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Choi T, Choi C, Bang J, Kim Y, Son H, Kim C, Jang J, Jeong Y, Lee B. Multiwavelength Achromatic Deflector in the Visible Using a Single-Layer Freeform Metasurface. NANO LETTERS 2024; 24:10980-10986. [PMID: 39192436 DOI: 10.1021/acs.nanolett.4c02995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
Deflectors are essential for modulating beam direction in optical systems but often face form factor issues or chromatic aberration with conventional optical elements, such as prisms, mirrors, and diffractive/holographic optical elements. Despite recent efforts to address such issues using metasurfaces, their practicality remains limited due to operation wavelengths in the near-infrared or the fabrication difficulties inherent in the multilayer scheme. Here, we propose a novel single-layer metasurface achieving multiwavelength chromatic aberration-free deflection across the visible spectrum by employing the robust freeform design strategy to simplify the fabrication process. By properly selecting diffraction orders for red, green, and blue wavelengths to achieve identical wavelength-diffraction-order products, the metasurface deflects light at a consistent angle of 41.3° with a high efficiency. The coupled Bloch mode analysis explains the physical properties, and experimental fabrication and characterization confirm its effectiveness. This approach holds potential for various applications such as AR/VR, digital cameras, and high-quality optical systems.
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Affiliation(s)
- Taewon Choi
- Inter-University Semiconductor Research Center, School of Electrical and Computer Engineering, Seoul National University, 1 Gwanakro, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Chulsoo Choi
- Inter-University Semiconductor Research Center, School of Electrical and Computer Engineering, Seoul National University, 1 Gwanakro, Gwanak-Gu, Seoul 08826, Republic of Korea
- System LSI Division, Samsung Electronics Co., Ltd, Samsung-ro 1, Giheung-gu, Yongin-si, Gyeonggi-do 17113, Republic of Korea
| | - Junseo Bang
- Inter-University Semiconductor Research Center, School of Electrical and Computer Engineering, Seoul National University, 1 Gwanakro, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Youngjin Kim
- Inter-University Semiconductor Research Center, School of Electrical and Computer Engineering, Seoul National University, 1 Gwanakro, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Hyunwoo Son
- Inter-University Semiconductor Research Center, School of Electrical and Computer Engineering, Seoul National University, 1 Gwanakro, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Changhyun Kim
- Inter-University Semiconductor Research Center, School of Electrical and Computer Engineering, Seoul National University, 1 Gwanakro, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Junhyeok Jang
- Inter-University Semiconductor Research Center, School of Electrical and Computer Engineering, Seoul National University, 1 Gwanakro, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Yoonchan Jeong
- Inter-University Semiconductor Research Center, School of Electrical and Computer Engineering, Seoul National University, 1 Gwanakro, Gwanak-Gu, Seoul 08826, Republic of Korea
| | - Byoungho Lee
- Inter-University Semiconductor Research Center, School of Electrical and Computer Engineering, Seoul National University, 1 Gwanakro, Gwanak-Gu, Seoul 08826, Republic of Korea
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Badloe T, Yang Y, Lee S, Jeon D, Youn J, Kim DS, Rho J. Artificial Intelligence-Enhanced Metasurfaces for Instantaneous Measurements of Dispersive Refractive Index. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2403143. [PMID: 39225343 DOI: 10.1002/advs.202403143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 07/13/2024] [Indexed: 09/04/2024]
Abstract
Measurements of the refractive index of liquids are in high demand in numerous fields such as agriculture, food and beverages, and medicine. However, conventional ellipsometric refractive index measurements are too expensive and labor-intensive for consumer devices, while Abbe refractometry is limited to the measurement at a single wavelength. Here, a new approach is proposed using machine learning to unlock the potential of colorimetric metasurfaces for the real-time measurement of the dispersive refractive index of liquids over the entire visible spectrum. The platform with a proof-of-concept experiment for measuring the concentration of glucose is further demonstrated, which holds a profound impact in non-invasive medical sensing. High-index-dielectric metasurfaces are designed and fabricated, while their experimentally measured reflectance and reflected colors, through microscopy and a standard smartphone, are used to train deep-learning models to provide measurements of the dispersive background refractive index with a resolution of ≈10-4, which is comparable to the known index as measured with ellipsometry. These results show the potential of enabling the unique optical properties of metasurfaces with machine learning to create a platform for the quick, simple, and high-resolution measurement of the dispersive refractive index of liquids, without the need for highly specialized experts and optical procedures.
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Affiliation(s)
- Trevon Badloe
- Graduate School of Artificial Intelligence, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Department of Electronics and Information Engineering, Korea University, Sejong, 30019, Republic of Korea
| | - Younghwan Yang
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Seokho Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Dongmin Jeon
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jaeseung Youn
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Dong Sung Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Junsuk Rho
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics, Pohang, 37673, Republic of Korea
- National Institute of Nanomaterials Technology (NINT), Pohang, 37673, Republic of Korea
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Ansari MA, Ahmed H, Li Y, Wang G, Callaghan JE, Wang R, Downing J, Chen X. Multifaceted control of focal points along an arbitrary 3D curved trajectory. LIGHT, SCIENCE & APPLICATIONS 2024; 13:224. [PMID: 39223113 PMCID: PMC11369200 DOI: 10.1038/s41377-024-01565-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 07/26/2024] [Accepted: 08/04/2024] [Indexed: 09/04/2024]
Abstract
Metalenses can integrate the functionalities of multiple optical components thanks to the unprecedented capability of optical metasurfaces in light control. With the rapid development of optical metasurfaces, metalenses continue to evolve. Polarization and color play a very important role in understanding optics and serve as valuable tools for gaining insights into our world. Benefiting from the design flexibility of metasurfaces, we propose and experimentally demonstrate a super metalens that can realize multifaceted control of focal points along any 3D curved trajectory. The wavelengths and polarization states of all focal points are engineered in a desirable manner. The super metalens can simultaneously realize customized 3D positioning, polarization states, and wavelengths of focal points, which are experimentally demonstrated with incident wavelengths ranging from 501 to 700 nm. We further showcase the application of the developed super metalenses in 3D optical distance measurement. The compact nature of metasurfaces and unique properties of the proposed super metalenses hold promise to dramatically miniaturize and simplify the optical architecture for applications in optical metrology, imaging, detection, and security.
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Affiliation(s)
- Muhammad Afnan Ansari
- Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Hammad Ahmed
- Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Yan Li
- School of Materials, Zhengzhou University of Aeronautics, Zhengzhou, 450015, China
| | - Guanchao Wang
- Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
- School of Physics, Harbin Institute of Technology, Harbin, 150001, China
| | - Jemma E Callaghan
- Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
- STMicroelectronics, 1Tanfield, Inverleith Row, Edinburgh, EH3 5DA, UK
| | - Ruoxing Wang
- Department of Mathematics and Physics, North China Electric Power University, Baoding, 071003, China
| | - James Downing
- STMicroelectronics, 1Tanfield, Inverleith Row, Edinburgh, EH3 5DA, UK
| | - Xianzhong Chen
- Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
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Zeng J, Zhang J, Dong Y, Wang J. Full-Dimensional Geometric-Phase Spatial Light Metamodulation. NANO LETTERS 2024. [PMID: 38949164 DOI: 10.1021/acs.nanolett.4c01665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Full-dimensional spatial light modulation requires simultaneous, arbitrary, and independent manipulation of the spatial phase, amplitude, and polarization. This is crucial for leveraging the complete physical dimension resources of light. However, full-dimensional metamodulation can be challenging due to the need for multiple independent control factors. To address this challenge, here we propose parallel-tasking metasurfaces to enable full-dimensional spatial light metamodulation based fully on the geometric-phase concept. Indeed, the meta-atoms are divided into several subphases, each of which serves as an independent control factor to manipulate light phase, amplitude, and polarization through geometric phase, interference, and orthogonal polarization superposition, respectively. Therefore, the macroscopic group of meta-atoms leads to metasurfaces that can achieve broadband full-dimensional spatial light metamodulation, as demonstrated by various types of structured light generation. This approach paves the way to future wide applications of light manipulation enabled by full-dimensional spatial light metamodulation.
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Affiliation(s)
- Jinwei Zeng
- Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074 Hubei, China
- Optics Valley Laboratory, Wuhan, 430074 Hubei, China
| | - Jinrun Zhang
- Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074 Hubei, China
- Optics Valley Laboratory, Wuhan, 430074 Hubei, China
| | - Yajuan Dong
- Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074 Hubei, China
- Optics Valley Laboratory, Wuhan, 430074 Hubei, China
| | - Jian Wang
- Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074 Hubei, China
- Optics Valley Laboratory, Wuhan, 430074 Hubei, China
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5
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Gu M, Ma L, Cui G, Zhang Z, Zhan Z, Zhou Y, Gao S, Choi DY, Cheng C, Liu C. Multichannel focused higher-order Poincaré sphere beam generation based on a dielectric geometric metasurface. OPTICS EXPRESS 2024; 32:18958-18971. [PMID: 38859041 DOI: 10.1364/oe.521681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/28/2024] [Indexed: 06/12/2024]
Abstract
Focused vector beams (VBs) are important topic in the areas of light field manipulation. Geometric metasurfaces provide a convenient platform to facilitate the generation of focused VBs. In this study, we propose a dielectric geometric metasurface to generate multichannel focused higher-order Poincaré sphere (HOP) beams. With identical meta-atoms of half-wave plate, the metasurface comprises two sub-metasurfaces, and each of them includes two sets of rings related to Fresnel zones. For meta-atoms on each set of rings, the hyperbolic geometric phase profile is configured so that the mirror-symmetrical position-flip of the off-axis focal point is enabled under the chirality switch of the illuminating circular polarization. With the design of helical geometric phase profiles for the two sets of rings, a sub-metasurface generate two HOP beams at the symmetrical two focal points. The performance of the two sub-metasurfaces enables the metasurface with four sets of rings to generate the array of four HOP beams. The proposed method was validated by theoretical analyses, numerical simulation and experimental conduction. This research would be significant in miniaturizing and integrating optical systems involving applications of VB generations and applications.
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Wang B, Wei R, Shi H, Bao Y. Dynamic Spatial-Selective Metasurface with Multiple-Beam Interference. NANO LETTERS 2024; 24:5886-5893. [PMID: 38687301 DOI: 10.1021/acs.nanolett.4c01254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
The emergence of the metasurface has provided a versatile platform for the manipulation of light at the nanoscale. Recent research in metasurfaces has explored a plethora of dynamic control and switching of multifunctionalities, paving the way for innovative applications in fields such as imaging, sensing, and communication. However, current dynamic multifunctional metasurfaces face challenges in terms of functional scalability and selective activation. In this work, we introduce and experimentally demonstrate a strategy that utilizes multiple plane waves to create arbitrary periodic patterns on the metasurface, thus enabling the dynamic and arbitrary spatial-selective activation of its embedded multiplexed functionalities. Furthermore, our strategy facilitates dynamic light control through mechanical translation, as demonstrated by a high-speed, dynamically switchable beam deflection scenario. Our method effectively overcomes the limitations associated with traditional spatially multiplexing techniques, offering greater flexibility and selectivity for dynamic control in multifunctional metasurfaces.
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Affiliation(s)
- Boyou Wang
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 511443, China
| | - Rui Wei
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 511443, China
| | - Hongsheng Shi
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 511443, China
| | - Yanjun Bao
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou 511443, China
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7
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Tang P, Kim Y, Badloe T, Xiao L, Yang Y, Kim M, Rho J, Li G. Polarization-independent edge detection based on the spin-orbit interaction of light. OPTICS EXPRESS 2024; 32:17560-17570. [PMID: 38858937 DOI: 10.1364/oe.521661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/16/2024] [Indexed: 06/12/2024]
Abstract
In previous edge detection schemes based on the spin-orbit interaction of light, the direction and intensity of the edge-enhanced images are influenced by the incident polarization state. In this study, we develop an edge detection strategy that is insensitive to changes in both the incident polarization and the incident angle. The output intensity and transfer function remain entirely impervious to changes in incident polarization, being explicitly formulated as functions of the incident angle, specifically in terms of cot 2θ i and cotθ i , respectively. This behavior is attributed to the opposing nature of the polarization components E~r H-H and E~r V-V in the x-direction after undergoing mapping through the Glan polarizer, while the sum of polarization components E~r H-V and E~r V-H in the y-direction can be simplified to terms independent of incident polarization. Furthermore, we propose a metasurface design to achieve the required optical properties in order to realize the derived edge detection scheme.
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Kang H, Oh D, Jeon N, Kim J, Kim H, Badloe T, Rho J. Tailoring high-refractive-index nanocomposites for manufacturing of ultraviolet metasurfaces. MICROSYSTEMS & NANOENGINEERING 2024; 10:53. [PMID: 38654843 PMCID: PMC11035676 DOI: 10.1038/s41378-024-00681-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 02/09/2024] [Accepted: 02/19/2024] [Indexed: 04/26/2024]
Abstract
Nanoimprint lithography (NIL) has been utilized to address the manufacturing challenges of high cost and low throughput for optical metasurfaces. To overcome the limitations inherent in conventional imprint resins characterized by a low refractive index (n), high-n nanocomposites have been introduced to directly serve as meta-atoms. However, comprehensive research on these nanocomposites is notably lacking. In this study, we focus on the composition of high-n zirconium dioxide (ZrO2) nanoparticle (NP) concentration and solvents used to produce ultraviolet (UV) metaholograms and quantify the transfer fidelity by the measured conversion efficiency. The utilization of 80 wt% ZrO2 NPs in MIBK, MEK, and acetone results in conversion efficiencies of 62.3%, 51.4%, and 61.5%, respectively, at a wavelength of 325 nm. The analysis of the solvent composition and NP concentration can further enhance the manufacturing capabilities of high-n nanocomposites in NIL, enabling potential practical use of optical metasurfaces.
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Affiliation(s)
- Hyunjung Kang
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Dongkyo Oh
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Nara Jeon
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Joohoon Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Hongyoon Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Trevon Badloe
- Graduate School of Artificial Intelligence, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
| | - Junsuk Rho
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
- Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
- POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics, Pohang, Republic of Korea
- National Institute of Nanomaterials Technology (NINT), Pohang, Republic of Korea
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Latif S, Kim J, Khaliq HS, Mahmood N, Ansari MA, Chen X, Akbar J, Badloe T, Zubair M, Massoud Y, Mehmood MQ, Rho J. Spin-Selective Angular Dispersion Control in Dielectric Metasurfaces for Multichannel Meta-Holographic Displays. NANO LETTERS 2024; 24:708-714. [PMID: 38165767 DOI: 10.1021/acs.nanolett.3c04064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Angle-dependent next-generation displays have potential applications in 3D stereoscopic and head-mounted displays, image combiners, and encryption for augmented reality (AR) and security. Metasurfaces enable such exceptional functionalities with groundbreaking achievements in efficient displays over the past decades. However, limitations in angular dispersion control make them unfit for numerous nanophotonic applications. Here, we propose a spin-selective angle-dependent all-dielectric metasurface with a unique design strategy to manifest distinct phase information at different incident angles of light. As a proof of concept, the phase masks of two images are encoded into the metasurface and projected at the desired focal plane under different angles of left circularly polarized (LCP) light. Specifically, the proposed multifunctional metasurface generates two distinct holographic images under LCP illumination at angles of +35 and -35°. The presented holographic displays may provide a feasible route toward multifunctional meta-devices for potential AR displays, encrypted imaging, and information storage applications.
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Affiliation(s)
- Sabiha Latif
- MicroNano Lab, Department of Electrical Engineering, Information Technology University (ITU) of the Punjab, Ferozepur Road, Lahore 54600, Pakistan
| | - Joohoon Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Hafiz Saad Khaliq
- MicroNano Lab, Department of Electrical Engineering, Information Technology University (ITU) of the Punjab, Ferozepur Road, Lahore 54600, Pakistan
| | - Nasir Mahmood
- Innovative Technologies Laboratories (ITL), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Muhammad Afnan Ansari
- Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Xianzhong Chen
- Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Jehan Akbar
- Glasgow College, University of Electronic Science and Technology of China, Chengdu 610056, China
| | - Trevon Badloe
- Graduate School of Artificial Intelligence, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Muhammad Zubair
- Innovative Technologies Laboratories (ITL), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Yehia Massoud
- Innovative Technologies Laboratories (ITL), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Muhammad Qasim Mehmood
- MicroNano Lab, Department of Electrical Engineering, Information Technology University (ITU) of the Punjab, Ferozepur Road, Lahore 54600, Pakistan
| | - Junsuk Rho
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
- POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics, Pohang 37673, Republic of Korea
- National Institute of Nanomaterials Technology (NINT), Pohang 37673, Republic of Korea
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Huang PS, Chu CH, Huang SH, Su HP, Tanaka T, Wu PC. Varifocal Metalenses: Harnessing Polarization-Dependent Superposition for Continuous Focal Length Control. NANO LETTERS 2023; 23:10432-10440. [PMID: 37956251 DOI: 10.1021/acs.nanolett.3c03056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Traditional varifocal lenses are bulky and mechanically complex. Emerging active metalenses promise compactness and design flexibility but face issues like mechanical tuning reliability and nonlinear focal length tuning due to additional medium requirements. In this work, we propose a varifocal metalens design based on superimposing light intensity distributions from two orthogonal polarization states. This approach enables continuous and precise focal length control within the visible spectrum, while maintaining relatively high focusing efficiencies (∼41% in simulation and ∼28% in measurement) and quality. In experimental validation, the metalens exhibited flexible tunability, with the focal length continuously adjustable between two spatial positions upon variation of the incident polarization angle. The MTF results showed high contrast reproduction and sharp imaging, with a Strehl ratio of >0.7 for all polarization angles. With compactness, design flexibility, and high focusing quality, the proposed varifocal metalens holds potential for diverse applications, advancing adaptive and versatile optical devices.
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Affiliation(s)
- Po-Sheng Huang
- Department of Photonics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Cheng Hung Chu
- YongLin Institute of Health, National Taiwan University, Taipei 10672, Taiwan
| | - Shih-Hsiu Huang
- Department of Photonics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Hsiu-Ping Su
- Department of Photonics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Takuo Tanaka
- Innovative Photon Manipulation Research Team, RIKEN Center for Advanced Photonics, Saitama 351-0198, Japan
- Metamaterials Laboratory, RIKEN Cluster for Pioneering Research, Saitama 351-0198, Japan
- Institute of Post-LED Photonics, Tokushima University, 2-1 Minamijosanjima-cho, Tokushima, Tokushima 770-8506, Japan
| | - Pin Chieh Wu
- Department of Photonics, National Cheng Kung University, Tainan 70101, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan 70101, Taiwan
- Meta-nanoPhotonics Center, National Cheng Kung University, Tainan 70101, Taiwan
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