer array characterized in that the zoom metalens constructs a metasurface according to the relationship between the micro-nano dielectric cylindrical unit structure radius and phase change, and its phase formula is characterized in that it can be superimposed by the actual lens phase and the additional phase; the additional phase is added by adding a constant Phase compensation is used to control the focus range, making focus control more flexible.
  • the dielectric material used in the cylindrical structure should meet the condition that the real part of the refractive index is large (reaching more than 1.5 times the base refractive index) and the imaginary part is close to 0 within the working wavelength.
  • the micro-nano cylindrical structure layer is an array of nano-cylinders with different radii.
  • the geometric parameters of the cylindrical unit structure (as shown in Figure 2) need to meet the following restrictions: According to Nyquist sampling Law, the lattice constant p should be less than ⁇ /2NA, ⁇ is the wavelength, NA is the numerical aperture of the hyperlens, and at the same time, in order to ensure that there is only 0th order diffraction at normal incidence, p should be less than the equivalent working wavelength of the incident light in the substrate ( ⁇ /n L1 ) is greater than the diffraction condition ( ⁇ /2n L1 ), n L1 is the substrate refractive index.
  • the minimum value of the radius r of the cylindrical unit structure depends on the manufacturing process, and the maximum value thereof cannot be greater than half of the lattice constant.
  • the height h of the cylindrical unit structure should be greater than ⁇ /(n M1 -1), where n M1 is the refractive index of the nanocolumn material.
  • the phase change should cover 0 to 2 ⁇ .
  • the radius-phase change and radius-transmission efficiency change curves of the cylindrical unit structure obtained by scanning the radius should be polarization insensitive, that is, the radius-phase change curves measured under different polarizations should be consistent.
  • the radius-transmission efficiency change curve measured under polarization should be consistent.
  • Scattering from zoom metalensing nanostructures should be a local effect, with no coupling between nanostructures.
  • the zoom hyperlens is polarization insensitive, that is, for incident light of different polarization states, the zoom hyperlens can focus without changing the focal position.
  • a polarization-insensitive zoom metalens based on a double-layer metasurface is provided.
  • the zoom metalens includes double-layer glass L1 and L2 as a base, and is disposed on the upper surface of the glass.
  • the two-layer micro-nano dielectric cylindrical layer arrays M1 and M2 are used to adjust the phase.
  • micro-nano dielectric cylindrical structure layers M1 and M2 are used to realize the phase control function and are respectively arranged on the glasses L1 and L2.
  • the incident light is vertically irradiated on the lower surface of the first layer of L2 glass substrate.
  • the second layer of L1 metasurface is rotated, and the focal length changes.
  • the focal length range can be adjusted by adding a deflection phase.
  • TiO 2 is selected as the cylindrical material.
  • the refractive index of TiO 2 has a large real part and a negligible imaginary part. Therefore, it has a high refractive index and is almost Negligible absorption losses.
  • the height h of the TiO 2 cylinder is selected to be 600 nm, and the lattice constant p is 300 nm.
  • the relationship between the phase and transmission efficiency of the TiO 2 cylindrical unit structure and the radius of the TiO 2 cylinder can be obtained by performing FDTD simulation scanning on the TiO 2 cylindrical unit structure (as shown in Figure 2). Since the coupling between adjacent nanopillars is extremely weak (as shown in Figure 3), they can be considered to independently perform phase control, so the changes in radius and transmission efficiency can be obtained by scanning the radius of the nanopillars.
  • periodic boundary conditions are used in the x and y directions, and PML boundary conditions are used in the z direction.
  • a point monitor is set up at 80 ⁇ m on the upper surface of the substrate to obtain changes in phase and transmission efficiency.
  • phase, transmission efficiency and radius The relationship between phase, transmission efficiency and radius is measured under the incidence of x-polarized, y-polarized, left-handed circularly polarized, and right-handed circularly polarized plane waves as shown in the figure below 4 shown. It can be seen that for different polarizations, the relationship between phase, transmission efficiency and radius is consistent, which illustrates that the unit structure has polarization insensitivity.
  • the nanocolumn changes in the range of 40nm to 110nm the phase change covers 0 to 2 ⁇ .
  • the transmission efficiency is above 80%.
  • the above results show that by changing the radius of the nanopillar in the range of 40nm to 110nm, high-efficiency phase control of arbitrary polarization can be achieved.
  • the metasurface can be designed according to the phase formula through the above method.
  • Formulas (1) and (2) respectively represent the transmission functions of the two phase plates.
  • Formula (3) is the transmission of the phase plate corresponding to formula (2) after being rotated by an angle ⁇ . function.
  • Formula (4) is the total transmission function after superposition of two phase plates.
  • the focal length of the designed zoom lens can be obtained as formula (5). It can be seen that the focal length f is a function of ⁇ , and the focal length can be changed by changing the rotation angle of the second super lens, thereby achieving the zoom function.
  • Equations (6) and (7) are respectively the transmission functions of two phase plates after adding additional phases, which can add the function of additional phases.
  • the Moiré superlens structure can be obtained by formula (1) (2) (3) (4)
  • the focal length can be obtained by formula (5)
  • the Moiré after adding additional phase can be obtained by formula (6) (7).
  • Metalens structure
  • T com T 1 (r, ⁇ )T 2
  • rot (r, ⁇ ) exp[i ⁇ round(ar 2 ) (4)
  • ⁇ represents the working wavelength, which is 532nm in this embodiment
  • r is the radius from any point to the center of the phase plate
  • ⁇ is the angle between the x-axis and the axis at the center of the point
  • f is the focal length
  • ⁇ is the lens
  • the rotation angle, a and b are constants, are limited by the resolution of the metalens, and depend on the pixel size and the maximum radius of the metalens
  • C is the unit cell size of the nanobrick structure
  • rmax is the radius of the GEMS. According to the corresponding phase formula, a hyperlens for zoom can be made.
  • the production process of the optical zoom metalens based on the polarization-insensitive metasurface of the present invention is as follows: coating a flat silicon dioxide surface with hexamethyldisilazane to promote resist adhesion, and then rotating and plating undiluted Positive electron beam anti-corrosion agent ZEP-520A film to obtain an anti-corrosion material coating with a thickness of 600nm.
  • the anti-corrosion agent is then baked at 180°C for 5 minutes.
  • the samples were then coated with 10 nm of chromium via electron beam evaporation to avoid charging effects during the writing process.
  • the inverted metasurface pattern was etched into the anti-corrosion coating by exposing the pattern to an accelerating voltage of 125 kV and gently stirring in o-xylene for 60 seconds to visualize the pattern.
  • the system is then placed in a N flow and TiO 2 is deposited by atomic layering technology at 90°C using tetrakis(dimethylamino)titanium as the precursor.
  • the film thickness produced by complete deposition of TiO 2 should be greater than the maximum feature size width . half, that is, 600nm.
  • the top of the TiO2 metasurface and residual corrosion inhibitor are exposed.
  • the sample was exposed to UV radiation and ozone, and soaked in a remover for 24 hours to obtain the final dielectric metasurface.
  • FDTD simulation verification is performed on the optical zoom metalens based on the polarization-insensitive metasurface of the present invention.
  • the process is as follows:
  • the setting parameters are: silica glass layer, specification is 20 ⁇ m*20 ⁇ m, thickness 0.5 ⁇ m; simulation wavelength 532nm; metasurface unit cylinder, thickness 0.6 ⁇ m, lattice constant 0.3 ⁇ m.
  • Figure 8 is a schematic diagram of the focus and phase after adding an additional phase of 120°. It can be seen that the focus position and phase are not affected at the corresponding angle, but a large angle can be converted into a small angle to flexibly control the focus range.
  • FIG. 9 is a schematic diagram of focal length and focusing efficiency. Focusing efficiency is defined as the total power in a circular area with a diameter of 2 ⁇ FWHM and the total power in a circular area with a diameter of 1mm in the focal plane. The center of the two circular areas is the point of maximum intensity. It can be seen from Figure 9 that the additional phase has a certain effect on improving the focusing efficiency and can maintain a relatively high efficiency within the desired focal length range.
  • the optical zoom metalens used in the present invention is a two-dimensional array metasurface made of micro-nano dielectric cylinders on a substrate. It can control the optical wavefront at sub-wavelength spatial resolution and has a complete phase control function to achieve lens zoom. Its polarization-insensitive feature allows it to achieve zooming of the lens for incident light of any polarization, which is very different from the previous common PB phase-based incident light that requires a specific polarization state.
  • the designed zoom metalens has potential applications in the field of super-resolution imaging. This optical zoom metalens based on polarization-insensitive metasurfaces can be easily combined into chips to form composite devices with expanded functionality.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Polarising Elements (AREA)

Abstract

Divulgué dans la présente invention est un procédé de régulation d'une plage de longueur focale d'une super-lentille à focale variable par l'introduction d'une phase supplémentaire. Une super-lentille comprend : deux couches de verre servant de substrats, et deux couches de réseaux de couches de pilier diélectrique disposées respectivement sur les substrats de verre. Lorsque la super-lentille fonctionne, la lumière incidente irradie verticalement la surface inférieure du substrat de verre au niveau de la première couche, la focalisation est mise en œuvre au moyen de la transmission du verre et de la modulation de phase des réseaux de nanopiliers de silicium diélectrique, une super-surface au niveau de la seconde couche est tournée, la longueur focale est modifiée, et une plage de longueur focale peut être régulée au moyen d'une phase de déviation supplémentaire. Selon la super-lentille à focale variable à double couche pourvue en outre de la phase de déviation proposée par la présente invention, la contradiction entre les grands angles de rotation et l'efficacité des lentilles à focale variable classiques est résolue ; dans la présente invention, une micro-nanostructure est utilisée pour améliorer les modes de zoom classiques, la taille et le poids de la lentille sont réduits autant que possible, et la tendance de miniaturisation et d'intégration de dispositifs optiques modernes ou de dispositifs photoélectriques est satisfaite.
PCT/CN2022/116987 2022-05-10 2022-09-05 Procédé de régulation de la plage de longueur focale d'une super-lentille à focale variable par introduction d'une phase supplémentaire WO2023216472A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202210503690.7A CN114815009A (zh) 2022-05-10 2022-05-10 通过引入附加相位调控变焦超透镜焦距范围的方法
CN202210503690.7 2022-05-10

Publications (1)

Publication Number Publication Date
WO2023216472A1 true WO2023216472A1 (fr) 2023-11-16

Family

ID=82512671

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/116987 WO2023216472A1 (fr) 2022-05-10 2022-09-05 Procédé de régulation de la plage de longueur focale d'une super-lentille à focale variable par introduction d'une phase supplémentaire

Country Status (2)

Country Link
CN (1) CN114815009A (fr)
WO (1) WO2023216472A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115113308A (zh) * 2022-07-06 2022-09-27 重庆大学 一种具有角放大功能的超分辨成像透镜

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114815009A (zh) * 2022-05-10 2022-07-29 南京理工大学 通过引入附加相位调控变焦超透镜焦距范围的方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109901251A (zh) * 2019-04-14 2019-06-18 桂林电子科技大学 一种基于多层石墨烯的双焦点与长焦深超透镜
CN110161676A (zh) * 2019-05-31 2019-08-23 华中科技大学 一种基于双层介质超表面的光学变焦系统
CN110412761A (zh) * 2018-05-08 2019-11-05 武汉大学 一种基于超表面材料的多档静态变焦透镜
CN112255711A (zh) * 2020-10-26 2021-01-22 武汉邮电科学研究院有限公司 一种用于产生柱矢量光束的连续变焦透镜及其设计方法
CN114815009A (zh) * 2022-05-10 2022-07-29 南京理工大学 通过引入附加相位调控变焦超透镜焦距范围的方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109212741B (zh) * 2018-10-31 2021-08-03 武汉邮电科学研究院有限公司 一种连续变焦透镜及光学系统
CN110376731B (zh) * 2019-07-13 2021-10-08 南京理工大学 基于多层超构表面的宽带消色差超构透镜组的构建方法
CN111948805B (zh) * 2020-07-06 2022-07-19 中山大学 一种可实现坐标变换的超表面组及其超表面的制备方法
CN112147721B (zh) * 2020-09-11 2021-06-04 武汉大学 偏振阶数可调且可连续变焦的柱矢量光束透镜及构造方法
CN114296155B (zh) * 2021-12-02 2023-02-07 华中科技大学 一种基于双层介质超表面的宽谱光学变焦系统

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110412761A (zh) * 2018-05-08 2019-11-05 武汉大学 一种基于超表面材料的多档静态变焦透镜
CN109901251A (zh) * 2019-04-14 2019-06-18 桂林电子科技大学 一种基于多层石墨烯的双焦点与长焦深超透镜
CN110161676A (zh) * 2019-05-31 2019-08-23 华中科技大学 一种基于双层介质超表面的光学变焦系统
CN112255711A (zh) * 2020-10-26 2021-01-22 武汉邮电科学研究院有限公司 一种用于产生柱矢量光束的连续变焦透镜及其设计方法
CN114815009A (zh) * 2022-05-10 2022-07-29 南京理工大学 通过引入附加相位调控变焦超透镜焦距范围的方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115113308A (zh) * 2022-07-06 2022-09-27 重庆大学 一种具有角放大功能的超分辨成像透镜
CN115113308B (zh) * 2022-07-06 2024-05-14 重庆大学 一种具有角放大功能的超分辨成像透镜

Also Published As

Publication number Publication date
CN114815009A (zh) 2022-07-29

Similar Documents

Publication Publication Date Title
WO2023216472A1 (fr) Procédé de régulation de la plage de longueur focale d'une super-lentille à focale variable par introduction d'une phase supplémentaire
Hsiao et al. Fundamentals and applications of metasurfaces
Zhang et al. Plasmonic metasurfaces for switchable photonic spin–orbit interactions based on phase change materials
US9507064B2 (en) Dielectric metasurface optical elements
CN109061780B (zh) 一种双波长同轴独立聚焦的超表面透镜
AU2011281097B2 (en) Nano-optic refractive optics
CN104749665B (zh) 基于介质材料的平面透镜单元、平面透镜及制备方法
US20210041609A1 (en) Diffraction grating comprising double-materials structures
Li et al. Active all-dielectric bifocal metalens assisted by germanium antimony telluride
CN112987290A (zh) 一种可见光消色差超构透镜及其制备方法
Kou et al. Terahertz switchable focusing planar lens with a nanoscale vanadium dioxide integrated metasurface
Ahmed et al. Strain‐Multiplex Metalens Array for Tunable Focusing and Imaging
CN112882133A (zh) 一种产生艾里光束的几何相位型超透镜
Guo et al. Superlens-enhanced laser interference lithography
CN111948806B (zh) 超构表面彩虹系统的设计与实现方法
Shao et al. Metalenses based on the non-parallel double-slit arrays
CN105700073A (zh) 一种表面等离激元单向耦合和分束器件及制备方法
CN108535881B (zh) 具有超表面的钙钛矿天线及其制备方法
CN113376869B (zh) 一种环形孔径式几何相位型超表面光学针发生器
CN115598741A (zh) 一种基于光学相变材料的多阱光镊超透镜
CN214470399U (zh) 基于石墨烯相位梯度超表面的全极化隐身地毯
CN114764156B (zh) 一种红外全介质正交柱面超透镜
Yuan et al. Surface-nanostructured Al–AlN composite thin films with excellent broad-band antireflection properties fabricated by limited reactive sputtering
Juneja et al. Fabrication of innovative diffraction gratings for light absorption enhancement in silicon thin films for solar cell application
Zhao et al. Multi-focusing metalenses based on quadrangular frustum pyramid-shaped nanoantennas

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22941413

Country of ref document: EP

Kind code of ref document: A1