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Sayed SI, Mahmoud KR, Mubarak RI. Design and optimization of broadband metamaterial absorber based on manganese for visible applications. Sci Rep 2023; 13:11937. [PMID: 37488131 PMCID: PMC10366329 DOI: 10.1038/s41598-023-38263-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/05/2023] [Indexed: 07/26/2023] Open
Abstract
Metamaterial absorbers have been extensively researched due to their potential applications in photonics. This paper presents a highly efficient Broadband Metamaterial Absorber (BMA) based on a Manganese-Silica-Manganese three layer structure with a shaped pattern at the top layer. For maximum absorption efficiency, the geometrical parameters of the proposed absorber have been optimized based on Particle Swarm Optimization (PSO). The optimal structure with a thickness of 190 nm, can achieve more than 94% absorption spanning visible band (400-800) nm with 98.72% average absorption, and more than 90% absorption over the range from 365 to 888 nm. In the range from 447 to 717 nm, the design presented above 99% absorptivity, providing an ultra-wide bandwidth of 270 nm. The physical mechanism of absorption is illustrated through the exploration of the electric and magnetic field distributions. Additionally, the proposed structure maintains 85% absorption stability for wide incident angles up to 70° for both the TE and TM polarizations under oblique incidence. Further, the optimized absorber structure with excellent absorption capabilities makes it suitable for various applications, including optical sensors, thermal emitters, and color imaging applications.
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Affiliation(s)
- Shimaa I Sayed
- Electronics and Communications Department, Faculty of Engineering, Helwan University, Cairo, Egypt.
| | - K R Mahmoud
- Electronics and Communications Department, Faculty of Engineering, Helwan University, Cairo, Egypt
- National Telecommunications Regulatory Authority (NTRA), Giza, Egypt
| | - Roaa I Mubarak
- Electronics and Communications Department, Faculty of Engineering, Helwan University, Cairo, Egypt
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2
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Guo TL, Li F, Roussey M. Dielectric Cavity-Insulator-Metal (DCIM) Metamaterial Absorber in Visible Range. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1401. [PMID: 37110987 PMCID: PMC10145544 DOI: 10.3390/nano13081401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/11/2023] [Accepted: 04/15/2023] [Indexed: 06/19/2023]
Abstract
For many years, metamaterial absorbers have received much attention in a wide range of application fields. There is an increasing need to search for new design approaches that fulfill more and more complex tasks. According to the specific application requirements, design strategy can vary from structure configurations to material selections. A new combination of a dielectric cavity array, dielectric spacer, and gold reflector as a metamaterial absorber is proposed and theoretically studied in this work. The complexity of the dielectric cavities leads to a more flexible optical response than traditional metamaterial absorbers. It gives a new dimension of freedom for a real three-dimensional metamaterial absorber design.
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Affiliation(s)
- Tian-Long Guo
- Center for Photonics Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
- Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 1219 Zhongguan West Road, Ningbo 315201, China
| | - Fangfang Li
- Center for Photonics Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
| | - Matthieu Roussey
- Center for Photonics Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland
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3
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Go M, Lee D, Kim S, Jang J, Kim KW, Lee J, Shim S, Kim JK, Rho J. Facile Fabrication of Titanium Nitride Nanoring Broad-Band Absorbers in the Visible to Near-Infrared by Shadow Sphere Lithography. ACS APPLIED MATERIALS & INTERFACES 2023; 15:3266-3273. [PMID: 36598796 DOI: 10.1021/acsami.2c17875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Plasmonic broad-band absorbers have received much attention because of their high absorption and potential applications for light-absorbing devices such as thermophotovoltaics, solar energy harvesting, and thermal emitters. However, the fabrication of complex structures in a large area and thermostability remains a great challenge. Here, we report a titanium nitride nanoring broad-band absorber that has over 95% average absorption in the visible and near-infrared regions (400-900 nm). Nanoring structures in a large area (inch2) are fabricated by shadow sphere lithography, which can innovatively increase fabrication efficiency. The nanoring absorber showed over 2.3 times higher-temperature increases than flat film under the irradiation of light. These large-scale and broad-band absorbers have potential applications for solar energy conversion devices such as thermophotovoltaics and photothermal devices.
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Affiliation(s)
- Myeongcheol Go
- National Creative Research Initiative Center for Hybrid Nano Materials by High-Level Architectural Design of Block Copolymer, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
| | - Dasol Lee
- Department of Biomedical Engineering, Yonsei University, Wonju26493, Republic of Korea
| | - Sanghoon Kim
- National Creative Research Initiative Center for Hybrid Nano Materials by High-Level Architectural Design of Block Copolymer, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
| | - Junho Jang
- National Creative Research Initiative Center for Hybrid Nano Materials by High-Level Architectural Design of Block Copolymer, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
| | - Keon-Woo Kim
- National Creative Research Initiative Center for Hybrid Nano Materials by High-Level Architectural Design of Block Copolymer, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
| | - Jaeyong Lee
- National Creative Research Initiative Center for Hybrid Nano Materials by High-Level Architectural Design of Block Copolymer, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
| | - Sangmin Shim
- Department of Biomedical Engineering, Yonsei University, Wonju26493, Republic of Korea
| | - Jin Kon Kim
- National Creative Research Initiative Center for Hybrid Nano Materials by High-Level Architectural Design of Block Copolymer, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
- National Institute of Nanomaterials Technology (NINT), Pohang37673, Republic of Korea
| | - Junsuk Rho
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang37673, Republic of Korea
- POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics, Pohang37673, Republic of Korea
- National Institute of Nanomaterials Technology (NINT), Pohang37673, Republic of Korea
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4
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Zhang H, Wu H, Li X, Hao J, Li Q, Guan Z, Xu H, Liu C. Super broadband mid-infrared absorbers with ultrathin folded highly-lossy films. J Colloid Interface Sci 2023; 629:254-262. [PMID: 36155920 DOI: 10.1016/j.jcis.2022.09.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/12/2022] [Accepted: 09/07/2022] [Indexed: 11/15/2022]
Abstract
Super broadband optical absorbers with ultrathin films have been keenly pursued for a long time. Although highly lossy materials with sharp light attenuation have the potential to become super absorbers, a large percent of light from free space is inevitably reflected back for the distinct impedance mismatch. Here, a simple strategy, of which reducing the thickness of highly-lossy thin films to minish reflectance and simultaneously folding the ultrathin films to make light multiple pass through, is proposed to obtain super broadband mid-infrared absorbers with ultrathin films. Along this line, the absorbers were prepared by depositing Al-doped ZnO film on scaffolds consisted of alumina spherical shells, whose substrates were opaque. When the thickness of Al-doped ZnO is 43 nm and the layer number of scaffolds is three, a maximum average absorptance was achieved as 97.6% over the wavelength range from 3 to 15 μm. Applying this strategy on polished Al foil, excellent infrared camouflage performance on human-body background was demonstrated. Featured by the strong broadband optical absorption with ultrathin films, flexible access to multiple substrates and low-cost procedures, this approach has the potential in widespread applications of infrared thermal emitters and optoelectronic devices.
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Affiliation(s)
- Heng Zhang
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Hao Wu
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China.
| | - Xiaowen Li
- Department of Physics, Shanghai Normal University, Shanghai 200234, China
| | - Jiaming Hao
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Qunqing Li
- Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Zhiqiang Guan
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Hongxing Xu
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Chang Liu
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, and School of Physics and Technology, Wuhan University, Wuhan 430072, China.
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5
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Noureen S, Mehmood MQ, Ali M, Rehman B, Zubair M, Massoud Y. A unique physics-inspired deep-learning-based platform introducing a generalized tool for rapid optical-response prediction and parametric-optimization for all-dielectric metasurfaces. NANOSCALE 2022; 14:16436-16449. [PMID: 36326120 DOI: 10.1039/d2nr03644d] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Metasurfaces are composed of a two-dimensional array of carefully engineered subwavelength structures. They provide a novel compact alternative to conventional voluminous optical components. However, their design involves a time-consuming hit and trial procedure, requiring many iterative electromagnetic simulations through expensive commercial solvers. To overcome this non-practical design strategy, recently, various deep-learning-based fast and low computational cost networks have been proposed to design and optimize individual meta-atoms and complete metasurfaces. Most of them focus on optimizing the amplitude response of nanostructures, whereas mapping the phase response is a much more challenging problem that needs to be addressed. Since the metaatom's optical response is entirely reliant on and vulnerable to its geometrical structure, underlying material, and operating wavelength, changing any of these parameters changes the entire physics of the problem in hand. Here, we propose novel deep-learning-based generalized forward and inverse design approaches to optimize all-dielectric transmissive metasurfaces. The proposed forward predicting neural networks take all the geometrical parameters and the physical properties of the bar-shaped dielectric nano-resonators as the input and predict the cross-polarized transmission amplitude and modulated phase at eight distinct rotation angles of the nano-bar. These networks are generalized to predict the electromagnetic (EM) response of different dielectric materials at different operating wavelengths. An inverse design neural network is also proposed that takes the target transmission amplitude and phase at eight discrete orientation angles of the nano-bar as the primary input. The underlying physics of the problem is also incorporated by feeding the intrinsic material properties and the operating wavelength of the nano-bar as a second input to the inverse neural network. It predicts the optimum set of geometrical parameters to achieve maximum cross-polarized transmission and complete Pancharatnam-Berry (PB) phase coverage from 0 to 2π. The average test data mean square error (MSE) achieved for the forward predicting neural network is 1.8 × 10-3 and that of the inverse design neural network is 2.8 × 10-1. The average MSEs for different material's test samples are demonstrated to validate the generalizability of the proposed models in terms of seen and unseen materials. A comparative analysis of the proposed approach with conventional EM software optimization tools is performed to prove that the proposed inverse design works much faster than the conventional methods, also it can handle a comparatively larger range of parameters and predicts the results in a single run with high accuracy.
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Affiliation(s)
- Sadia Noureen
- MicroNano Lab, Electrical Engineering Department, Information Technology University (ITU) of the Punjab, Ferozepur Road, Lahore 54600, Pakistan.
| | - Muhammad Qasim Mehmood
- MicroNano Lab, Electrical Engineering Department, Information Technology University (ITU) of the Punjab, Ferozepur Road, Lahore 54600, Pakistan.
| | - Mohsen Ali
- Department of Computer Science, Information Technology University (ITU) of the Punjab, Arfa Software Technology Park, Ferozepur Road, Lahore 54600, Pakistan
| | | | - Muhammad Zubair
- MicroNano Lab, Electrical Engineering Department, Information Technology University (ITU) of the Punjab, Ferozepur Road, Lahore 54600, Pakistan.
| | - Yehia Massoud
- Innovative Technologies Laboratories (ITL), King Abdullah University of Science and Technology (KAUST), Saudi Arabia.
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6
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Raza HMT, Rana AS. Metamaterial Absorber for Solar Thermophotovoltaic Systems. 2022 THIRD INTERNATIONAL CONFERENCE ON LATEST TRENDS IN ELECTRICAL ENGINEERING AND COMPUTING TECHNOLOGIES (INTELLECT) 2022. [DOI: 10.1109/intellect55495.2022.9969393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Affiliation(s)
| | - Ahsan Sarwar Rana
- Air University,Department of electrical and computer engineering,Islamabad,Pakistan
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7
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Zhu Y, Hou G, Wang Q, Zhu T, Sun T, Xu J, Chen K. Silicon-based spectrally selective emitters with good high-temperature stability on stepped metasurfaces. NANOSCALE 2022; 14:10816-10822. [PMID: 35822626 DOI: 10.1039/d2nr02299k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Solar thermophotovoltaic (STPV) systems have attracted increasing attention due to their great prospects for breaking the Shockley-Queisser limit. As a critical component of high-performance STPV systems, fabrication of a spectrally selective emitter with good stability at high temperature is one of the main research challenges. In this study, we developed a hybrid silicon-based metasurface emitter with spectral selectivity and high temperature stability using a simple fabrication process by introducing a controlled silicon nitride (SiNx) layer on a silicon stepped nanopillar substrate coated with molybdenum (Mo). Owing to the cooperative effect of cavity mode resonance and the interference effect of the SiNx dielectric layer, our proposed silicon-based metasurface emitter achieves a broadband optical absorption of ∼95% in the wavelength range of 220-2000 nm, while effectively suppressing the heat radiation to ∼19% in the long wavelength range (>5 μm). Moreover, polarization-independence and angle-insensitivity behaviors are demonstrated in the emitters. Additionally, due to the presence of a SiNx protection layer, this silicon-based metasurface emitter is experimentally proved to sustain its excellent spectral properties after ultra-high temperature treatments, including annealing at 1273 K under an Ar atmosphere for 6 h, even at 1073 K in air for 1 h, which makes it an alternative candidate for application in actual STPV systems.
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Affiliation(s)
- Yu Zhu
- National Laboratory of Solid State Microstructures/School of Electronics Science and Engineering/Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
| | - Guozhi Hou
- National Laboratory of Solid State Microstructures/School of Electronics Science and Engineering/Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
| | - Qingyuan Wang
- National Laboratory of Solid State Microstructures/School of Electronics Science and Engineering/Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
| | - Ting Zhu
- National Laboratory of Solid State Microstructures/School of Electronics Science and Engineering/Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
| | - Teng Sun
- National Laboratory of Solid State Microstructures/School of Electronics Science and Engineering/Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
| | - Jun Xu
- National Laboratory of Solid State Microstructures/School of Electronics Science and Engineering/Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
| | - Kunji Chen
- National Laboratory of Solid State Microstructures/School of Electronics Science and Engineering/Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
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Abbas MA, Kim J, Rana AS, Kim I, Rehman B, Ahmad Z, Massoud Y, Seong J, Badloe T, Park K, Mehmood MQ, Zubair M, Rho J. Nanostructured chromium-based broadband absorbers and emitters to realize thermally stable solar thermophotovoltaic systems. NANOSCALE 2022; 14:6425-6436. [PMID: 35416207 DOI: 10.1039/d1nr08400c] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The efficiency of traditional solar cells is constrained due to the Shockley-Queisser limit, to circumvent this theoretical limit, the concept of solar thermophotovoltaics (STPVs) has been introduced. The typical design of an STPV system consists of a wideband absorber with its front side facing the sun. The back of this absorber is physically attached to the back of a selective emitter facing a low-bandgap photovoltaic (PV) cell. We demonstrate an STPV system consisting of a wideband absorber and emitter pair achieving a high absorptance of solar radiation within the range of 400-1500 nm (covering the visible and infrared regions), whereas the emitter achieves an emittance of >95% at a wavelength of 2.3 μm. This wavelength corresponds to the bandgap energy of InGaAsSb (0.54 eV), which is the targeted PV cell technology for our STPV system design. The material used for both the absorber and the emitter is chromium due to its high melting temperature of 2200 K. An absorber and emitter pair is also fabricated and the measured results are in agreement with the simulated results. The design achieves an overall solar-to-electrical simulated efficiency of 21% at a moderate temperature of 1573 K with a solar concentration of 3000 suns. Furthermore, an efficiency of 15% can be achieved at a low temperature of 873 K with a solar concentration of 500 suns. The designs are also insensitive to polarization and show negligible degradation in solar absorptance and thermal emittance with a change in the angle of incidence.
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Affiliation(s)
- Muhammad Aamir Abbas
- MicroNano Lab, Electrical Engineering Department, 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.
| | - Ahsan Sarwar Rana
- MicroNano Lab, Electrical Engineering Department, Information Technology University (ITU) of the Punjab, Ferozepur Road, Lahore 54600, Pakistan.
- Department of Electrical & Computer Engineering, Air University, Islamabad, 44000, Pakistan
| | - Inki Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
- Department of Biophysics, Institute of Quantum Biophysics, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | | | - Zubair Ahmad
- Qatar University Young Scientists Center (QUYSC), Qatar University, Doha 2713, Qatar
| | - Yehia Massoud
- Innovative Technologies Laboratory (ITL), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Junhwa Seong
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
| | - Trevon Badloe
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
| | - Keunhan Park
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Muhammad Qasim Mehmood
- MicroNano Lab, Electrical Engineering Department, Information Technology University (ITU) of the Punjab, Ferozepur Road, Lahore 54600, Pakistan.
| | - Muhammad Zubair
- MicroNano Lab, Electrical Engineering Department, 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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Vafapour Z. Cost-Effective Bull's Eye Aperture-Style Multi-Band Metamaterial Absorber at Sub-THz Band: Design, Numerical Analysis, and Physical Interpretation. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22082892. [PMID: 35458876 PMCID: PMC9029594 DOI: 10.3390/s22082892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 05/03/2023]
Abstract
Theoretical and numerical studies were conducted on plasmonic interactions at a polarization-independent semiconductor-dielectric-semiconductor (SDS) sandwiched layer design and a brief review of the basic theory model was presented. The potential of bull's eye aperture (BEA) structures as device elements has been well recognized in multi-band structures. In addition, the sub-terahertz (THz) band (below 1 THz frequency regime) is utilized in communications and sensing applications, which are in high demand in modern technology. Therefore, we produced theoretical and numerical studies for a THz-absorbing-metasurface BEA-style design, with N-beam absorption peaks at a sub-THz band, using economical and commercially accessible materials, which have a low cost and an easy fabrication process. Furthermore, we applied the Drude model for the dielectric function of semiconductors due to its ability to describe both free-electron and bound systems simultaneously. Associated with metasurface research and applications, it is essential to facilitate metasurface designs to be of the utmost flexible properties with low cost. Through the aid of electromagnetic (EM) coupling using multiple semiconductor ring resonators (RRs), we could tune the number of absorption peaks between the 0.1 and 1.0 THz frequency regime. By increasing the number of semiconductor rings without altering all other parameters, we found a translation trend of the absorption frequencies. In addition, we validated our spectral response results using EM field distributions and surface currents. Here, we mainly discuss the source of the N-band THz absorber and the underlying physics of the multi-beam absorber designed structures. The proposed microstructure has ultra-high potentials to utilize in high-power THz sources and optical biomedical sensing and detection applications based on opto-electronics technology based on having multi-band absorption responses.
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Affiliation(s)
- Zohreh Vafapour
- Department of Electrical and Computer Engineering, Queen’s University, Kingston, ON K7L 3N6, Canada; or or
- Department of Physics, School of Natural Sciences, University of California Merced, Merced, CA 95343, USA
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10
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Polarization and angular insensitive bendable metamaterial absorber for UV to NIR range. Sci Rep 2022; 12:4857. [PMID: 35318387 PMCID: PMC8941150 DOI: 10.1038/s41598-022-08829-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 03/14/2022] [Indexed: 11/24/2022] Open
Abstract
Broadband absorbers are required for solar energy harvesting because they efficiently absorb the incident photon in the wide-ranging solar spectrum. To ensure high absorption of photons, metamaterial absorbers (MMAs) have been a growing area of interest in recent years. In this article, an MMA is proposed using a metal–insulator–metal (MIM) structure (Ni–SiO2–Ni) that shows a near-unity broadband absorption of wavelengths from 300 to 1600 nm, with a 95.77% average absorption and a peak absorption of 99.999% at 772.82 nm. The MMA is polarization insensitive as well as wide incident angle stable. Analysis of the effects of mechanical bending on the absorption of the proposed structure shows that absorption holds satisfactory values at different degrees of mechanical loading. The suggested MMA unit cell structure was computationally simulated using the Finite Integration Technique (FIT) and verified using the Finite Element Method (FEM). To analyze the feasibility of the proposed MMA as a solar cell, it is investigated with the universal AM 1.5 solar spectrum characteristics. Besides solar energy harvesting, the proposed MMA unit cell may be employed in a variety of diverse optical applications, including sensors, detectors, and imaging.
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11
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Wang X, Sang T, Li G, Mi Q, Pei Y, Wang Y. Ultrabroadband and ultrathin absorber based on an encapsulated T-shaped metasurface. OPTICS EXPRESS 2021; 29:31311-31323. [PMID: 34615226 DOI: 10.1364/oe.435371] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
Ultrabroadband absorbers are vital for applications such as solar energy harvesting and integrated optoelectronic devices. Herein, we design, fabricate and characterize a novel ultrabroadband and ultrathin absorber based on the encapsulated T-shaped metasurface (ETM). The ETM consists of a 20 nm Cr film and a Cr substrate sandwiched by the T-shaped polymethyl methacrylate (PMMA) arrays. The Cr film provides a robust absorptive surface with improved impedance matching, and ultrabroadband absorption can be achieved via the excitation of the localized surface plasmon (LSP) of this ultrathin film. The average absorption of simulated and experimental results of the ETM in the visible range of 400-800 nm for the TM (TE) polarization are 96.4% (96.3%) and 90.6% (89.4%), respectively. Three-dimensional (3D) power dissipation density distributions of the proposed structure have been investigated, which indicates that the synergistic absorption effect of different parts of the T-shaped ultrathin Cr film contributes to the major absorption enhancement. The absorption of the ETM is very robust to the changes of geometrical parameters and the symmetry of the structure, and it can be maintained almost the same even if T-shaped profiles are changed to L-shaped profiles. Moreover, the absorption performance of the ETM exhibits polarization-insensitive and wide-angle features, which has advantages for many potential applications.
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12
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Kim J, Rana AS, Kim Y, Kim I, Badloe T, Zubair M, Mehmood MQ, Rho J. Chiroptical Metasurfaces: Principles, Classification, and Applications. SENSORS (BASEL, SWITZERLAND) 2021; 21:4381. [PMID: 34206760 PMCID: PMC8271883 DOI: 10.3390/s21134381] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/21/2021] [Accepted: 06/23/2021] [Indexed: 02/07/2023]
Abstract
Chiral materials, which show different optical behaviors when illuminated by left or right circularly polarized light due to broken mirror symmetry, have greatly impacted the field of optical sensing over the past decade. To improve the sensitivity of chiral sensing platforms, enhancing the chiroptical response is necessary. Metasurfaces, which are two-dimensional metamaterials consisting of periodic subwavelength artificial structures, have recently attracted significant attention because of their ability to enhance the chiroptical response by manipulating amplitude, phase, and polarization of electromagnetic fields. Here, we reviewed the fundamentals of chiroptical metasurfaces as well as categorized types of chiroptical metasurfaces by their intrinsic or extrinsic chirality. Finally, we introduced applications of chiral metasurfaces such as multiplexing metaholograms, metalenses, and sensors.
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Affiliation(s)
- Joohoon Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673, Korea; (J.K.); (Y.K.); (I.K.); (T.B.)
| | - Ahsan Sarwar Rana
- NanoTech Lab, Department of Electrical Engineering, Information Technology University of the Punjab, Ferozepur Road, Lahore 54600, Pakistan; (A.S.R.); (M.Z.)
| | - Yeseul Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673, Korea; (J.K.); (Y.K.); (I.K.); (T.B.)
| | - Inki Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673, Korea; (J.K.); (Y.K.); (I.K.); (T.B.)
| | - Trevon Badloe
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673, Korea; (J.K.); (Y.K.); (I.K.); (T.B.)
| | - Muhammad Zubair
- NanoTech Lab, Department of Electrical Engineering, Information Technology University of the Punjab, Ferozepur Road, Lahore 54600, Pakistan; (A.S.R.); (M.Z.)
| | - Muhammad Qasim Mehmood
- NanoTech Lab, Department of Electrical Engineering, Information Technology University of the Punjab, Ferozepur Road, Lahore 54600, Pakistan; (A.S.R.); (M.Z.)
| | - Junsuk Rho
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673, Korea; (J.K.); (Y.K.); (I.K.); (T.B.)
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang 37673, Korea
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13
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Oh DK, Lee T, Ko B, Badloe T, Ok JG, Rho J. Nanoimprint lithography for high-throughput fabrication of metasurfaces. FRONTIERS OF OPTOELECTRONICS 2021; 14:229-251. [PMID: 36637666 PMCID: PMC9743954 DOI: 10.1007/s12200-021-1121-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/02/2021] [Indexed: 05/27/2023]
Abstract
Metasurfaces are composed of periodic sub-wavelength nanostructures and exhibit optical properties that are not found in nature. They have been widely investigated for optical applications such as holograms, wavefront shaping, and structural color printing, however, electron-beam lithography is not suitable to produce large-area metasurfaces because of the high fabrication cost and low productivity. Although alternative optical technologies, such as holographic lithography and plasmonic lithography, can overcome these drawbacks, such methods are still constrained by the optical diffraction limit. To break through this fundamental problem, mechanical nanopatterning processes have been actively studied in many fields, with nanoimprint lithography (NIL) coming to the forefront. Since NIL replicates the nanopattern of the mold regardless of the diffraction limit, NIL can achieve sufficiently high productivity and patterning resolution, giving rise to an explosive development in the fabrication of metasurfaces. In this review, we focus on various NIL technologies for the manufacturing of metasurfaces. First, we briefly describe conventional NIL and then present various NIL methods for the scalable fabrication of metasurfaces. We also discuss recent applications of NIL in the realization of metasurfaces. Finally, we conclude with an outlook on each method and suggest perspectives for future research on the high-throughput fabrication of active metasurfaces.
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Affiliation(s)
- Dong Kyo Oh
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Taejun Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Byoungsu Ko
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Trevon Badloe
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jong G Ok
- Department of Mechanical and Automotive Engineering, Seoul National University of Science and Technology (SEOULTECH), Seoul, 01811, 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.
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14
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Broadband Absorption Based on Thin Refractory Titanium Nitride Patterned Film Metasurface. NANOMATERIALS 2021; 11:nano11051092. [PMID: 33922461 PMCID: PMC8145760 DOI: 10.3390/nano11051092] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 04/21/2021] [Accepted: 04/21/2021] [Indexed: 12/02/2022]
Abstract
In this paper, a thin metasurface perfect absorber based on refractory titanium nitride (TiN) is proposed. The size parameter of the metasurface is investigated based on the finite difference time domain method and transfer matrix method. With only a 15-nm-thick TiN layer inside the silica/TiN/silica stacks standing on the TiN substrate, the near-perfect absorption throughout the visible regime is realized. The cross-talk between the upper and lower dielectric layers enables the broadening of the absorption peak. After patterning the thin film into a nanodisk array, the resonances from the nanodisk array emerge to broaden the high absorption bandwidth. As a result, the proposed metasurface achieves perfect absorption in the waveband from 400 to 2000 nm with an average absorption of 95% and polarization-insensitivity under the normal incidence. The proposed metasurface maintains average absorbance of 90% up to 50-degree oblique incidence for unpolarized light. Our work shows promising potential in the application of solar energy harvesting and other applications requiring refractory metasurfaces.
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15
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Lee D, Go M, Kim M, Jang J, Choi C, Kim JK, Rho J. Multiple-patterning colloidal lithography-implemented scalable manufacturing of heat-tolerant titanium nitride broadband absorbers in the visible to near-infrared. MICROSYSTEMS & NANOENGINEERING 2021; 7:14. [PMID: 34567729 PMCID: PMC8433139 DOI: 10.1038/s41378-020-00237-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/19/2020] [Accepted: 12/29/2020] [Indexed: 06/01/2023]
Abstract
Broadband perfect absorbers have been intensively researched for decades because of their near-perfect absorption optical property that can be applied to diverse applications. Unfortunately, achieving large-scale and heat-tolerant absorbers has been remained challenging work because of costly and time-consuming lithography methods and thermolability of materials, respectively. Here, we demonstrate a thermally robust titanium nitride broadband absorber with >95% absorption efficiency in the visible and near-infrared region (400-900 nm). A relatively large-scale (2.5 cm × 2.5 cm) absorber device is fabricated by using a fabrication technique of multiple-patterning colloidal lithography. The optical properties of the absorber are still maintained even after heating at the temperatures >600 ∘C. Such a large-scale, heat-tolerant, and broadband near-perfect absorber will provide further useful applications in solar thermophotovoltaics, stealth, and absorption controlling in high-temperature conditions.
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Affiliation(s)
- Dasol Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Myeongcheol Go
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Minkyung Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Junho Jang
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Chungryong Choi
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Jin Kon Kim
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
- National Institute of Nanomaterials Technology (NINT), 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
- National Institute of Nanomaterials Technology (NINT), Pohang, 37673 Republic of Korea
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16
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Iwanaga M. High-Sensitivity High-Throughput Detection of Nucleic Acid Targets on Metasurface Fluorescence Biosensors. BIOSENSORS-BASEL 2021; 11:bios11020033. [PMID: 33513845 PMCID: PMC7911868 DOI: 10.3390/bios11020033] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/20/2021] [Accepted: 01/25/2021] [Indexed: 12/24/2022]
Abstract
Worldwide infection disease due to SARS-CoV-2 is tremendously affecting our daily lives. High-throughput detection methods for nucleic acids are emergently desired. Here, we show high-sensitivity and high-throughput metasurface fluorescence biosensors that are applicable for nucleic acid targets. The all-dielectric metasurface biosensors comprise silicon-on-insulator nanorod array and have prominent electromagnetic resonances enhancing fluorescence emission. For proof-of-concept experiment on the metasurface biosensors, we have conducted fluorescence detection of single-strand oligoDNAs, which model the partial sequences of SARS-CoV-2 RNA indicated by national infection institutes, and succeeded in the high-throughput detection at low concentrations on the order of 100 amol/mL without any amplification technique. As a direct detection method, the metasurface fluorescence biosensors exhibit high performance.
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Affiliation(s)
- Masanobu Iwanaga
- Research Center for Functional Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
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17
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Yao Y, Zhou J, Liu Z, Liu X, Fu G, Liu G. Refractory materials and plasmonics based perfect absorbers. NANOTECHNOLOGY 2021; 32:132002. [PMID: 33302265 DOI: 10.1088/1361-6528/abd275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 12/10/2020] [Indexed: 06/12/2023]
Abstract
In the past decades, metamaterial light absorbers have attracted tremendous attention due to their impressive absorption efficiency and significant potential for multiple kinds of applications. However, the conventional noble metals based metamaterial and nanomaterial absorbers always suffer from the structural damage by the local high temperature resulting from the strong plasmonic photo-thermal effects. To address this challenge, intensive research has been conducted to develop the absorbers which can realize efficient light absorption and simultaneously keep the structural stability under high temperatures. In this review, we present detail discussion on the refractory materials which can provide robust thermal stability and high performance for light absorption. Moreover, promising theoretical designs and experimental demonstrations that possess excellent features are also reviewed, including broadband strong light absorption, high temperature durability, and even the easy-to-fabricate configuration. Some applications challenges and prospects of refractory materials based plasmonic perfect absorbers are also introduced and discussed.
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Affiliation(s)
- Yu Yao
- Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, Jiangxi, People's Republic of China
| | - Jin Zhou
- Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, Jiangxi, People's Republic of China
| | - Zhengqi Liu
- Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, Jiangxi, People's Republic of China
| | - Xiaoshan Liu
- Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, Jiangxi, People's Republic of China
| | - Guolan Fu
- Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, Jiangxi, People's Republic of China
| | - Guiqiang Liu
- Jiangxi Key Laboratory of Nanomaterials and Sensors, Jiangxi Key Laboratory of Photoelectronics and Telecommunication, College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, Jiangxi, People's Republic of China
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18
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Mahmood N, Mehmood MQ, Tahir FA. Diamond step-index nanowaveguide to structure light efficiently in near and deep ultraviolet regimes. Sci Rep 2020; 10:18502. [PMID: 33116273 PMCID: PMC7595241 DOI: 10.1038/s41598-020-75718-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 10/20/2020] [Indexed: 11/25/2022] Open
Abstract
Two-dimensional metamaterials, consisting of an array of ultrathin building blocks, offer a versatile and compact platform for tailoring the properties of the electromagnetic waves. Such flat metasurfaces provide a unique solution to circumvent the limitations imposed by their three-dimensional counterparts. Albeit several successful demonstrations of metasurfaces have been presented in the visible, infrared, and terahertz regimes, etc., there is hardly any demonstration for ultraviolet wavelengths due to the unavailability of the appropriate lossless materials. Here, we present diamond as an ultra-low loss material for the near and deep ultraviolet (UV) light and engineer diamond step-index nanowaveguides (DSINs) to achieve full control over the phase and amplitude of the incident wave. A comprehensive analytical solution of step-index nanowaveguides (supported by the numerical study) is provided to describe the underlying mechanism of such controlled wavefront shaping. Due to the ultra-low loss nature of diamond in near and deep UV regimes, our DSINs and metasurfaces designed (from them) exhibit a decent efficiency of ≈ 84% over the entire spectrum of interest. To verify this high efficiency and absolute control over wavefront, we have designed polarization-insensitive meta-holograms through optimized DSINs for operational wavelength λ = 250 nm.
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Affiliation(s)
- Nasir Mahmood
- Research Institute for Microwave and Millimeter-Wave Studies (RIMMS), National University of Sciences and Technology (NUST), Islamabad, 46000, Pakistan
| | - Muhammad Qasim Mehmood
- NanoTech Lab, Department of Electrical Engineering, Information Technology University (ITU) of the Punjab, Ferozepur Road, Lahore, 54600, Pakistan
| | - Farooq Ahmad Tahir
- Research Institute for Microwave and Millimeter-Wave Studies (RIMMS), National University of Sciences and Technology (NUST), Islamabad, 46000, Pakistan.
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19
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Rana AS, Kim I, Ansari MA, Anwar MS, Saleem M, Tauqeer T, Danner A, Zubair M, Mehmood MQ, Rho J. Planar Achiral Metasurfaces-Induced Anomalous Chiroptical Effect of Optical Spin Isolation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:48899-48909. [PMID: 32981321 DOI: 10.1021/acsami.0c10006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Planar chiral structures respond differently for oppositely handed incident light, and thus can produce extraordinary chiroptical effects such as circular conversion dichroism (CCD) and asymmetric transmission (AT). Such chiroptical effects are powerful tools to realize the fundamental principle of optical spin isolation, which leads to a plethora of applications such as optical conversion diodes, chiral imaging, and sensing. Here, we demonstrate the chiroptical effects of simultaneous CCD and AT through meticulously designed single-layered achiral nanofins. Our metamolecule consists of four achiral hydrogenated amorphous silicon (a-Si:H) nanofins that are carefully oriented and optimized to exhibit considerable CCD and AT. The device demonstrates a circular conversion dichroism of 55% and an asymmetric transmission of 58% at a wavelength of 633 nm. Right-hand circularly polarized light (RHCP) is completely absorbed, while left-hand circularly polarized light (LHCP) is transmitted with a polarization conversion, making it a perfect circular polarization wave isolator with negligible backscattering (due to low reflectance). This unique design and its underlying working mechanism are described comprehensively with three different techniques. These methods validate the proposed design and its methodology. For practical applications such as imaging, the proposed design realizes the Pancharatnam-Berry (PB) phase, achieving a 0-2π phase coverage for transmitted circular polarization. For the proof of concept, a metahologram is designed and demonstrated by employing the achieved full-phase control. The measured response of the fabricated metadevice not only validates the CCD and AT but also exhibits a simulated polarization conversion efficiency of up to 71% and measured efficiency up to 52%, comparable to state-of-the-art metahologram demonstrations.
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Affiliation(s)
- Ahsan Sarwar Rana
- NanoTech Lab, Department of Electrical Engineering, Information Technology University of the Punjab, Ferozepur Road, Lahore 54600, Pakistan
| | - Inki Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Muhammad Afnan Ansari
- NanoTech Lab, Department of Electrical Engineering, Information Technology University of the Punjab, Ferozepur Road, Lahore 54600, Pakistan
| | - Muhammad Sabieh Anwar
- Laboratory for Quantum Technologies, Department of Physics, Syed Babar Ali School of Science and Engineering (SBASSE), Lahore University of Management Sciences (LUMS), Opposite Sector U, DHA Lahore 54792, Pakistan
| | - Murtaza Saleem
- Laboratory for Quantum Technologies, Department of Physics, Syed Babar Ali School of Science and Engineering (SBASSE), Lahore University of Management Sciences (LUMS), Opposite Sector U, DHA Lahore 54792, Pakistan
| | - Tauseef Tauqeer
- NanoTech Lab, Department of Electrical Engineering, Information Technology University of the Punjab, Ferozepur Road, Lahore 54600, Pakistan
| | - Aaron Danner
- Department of Electrical and Computer Engineering, National University of Singapore, 117583 Singapore, Singapore
| | - Muhammad Zubair
- NanoTech Lab, Department of Electrical Engineering, Information Technology University of the Punjab, Ferozepur Road, Lahore 54600, Pakistan
| | - Muhammad Qasim Mehmood
- NanoTech Lab, Department of Electrical Engineering, Information Technology University 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
- National Institute of Nanomaterials Technology (NINT), Pohang 37673, Republic of Korea
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20
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Iwanaga M. Non-Empirical Large-Scale Search for Optical Metasurfaces. NANOMATERIALS 2020; 10:nano10091739. [PMID: 32887266 PMCID: PMC7559444 DOI: 10.3390/nano10091739] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 08/29/2020] [Accepted: 08/31/2020] [Indexed: 11/20/2022]
Abstract
Metasurfaces are artificially designed, on-top, thin structures on bulk substrates, realizing various functions in recent years. Most metasurfaces have been conceived of for attaining optical functions, based on elaborate human knowledge-based designs for complex structures. Here, we introduce a method for a non-empirical, large-scale structural search to find optical metasurfaces, which enable us to access intended functions without depending on human knowledge and experience. This method is different from the optimization and modification reported so far. To illustrate the outputs in the non-empirical search, we show unpredictable, optically high-performance, all-dielectric metasurfaces found in the machine search. As an extension of the finding of a higher order diffractive structure, we furthermore show a light-focusing metadevice, which is diffraction-limited and has the unique feature that the focal length is almost invariant even when the distance from the incident spot to the metadevice largely varies.
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Affiliation(s)
- Masanobu Iwanaga
- Research Center for Functional Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
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21
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Parsamyan H. Near-perfect broadband infrared metamaterial absorber utilizing nickel. APPLIED OPTICS 2020; 59:7504-7509. [PMID: 32902448 DOI: 10.1364/ao.398609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/21/2020] [Indexed: 06/11/2023]
Abstract
We propose a thin, compact, broadband, polarization and angle insensitive metamaterial absorber based on a tungsten reflector, a silicon spacer, and a top pattern composed of a double square-like ring resonator utilizing nickel (Ni). In such a structure, a high absorption (above 80%) bandwidth ∼4.8µm from 3.52 up to 8.32 µm corresponding to the relative bandwidth ∼81% can be achieved with deeply subwavelength unit cell dimensions. Here the physical origin of the broadband absorption is associated with low Q-factor dipole modes of the top pattern inner and outer sides functioning as rectangular nanoantennas. Owing to the structural symmetry, the absorber shows a good incidence angle tolerance in the relatively wide range for both transverse electric and transverse magnetic polarizations. The effective parameters of the Ni-based absorber were retrieved using the constitutive effective medium theory, and the absorption characteristics of the effective medium and metamaterial were compared.
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22
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Ultrabroadband Absorption Enhancement via Hybridization of Localized and Propagating Surface Plasmons. NANOMATERIALS 2020; 10:nano10091625. [PMID: 32825058 PMCID: PMC7558930 DOI: 10.3390/nano10091625] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/09/2020] [Accepted: 08/16/2020] [Indexed: 11/17/2022]
Abstract
Broadband metamaterial absorbers (MAs) are critical for applications of photonic and optoelectronic devices. Despite long-standing efforts on broadband MAs, it has been challenging to achieve ultrabroadband absorption with high absorptivity and omnidirectional characteristics within a comparatively simple and low-cost architecture. Here we design, fabricate, and characterize a novel compact Cr-based MA to achieve ultrabroadband absorption in the visible to near-infrared wavelength region. The Cr-based MA consists of Cr nanorods and Cr substrate sandwiched by three pairs of SiO2/Cr stacks. Both simulated and experimental results show that an average absorption over 93.7% can be achieved in the range of 400–1000 nm. Specifically, the ultrabroadband features result from the co-excitations of localized surface plasmon (LSP) and propagating surface plasmon (PSP) and their synergistic absorption effects, where absorption in the shorter and longer wavelengths are mainly contributed bythe LSP and PSP modes, respectively. The Cr-based MA is very robust to variations of the geometrical parameters, and angle-and polarization-insensitive absorption can be operated well over a large range of anglesunder both transverse magnetic(TM)- and transverse electric (TE)-polarized light illumination.
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23
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Sajedian I, Badloe T, Lee H, Rho J. Deep Q-network to produce polarization-independent perfect solar absorbers: a statistical report. NANO CONVERGENCE 2020; 7:26. [PMID: 32748091 PMCID: PMC7399723 DOI: 10.1186/s40580-020-00233-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/23/2020] [Indexed: 05/06/2023]
Abstract
Using reinforcement learning, a deep Q-network was used to design polarization-independent, perfect solar absorbers. The deep Q-network selected the geometrical properties and materials of a symmetric three-layer metamaterial made up of circular rods on top of two films. The combination of all the possible permutations gives around 500 billion possible designs. In around 30,000 steps, the deep Q-network was able to produce 1250 structures that have an integrated absorption of higher than 90% in the visible region, with a maximum of 97.6% and an integrated absorption of less than 10% in the 8-13 µm wavelength region, with a minimum of 1.37%. A statistical analysis of the distribution of materials and geometrical parameters that make up the solar absorbers is presented.
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Affiliation(s)
- Iman Sajedian
- Department of Materials Science and Engineering, Korea University, Seoul, 02842, Republic of Korea
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Trevon Badloe
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Heon Lee
- Department of Materials Science and Engineering, Korea University, Seoul, 02842, 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.
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24
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Lee T, Lee C, Oh DK, Badloe T, Ok JG, Rho J. Scalable and High-Throughput Top-Down Manufacturing of Optical Metasurfaces. SENSORS (BASEL, SWITZERLAND) 2020; 20:E4108. [PMID: 32718085 PMCID: PMC7435655 DOI: 10.3390/s20154108] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/18/2020] [Accepted: 07/19/2020] [Indexed: 11/18/2022]
Abstract
Metasurfaces have shown promising potential to miniaturize existing bulk optical components thanks to their extraordinary optical properties and ultra-thin, small, and lightweight footprints. However, the absence of proper manufacturing methods has been one of the main obstacles preventing the practical application of metasurfaces and commercialization. Although a variety of fabrication techniques have been used to produce optical metasurfaces, there are still no universal scalable and high-throughput manufacturing methods that meet the criteria for large-scale metasurfaces for device/product-level applications. The fundamentals and recent progress of the large area and high-throughput manufacturing methods are discussed with practical device applications. We systematically classify various top-down scalable patterning techniques for optical metasurfaces: firstly, optical and printing methods are categorized and then their conventional and unconventional (emerging/new) techniques are discussed in detail, respectively. In the end of each section, we also introduce the recent developments of metasurfaces realized by the corresponding fabrication methods.
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Affiliation(s)
- Taejun Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea; (T.L.); (C.L.); (D.K.O.); (T.B.)
| | - Chihun Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea; (T.L.); (C.L.); (D.K.O.); (T.B.)
| | - Dong Kyo Oh
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea; (T.L.); (C.L.); (D.K.O.); (T.B.)
- Department of Mechanical and Automotive Engineering, Seoul National University of Science and Technology, Seoul 01811, Korea;
| | - Trevon Badloe
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea; (T.L.); (C.L.); (D.K.O.); (T.B.)
| | - Jong G. Ok
- Department of Mechanical and Automotive Engineering, Seoul National University of Science and Technology, Seoul 01811, Korea;
| | - Junsuk Rho
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea; (T.L.); (C.L.); (D.K.O.); (T.B.)
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
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25
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Feng L, Huo P, Liang Y, Xu T. Photonic Metamaterial Absorbers: Morphology Engineering and Interdisciplinary Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1903787. [PMID: 31566259 DOI: 10.1002/adma.201903787] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 08/29/2019] [Indexed: 06/10/2023]
Abstract
Recent advances in nanofabrication technologies have spurred many breakthroughs in the field of photonic metamaterials that provide efficient ways of manipulating light-matter interaction at subwavelength scales. As one of the most important applications, photonic metamaterials can be used to implement novel optical absorbers. First the morphology engineering of various photonic metamaterial absorbers is discussed, which is highly associated with impendence matching conditions and resonance modes of the absorbers, thus directly determines their absorption efficiency, operational bandwidth, incident angle, and polarization dependence. Then, the recent achievements of various interdisciplinary applications based on photonic metamaterial absorbers, including structural color generation, ultrasensitive optical sensing, solar steam generation, and highly responsive photodetection, are reviewed. This report is expected to provide an overview and vision for the future development of photonic metamaterial absorbers and their applications in novel nanophotonic systems.
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Affiliation(s)
- Lei Feng
- National Laboratory of Solid-State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Pengcheng Huo
- National Laboratory of Solid-State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Yuzhang Liang
- National Laboratory of Solid-State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Ting Xu
- National Laboratory of Solid-State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
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26
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Moth-eye shaped on-demand broadband and switchable perfect absorbers based on vanadium dioxide. Sci Rep 2020; 10:4522. [PMID: 32161273 PMCID: PMC7066148 DOI: 10.1038/s41598-020-59729-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/29/2020] [Indexed: 11/08/2022] Open
Abstract
Two biomimetic, moth-eye structure, perfect absorbers in the visible and near infrared regions are introduced and investigated. The moth-eye structure is made up of vanadium oxide (VO2), which is a phase change material that changes from an insulator state to a metallic state at around 85 °C. The VO2 structure sits on top of a sapphire (Al2O3) dielectric spacer layer, above a gold (Au) back reflector. Two perfect absorbers are designed, one with perfect absorption over an ultra-broadband range between 400 and 1,600 nm, for both the insulating and metallic phases, while the second can switch between being a perfect absorber or not in the range 1,000 and 1,600 nm. The absorption profiles and electric and magnetic fields are examined and discussed to provide insight into how absorbers function in the four different situations.
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27
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Badloe T, Kim I, Rho J. Biomimetic ultra-broadband perfect absorbers optimised with reinforcement learning. Phys Chem Chem Phys 2020; 22:2337-2342. [PMID: 31932814 DOI: 10.1039/c9cp05621a] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
By learning the optimal policy with a double deep Q-learning network (DDQN), we design ultra-broadband, biomimetic, perfect absorbers with various materials, based the structure of a moth's eye. All absorbers achieve over 90% average absorption from 400 to 1600 nm. By training a DDQN with moth-eye structures made up of chromium, we transfer the learned knowledge to other, similar materials to quickly and efficiently find the optimal parameters from the ∼1 billion possible options. The knowledge learned from previous optimisations helps the network to find the best solution for a new material in fewer steps, dramatically increasing the efficiency of finding designs with ultra-broadband absorption.
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Affiliation(s)
- Trevon Badloe
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
| | - Inki 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. and Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
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28
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Li Z, Liu W, Tang C, Cheng H, Li Z, Zhang Y, Li J, Chen S, Tian J. A Bilayer Plasmonic Metasurface for Polarization‐Insensitive Bidirectional Perfect Absorption. ADVANCED THEORY AND SIMULATIONS 2020. [DOI: 10.1002/adts.201900216] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Zhancheng Li
- The Key Laboratory of Weak Light Nonlinear PhotonicsMinistry of EducationSchool of Physics and TEDA Institute of Applied PhysicsNankai University Tianjin 300071 China
| | - Wenwei Liu
- The Key Laboratory of Weak Light Nonlinear PhotonicsMinistry of EducationSchool of Physics and TEDA Institute of Applied PhysicsNankai University Tianjin 300071 China
| | - Chengchun Tang
- Quantum LaboratoryAlibaba Cloud Intelligence Business Group Alibaba Group Hangzhou 310000 China
| | - Hua Cheng
- The Key Laboratory of Weak Light Nonlinear PhotonicsMinistry of EducationSchool of Physics and TEDA Institute of Applied PhysicsNankai University Tianjin 300071 China
| | - Zhi Li
- The Key Laboratory of Weak Light Nonlinear PhotonicsMinistry of EducationSchool of Physics and TEDA Institute of Applied PhysicsNankai University Tianjin 300071 China
| | - Yuebian Zhang
- The Key Laboratory of Weak Light Nonlinear PhotonicsMinistry of EducationSchool of Physics and TEDA Institute of Applied PhysicsNankai University Tianjin 300071 China
| | - Junjie Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of PhysicsChinese Academy of Sciences Beijing 100190 China
| | - Shuqi Chen
- The Key Laboratory of Weak Light Nonlinear PhotonicsMinistry of EducationSchool of Physics and TEDA Institute of Applied PhysicsNankai University Tianjin 300071 China
- Renewable Energy Conversion and Storage CenterNankai University Tianjin 300071 China
- The Collaborative Innovation Center of Extreme OpticsShanxi University Taiyuan Shanxi 030006 China
- Collaborative Innovation Center of Light Manipulations and ApplicationsShandong Normal University Jinan 250358 China
| | - Jianguo Tian
- The Key Laboratory of Weak Light Nonlinear PhotonicsMinistry of EducationSchool of Physics and TEDA Institute of Applied PhysicsNankai University Tianjin 300071 China
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29
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Mahmood N, Jeong H, Kim I, Mehmood MQ, Zubair M, Akbar A, Saleem M, Anwar MS, Tahir FA, Rho J. Twisted non-diffracting beams through all dielectric meta-axicons. NANOSCALE 2019; 11:20571-20578. [PMID: 31637386 DOI: 10.1039/c9nr04888j] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We demonstrate transmission-based all-dielectric, highly efficient (≈73.4%) and polarization-insensitive meta-axicons (for the visible wavelength of 633 nm) to generate zero and higher order Bessel beams without using additional components. The Bessel beams, owing to their diverse applications and non-diffractive properties, attract great interest from the scientific community. It is shown that the propagation length can be increased through a lower numerical aperture (∼2600 λ for NA = 0.1) whereas a higher full width at half maximum (< 0.5 λ) can be obtained for a higher numerical aperture (for NA ≥ 0.7). Our dielectric material, hydrogenated amorphous silicon (a-Si:H), provides a significant efficiency advantage over plasmonic and other high-index all-dielectric (e.g., TiO2 and GaN) metasurfaces in terms of cost, ease of fabrication, and CMOS compatibility. The finite difference time domain (FDTD) technique based numerically simulated and experimental results show excellent agreement. Due to the technological and scientific importance of the Bessel beams, the recommended material and meta-axicons provide an efficient and compact platform for realizing various advanced applications like optical manipulation, optical alignment, laser fabrication, imaging, and laser machining.
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Affiliation(s)
- Nasir Mahmood
- Research Institute for Microwave and Millimeter-wave Studies (RIMMS), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan.
| | - Heonyeong Jeong
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
| | - Inki Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
| | - Muhammad Qasim Mehmood
- NanoTech Lab, Department of Electrical Engineering, Information Technology University of the Punjab, Ferozepur Road, Lahore 54600, Pakistan
| | - Muhammad Zubair
- NanoTech Lab, Department of Electrical Engineering, Information Technology University of the Punjab, Ferozepur Road, Lahore 54600, Pakistan
| | - Ali Akbar
- Laboratory for Quantum Technologies, Department of Physics, Syed Babar Ali School of Science and Engineering (SBASSE), Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A., Lahore 54792, Pakistan.
| | - Murtaza Saleem
- Laboratory for Quantum Technologies, Department of Physics, Syed Babar Ali School of Science and Engineering (SBASSE), Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A., Lahore 54792, Pakistan.
| | - Muhammad Sabieh Anwar
- Laboratory for Quantum Technologies, Department of Physics, Syed Babar Ali School of Science and Engineering (SBASSE), Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A., Lahore 54792, Pakistan.
| | - Farooq Ahmad Tahir
- Research Institute for Microwave and Millimeter-wave Studies (RIMMS), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan.
| | - Junsuk Rho
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea. and Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
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30
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Li C, Fan H, Dai Q, Wei Z, Lan S, Liu H. Multipole Resonance in Arrays of Diamond Dielectric: A Metamaterial Perfect Absorber in the Visible Regime. NANOMATERIALS 2019; 9:nano9091222. [PMID: 31470586 PMCID: PMC6780810 DOI: 10.3390/nano9091222] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 11/16/2022]
Abstract
Excellent characteristics and promising application prospects promote the rapid development of metamaterials. We have numerically proposed and demonstrated a novel subwavelength broadband metamaterial perfect absorber (BMPA) based on diamond dielectric arrays. The proposed absorber is composed of an ultra-thin two-layer structure covering the dielectric periodic array on a metal substrate. The materials of dielectric silicon (Si) and gold (Au) substrate are discussed in detail. In addition, different dielectric and refractory materials are also applied to achieve broadband absorption, which will make the proposed absorber greatly broaden the application field. A perfect absorption window (i.e., absorption rate exceeding 90%) can be obtained from near-ultraviolet to the visible range. The average absorption rate of 93.3% is achieved in the visible range. The results of multipole decomposition show that broadband absorption is mainly caused by electromagnetic dipole resonance and lattice resonance in a periodic array of Si. The proposed absorber can be extended freely by adjusting the structural parameters. The polarization-independent and incident angle insensitivity are proved. The proposed absorber may well be used in light energy acquisition, as well as for the scalability of optoelectronic and sensing devices.
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Affiliation(s)
- Chenhui Li
- Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China
| | - Haihua Fan
- Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China
| | - Qiaofeng Dai
- Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China
| | - Zhongchao Wei
- Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China
| | - Sheng Lan
- Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China
| | - Haiying Liu
- Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China.
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31
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Sajedian I, Lee H, Rho J. Double-deep Q-learning to increase the efficiency of metasurface holograms. Sci Rep 2019; 9:10899. [PMID: 31358783 PMCID: PMC6662763 DOI: 10.1038/s41598-019-47154-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 07/09/2019] [Indexed: 11/30/2022] Open
Abstract
We use a double deep Q-learning network (DDQN) to find the right material type and the optimal geometrical design for metasurface holograms to reach high efficiency. The DDQN acts like an intelligent sweep and could identify the optimal results in ~5.7 billion states after only 2169 steps. The optimal results were found between 23 different material types and various geometrical properties for a three-layer structure. The computed transmission efficiency was 32% for high-quality metasurface holograms; this is two times bigger than the previously reported results under the same conditions. The found structure is transmission-type and polarization-independent and works in the visible region.
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Affiliation(s)
- Iman Sajedian
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.,Department of Materials Science and Engineering, Korea University, Seoul, 02842, Republic of Korea
| | - Heon Lee
- Department of Materials Science and Engineering, Korea University, Seoul, 02842, 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.
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32
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Abstract
In the light of the ever increasing dangers of global warming, the efforts to reduce energy consumption by radiative cooling techniques have been designed, but are inefficient under strong sunlight during the daytime. With the advent of metamaterials and their selective control over optical properties, radiative cooling under direct sunlight is now possible. The key principles of metamaterial-based radiative cooling are: almost perfect reflection in the visible and near-infrared spectrum (0.3–3 µm) and high thermal emission in the infrared atmospheric window region (8–13 µm). Based on these two basic principles, studies have been conducted using various materials and structures to find the most efficient radiative cooling system. In this review, we analyze the materials and structures being used for radiative cooling, and suggest the future perspectives as a substitute in the current cooling industry.
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Recent Advances in Tunable and Reconfigurable Metamaterials. MICROMACHINES 2018; 9:mi9110560. [PMID: 30715059 PMCID: PMC6267285 DOI: 10.3390/mi9110560] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 10/26/2018] [Indexed: 12/17/2022]
Abstract
Metamaterials are composed of nanostructures, called artificial atoms, which can give metamaterials extraordinary properties that cannot be found in natural materials. The nanostructures themselves and their arrangements determine the metamaterials’ properties. However, a conventional metamaterial has fixed properties in general, which limit their use. Thus, real-world applications of metamaterials require the development of tunability. This paper reviews studies that realized tunable and reconfigurable metamaterials that are categorized by the mechanisms that cause the change: inducing temperature changes, illuminating light, inducing mechanical deformation, and applying electromagnetic fields. We then provide the advantages and disadvantages of each mechanism and explain the results or effects of tuning. We also introduce studies that overcome the disadvantages or strengthen the advantages of each classified tunable metamaterial.
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34
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All-Dielectric Metasurfaces with High-Fluorescence-Enhancing Capability. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8081328] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
All-dielectric metasurfaces are an emerging subfield in photonics. Light-wave manipulation has been extensively explored in these metasurfaces. Although light–matter interaction has also been investigated in these metasurfaces, only a limited number of studies have been reported to date. Here, we employ Si-rod-array metasurfaces to examine their fluorescence-enhancing capability. They were designed to have prominent resonances at the working wavelengths of fluorescent molecules. As a result, we experimentally observed significant fluorescence intensity enhancement, exceeding 1000-fold for a reference substrate that was a non-enhancing, flat Si wafer. Thus, we conclude that the all-dielectric metasurfaces can potentially serve as highly fluorescence-enhancing platforms. Their performance is comparable to the best performance reported for metallic metasurfaces. These results strongly suggest that all-dielectric metasurfaces can contribute to fluorescence-sensing of diverse molecules, including biomolecules.
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