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Khalid R, Wu QYS, Mahmood N, Deng J, Nemati A, Sreekanth KV, Cabrera H, Mehmood MQ, Teng J, Zubair M. Fluid-responsive tunable metasurfaces for high-fidelity optical wireless communication. MATERIALS HORIZONS 2024. [PMID: 38994895 DOI: 10.1039/d4mh00592a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
Optical wireless communication (OWC), with its blazing data transfer speed and unparalleled security, is a futuristic technology for wireless connectivity. Despite the significant advancements in OWC, the realization of tunable devices for on-demand and versatile connectivity still needs to be explored. This presents a considerable limitation in utilizing adaptive technologies to improve signal directivity and optimize data transfer. This study proposes a unique platform that utilizes tunable, fluid-responsive multifunctional metasurfaces offering dynamic and unprecedented control over electromagnetic wave manipulation to enhance the performance of OWC networks. We have achieved real-time, on-demand beam steering with vary-focusing capability by integrating the fabricated metasurfaces with different isotropic fluids. Furthermore, the designed metasurfaces are capable of polarization-based switching of the diffracted light beams to enhance overall productivity. Our research has showcased the potential of fluid-responsive tunable metasurfaces in revolutionizing OWC networks by significantly improving transmission reliability and signal quality through real-time adjustments. The proposed methodology is verified by designing and fabricating an all-dielectric metasurface measuring 500 μm × 500 μm and experimentally investigating its fluid-responsive vary-focal capability. By incorporating fluid-responsive properties into spin-decoupled metasurfaces, we aim to develop advanced high-tech optical devices and systems to simplify beam-steering and improve performance, adaptability, and functionality, making the devices suitable for various practical applications.
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Affiliation(s)
- Ramna Khalid
- MicroNano Lab, Department of Electrical Engineering, Information Technology University of the Punjab (ITU), 54000 Lahore, Pakistan.
| | - Qing Yang Steve Wu
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore.
| | - Nasir Mahmood
- MicroNano Lab, Department of Electrical Engineering, Information Technology University of the Punjab (ITU), 54000 Lahore, Pakistan.
| | - Jie Deng
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore.
| | - Arash Nemati
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore.
| | - Kandammathe Valiyaveedu Sreekanth
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore.
| | - Humberto Cabrera
- MLab, STI Unit, The Abdus Salam International Centre for Theoretical Physics, Trieste, 34151, Italy
| | - Muhammad Qasim Mehmood
- MicroNano Lab, Department of Electrical Engineering, Information Technology University of the Punjab (ITU), 54000 Lahore, Pakistan.
| | - Jinghua Teng
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore.
| | - Muhammad Zubair
- MicroNano Lab, Department of Electrical Engineering, Information Technology University of the Punjab (ITU), 54000 Lahore, Pakistan.
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Li H, Zhang B, Wang Y, Huang Z, Xu J, Ding J. Achieving focal invariance in different background refractive indices through a dual-environment metalens. APPLIED OPTICS 2024; 63:1600-1605. [PMID: 38437374 DOI: 10.1364/ao.511027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/28/2024] [Indexed: 03/06/2024]
Abstract
A conventional metalens is designed with a fixed working environment, and its focal length depends on the background refractive index. In this study, we propose a dual-environment metalens that can maintain the same focal length in both media of air and water. The metalens consists of 16 types of meta-atoms with different geometries, which can cover the 0-2π phase range in both air and water. We perform finite-difference time-domain simulations to investigate the metalens and demonstrate that its focal length remains unchanged, regardless of whether the background medium is air or water. Furthermore, we investigated the optical forces within the focal field of the metalens in both air and water, indicating its potential trapping capability in these media. Our method provides a new insight into dual-environment metasurfaces and advances the methodology of electromagnetic structures in extensive applications.
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Li JS, Cheng J, Zhang DP. Terahertz Bessel beam generator. APPLIED OPTICS 2023; 62:4197-4202. [PMID: 37706904 DOI: 10.1364/ao.488764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/09/2023] [Indexed: 09/15/2023]
Abstract
The Bessel beam has broad application prospects in wireless energy transmission and high-speed communications. The traditional Bessel beam generation method has the problems of large volume, low efficiency, and complex manufacturing. To solve the above problems, we present a terahertz Bessel beam generator based on the reflective metasurface, which is composed of a metal pattern, dielectric layer, and bottom metal plate. Under the incidence of right circularly polarized (RCP) wave, the zero-order Bessel beam and zero-order symmetric double Bessel beam are generated. It can be found that the bottom angle of the axicon of the first-order Bessel beam is inversely proportional to the propagation distance of the Bessel beam. Comparing the electric field intensity distribution, phase distribution, and mode purity of the second-order Bessel beam and the second-order vortex beam in different observation planes, it can be seen that the energy of the higher-order Bessel beam is more concentrated and the field distribution is more stable than those of the ordinary vortex beam. The reflective terahertz Bessel beam generator has potential application value in terahertz wireless communications, measurement, radar detection, and imaging.
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Yang Y, Zhu Y, Xie W, Bu L, Zang Y, Liu X. High-efficiency ultrathin metasurfaces with simultaneous control of complete phase, amplitude, and polarization. OPTICS EXPRESS 2023; 31:3134-3142. [PMID: 36785311 DOI: 10.1364/oe.470556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/11/2022] [Indexed: 06/18/2023]
Abstract
Metasurfaces that can simultaneously manipulate both amplitude and phase have garnered interest and have promising applications owing to their strong beam-steering ability; however, achieving a high maximum transmission while covering the full phase shift remains challenging. This paper proposes a chiral-structured meta-atom composed of two external cross-polarized patches and an internal coupling structure. It enables the independent modulation of the phase, amplitude, and polarization at large incidence angles and ensures a high maximum transmission with a complete phase shift enabled by the two internal rotation structures. The transmission phase and amplitude can be independently controlled by adjusting the geometry and rotation angle of the meta-atoms. The performance and feasibility of the method were verified using an ultra-thin high-order Bessel beam generator sample with a thickness of 2 mm (about λ0/11 at 14 GHz). This design can meet arbitrary requirements for extreme beam steering and has broad application prospects in the fields of electromagnetism and photonics.
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Shang G, Guan C, Zhang K, Wu Q, Liu J, Ding X, Li H, Burokur SN, Ding X. Design of a frequency-multiplexed metasurface with asymmetric transmission. OPTICS LETTERS 2022; 47:4504-4507. [PMID: 36048690 DOI: 10.1364/ol.464854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
Metasurfaces presenting diversified functionalities have broadened the prospect of manipulating the phase, amplitude, and polarization from the optical to microwave fields. Although the frequency-multiplexing strategy is one of the intuitive and effective approaches to expand the number of channels, demonstrations reporting on the combination between directional asymmetric transmission and frequency-multiplexing via an ultrathin flat device are limited. In this study, a novel, to the best of our knowledge, strategy is proposed to generate four independent holographic images under opposite illumination directions at two operating frequencies, utilizing a single metasurface composed of two types of metallic resonators and one grating layer. Specifically, each scattering channel with independent information makes full use of the whole metasurface. Simulation and experimental results show good agreement, highlighting the attractive capabilities of the multi-functional metasurface platform, which provides more freedom for the manipulation of electromagnetic waves.
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Li JS, Chen Y. Terahertz device utilizing a transmissive geometric metasurface. APPLIED OPTICS 2022; 61:4140-4144. [PMID: 36256090 DOI: 10.1364/ao.452723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/20/2022] [Indexed: 06/16/2023]
Abstract
Due to potential applications in next generation high-capacity wireless communication systems, generating and controlling vortex beams carrying orbital angular momentum (OAM) has received considerable attention. In this work, a scheme is proposed to generate two/four splitting vortex beams and focusing vortex beams with different topological charges under left circularly polarized and right circularly polarized terahertz waves under incidence. The meta-unit cell consists of a two-flying-fish-shaped patterned metallic top layer and an identical metallic patterned bottom layer separated by a silica layer. Full-wave simulation results agree well with that of calculation predictions. The proposed terahertz metasurface-based devices are able to carry different OAM modes and can abruptly manipulate during propagation, which indicates that such metasurface-based devices may have promising applications in terahertz wireless communication links in the future.
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Zhang Y, Li Z, Qin S, Huang H, Jie K, Guo J, Liu H, Meng H, Wang F, Yang X, Wei Z. Band-tunable achromatic metalens based on phase change material. OPTICS EXPRESS 2022; 30:17541-17553. [PMID: 36221574 DOI: 10.1364/oe.456752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/29/2022] [Indexed: 06/16/2023]
Abstract
Achromatic metalens have the potential to significantly reduce the size and complexity of broadband imaging systems. A large variety of achromatic metalens has been proposed and most of them have the fixed achromatic band that cannot be actively modified. However, band-tunable is an important function in practical applications such as fluorescence microscopic imaging and optical detection. Here, we propose a bilayer metalens that can switch achromatic bands by taking the advantage of the high refractive index contrast of Sb2S3 between amorphous and crystalline state. By switching the state of Sb2S3, the achromatic band can be reversibly switched between the red region of visible spectrum (650-830 nm) and the near-infrared spectrum (830-1100 nm). This band-tunable design indicates a novel (to our knowledge) method to solve the problem of achromatic focusing in an ultrabroad band. The metalens have an average focusing efficiency of over 35% and 55% in two bands while maintaining diffraction-limited performance. Moreover, through proper design, we can combine different functionalities in two bands such as combining achromatic focusing and diffractive focusing. The proposed metalens have numerous potential applications in tunable displaying, detecting devices and multifunctional devices.
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Liu C, Li Y, Feng X, Zhang X, Han J, Zhang W. Dual non-diffractive terahertz beam generators based on all-dielectric metasurface. FRONTIERS OF OPTOELECTRONICS 2021; 14:201-210. [PMID: 36637662 PMCID: PMC9743854 DOI: 10.1007/s12200-020-1098-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 11/01/2020] [Indexed: 05/09/2023]
Abstract
The applications of terahertz (THz) technology can be greatly extended using non-diffractive beams with unique field distributions and non-diffractive transmission characteristics. Here, we design and experimentally demonstrate a set of dual non-diffractive THz beam generators based on an all-dielectric metasurface. Two kinds of non-diffractive beams with dramatically opposite focusing properties, Bessel beam and abruptly autofocusing (AAF) beam, are considered. A Bessel beam with long-distance non-diffractive characteristics and an AAF beam with low energy during transmission and abruptly increased energy near the focus are generated for x- and y-polarized incident waves, respectively. These two kinds of beams are characterized and the results agree well with simulations. In addition, we show numerically that these two kinds of beams can also carry orbital angular momentum by further imposing proper angular phases in the design. We believe that these metasurface-based beam generators have great potential use in THz imaging, communications, non-destructive evaluation, and many other fields.
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Affiliation(s)
- Chunyu Liu
- Center for Terahertz Waves, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronics Information and Technology (Ministry of Education of China), Tianjin University, Tianjin, 300072, China
| | - Yanfeng Li
- Center for Terahertz Waves, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronics Information and Technology (Ministry of Education of China), Tianjin University, Tianjin, 300072, China.
| | - Xi Feng
- Center for Terahertz Waves, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronics Information and Technology (Ministry of Education of China), Tianjin University, Tianjin, 300072, China
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Xixiang Zhang
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Jiaguang Han
- Center for Terahertz Waves, College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronics Information and Technology (Ministry of Education of China), Tianjin University, Tianjin, 300072, China
| | - Weili Zhang
- School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, OK, 74078, USA
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Chen L, Hao Y, Zhao L, Wu R, Liu Y, Wei Z, Xu N, Li Z, Liu H. Multifunctional metalens generation using bilayer all-dielectric metasurfaces. OPTICS EXPRESS 2021; 29:9332-9345. [PMID: 33820364 DOI: 10.1364/oe.420003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
Optical metasurfaces exhibit unprecedented ability in light field control due to their ability to locally change the phase, amplitude, and polarization of transmitted or reflected light. We propose a multifunctional metalens with dual working modes based on bilayer geometric phase elements consisting of low-loss phase change materials (Sb2Se3) and amorphous silicon (a-Si). In transmission mode, by changing the crystalline state of the Sb2Se3 scatterer, a bifocal metalens with an arbitrary intensity ratio at the telecommunication C-band is realized, and the total focusing efficiency of the bifocal metalens is as high as 78%. Also, at the resonance wavelength of the amorphous Sb2Se3 scatterer, the scatterer can be regarded as a half-wave plate in reflection mode. The multifunctional metalens can reversely converge incident light into a focal point with a focusing efficiency of up to 30%. The high focusing efficiency, dynamic reconfigurability, and dual working modes of the multifunctional metalens contribute to polarization state detection, optical imaging, and optical data storage. In addition, the bilayer geometric phase elements can be easily extended to multilayer, which significantly improves the capability of manipulating the incident light field.
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Khaliq HS, Akram MR, Riaz K, Ansari MA, Akbar J, Zhang J, Zhu W, Zhang D, Wang X, Zubair M, Mehmood MQ. Single-layered meta-reflectarray for polarization retention and spin-encrypted phase-encoding. OPTICS EXPRESS 2021; 29:3230-3242. [PMID: 33770926 DOI: 10.1364/oe.415562] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/05/2021] [Indexed: 06/12/2023]
Abstract
Broadband communication with high data rates is a dire need for state-of-the-art wireless technologies. For achieving efficient wireless communication (particularly in an indoor environment), the electromagnetic (EM) waves should maintain their state of polarization despite encountering multiple reflections. Metasurfaces provide a unique platform to design subwavelength-featured meta-reflectarrays which enable the desired retention of the polarization state of an EM wave upon reflection. We present a single-layered broadband meta-reflectarray, simultaneously breaking n-fold (n > 2) rotational and mirror symmetry, which exhibits an unprecedented control over the phase, amplitude, and polarization of a reflected EM wave. This unique control enables the retention of polarization state and recording of spin-encrypted information for the reflected EM waves. Such novel multifunctional meta-reflectarray can be crucial to building an indoor setup for high data rate wireless communications. Meanwhile, the meta-array's ability to encode phase information provides an extra degree of freedom to structure and control (via incident spin) the reflected EM beam in the desired way. For the proof of concept, we have experimentally demonstrated a spin-encrypted holographic display which reconstructs the recorded holographic image at an image plane for the left circularly polarized (LCP) illumination and exhibits circular dichroism for the right circularly polarized (RCP) incident waves. The proposed meta-array can find applications in 5G indoor wireless communication, chiral sensing, spin-selective imaging, holography, and encryption.
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11
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Zeroth- and first-order long range non-diffracting Gauss-Bessel beams generated by annihilating multiple-charged optical vortices. Sci Rep 2020; 10:21981. [PMID: 33319796 PMCID: PMC7738530 DOI: 10.1038/s41598-020-78613-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/18/2020] [Indexed: 11/15/2022] Open
Abstract
We demonstrate an alternative approach for generating zeroth- and first-order long range non-diffracting Gauss–Bessel beams (GBBs). Starting from a Gaussian beam, the key point is the creation of a bright ring-shaped beam with a large radius-to-width ratio, which is subsequently Fourier-transformed by a thin lens. The phase profile required for creating zeroth-order GBBs is flat and helical for first-order GBBs with unit topological charge (TC). Both the ring-shaped beam and the required phase profile can be realized by creating highly charged optical vortices by a spatial light modulator and annihilating them by using a second modulator of the same type. The generated long-range GBBs are proven to have negligible transverse evolution up to 2 m and can be regarded as non-diffracting. The influences of the charge state of the TCs, the propagation distance behind the focusing lens, and the GBB profiles on the relative intensities of the peak/rings are discussed. The method is much more efficient as compared to this using annular slits in the back focal plane of lenses. Moreover, at large propagation distances the quality of the generated GBBs significantly surpasses this of GBBs created by low angle axicons. The developed analytical model reproduces the experimental data. The presented method is flexible, easily realizable by using a spatial light modulator, does not require any special optical elements and, thus, is accessible in many laboratories.
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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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Yuan Y, Sun S, Chen Y, Zhang K, Ding X, Ratni B, Wu Q, Burokur SN, Qiu C. A Fully Phase-Modulated Metasurface as An Energy-Controllable Circular Polarization Router. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2001437. [PMID: 32999848 PMCID: PMC7509705 DOI: 10.1002/advs.202001437] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/14/2020] [Indexed: 05/22/2023]
Abstract
Geometric metasurfaces primarily follow the physical mechanism of Pancharatnam-Berry (PB) phases, empowering wavefront control of cross-polarized reflective/transmissive light components. However, inherently accompanying the cross-polarized components, the copolarized output components have not been attempted in parallel in existing works. Here, a general method is proposed to construct phase-modulated metasurfaces for implementing functionalities separately in co- and cross-polarized output fields under circularly polarized (CP) incidence, which is impossible to achieve with solely a geometric phase. By introducing a propagation phase as an additional degree of freedom, the electromagnetic (EM) energy carried by co- and cross-polarized transmitted fields can be fully phase-modulated with independent wavefronts. Under one CP incidence, a metasurface for separate functionalities with controllable energy repartition is verified by simulations and proof-of-principle microwave experiments. A variety of applications can be readily expected in spin-selective optics, spin-Hall metasurfaces, and multitasked metasurfaces operating in both reflective and transmissive modes.
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Affiliation(s)
- Yueyi Yuan
- Department of Microwave EngineeringHarbin Institute of TechnologyHarbin150001China
| | - Shang Sun
- Department of Electrical and Computer EngineeringNational University of SingaporeSingapore117583Singapore
| | - Yang Chen
- Department of Electrical and Computer EngineeringNational University of SingaporeSingapore117583Singapore
| | - Kuang Zhang
- Department of Microwave EngineeringHarbin Institute of TechnologyHarbin150001China
| | - Xumin Ding
- Department of Microwave EngineeringHarbin Institute of TechnologyHarbin150001China
- Advanced Microscopy and Instrumentation Research CenterHarbin Institute of TechnologyHarbin150080China
| | | | - Qun Wu
- Department of Microwave EngineeringHarbin Institute of TechnologyHarbin150001China
| | | | - Cheng‐Wei Qiu
- Department of Electrical and Computer EngineeringNational University of SingaporeSingapore117583Singapore
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14
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Akram MR, He C, Zhu W. Bi-layer metasurface based on Huygens' principle for high gain antenna applications. OPTICS EXPRESS 2020; 28:15844-15854. [PMID: 32549420 DOI: 10.1364/oe.393119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
A planar isotropic unit cell based on Huygens' principle is presented for achieving transmission phase control. By tailoring overlapping electric and magnetic resonances with geometry of the proposed unit cell, the transmission phase ranging from 0 - 2π is achieved with high transmittance. The proposed unit cell is then employed to design a metasurface lens with center frequency at 9.3 GHz and a square shaped patch antenna is placed at the focal point of the designed lens to perform conversion from spherical wave front of the source antenna to planar wave front. The designed lens antenna is capable to realize pencil beam radiation pattern with a gain of 19.6 dB and side lobe levels less than -15 dB in simulation. To experimentally verify the proposed design, a prototype of the metasurface lens is fabricated and measured. The measurement results well validate the proposed design and its enhanced performance.
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Akram MR, Ding G, Chen K, Feng Y, Zhu W. Ultrathin Single Layer Metasurfaces with Ultra-Wideband Operation for Both Transmission and Reflection. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1907308. [PMID: 32027428 DOI: 10.1002/adma.201907308] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 01/03/2020] [Indexed: 05/24/2023]
Abstract
Artificially engineered metasurfaces provide extraordinary wave control at the subwavelength scale. However, metasurfaces proposed so far suffer due to limited bandwidths. In this paper, extremely thin metasurfaces made of single metallic layer is experimentally presented for ultra-wideband operation from 9.3 to 32.5 GHz (with a fractional band of 112%), working at both transmission and reflection modes simultaneously. The phase control is achieved by azimuthally rotating the scatterer based on Pancharatnam-Berry phase principle. Nearly uniform efficiency (≈25%), approaching the theoretical limit of the infinitely thin metasurface, is achieved throughout the operation band. Finally, the proposed design is implemented for applications, e.g., the generation of electromagnetic waves carrying orbital angular momentums as well as anomalous reflections and refractions. The metasurfaces are characterized numerically and experimentally and the results are in good agreements.
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Affiliation(s)
- Muhammad Rizwan Akram
- Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Guowen Ding
- School of Electronic Science and Engineering, Nanjing University, Nanjing, 210023, China
| | - Ke Chen
- School of Electronic Science and Engineering, Nanjing University, Nanjing, 210023, China
| | - Yijun Feng
- School of Electronic Science and Engineering, Nanjing University, Nanjing, 210023, China
| | - Weiren Zhu
- Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
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16
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Long H, Niu L, Wang K, Zhao W, Hong X, Liu W, Wang B, Lu P. Generation of second harmonic Bessel beams through hybrid meta-axicons. OPTICS EXPRESS 2020; 28:3179-3189. [PMID: 32121991 DOI: 10.1364/oe.384699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/05/2020] [Indexed: 06/10/2023]
Abstract
Bessel beams are of great potential applications in many fields due to their non-diffraction and self-reconstruction. Here we firstly present a type of nonlinear meta-axicon to generate second harmonic Bessel beams. The nonlinear meta-axicons are based on Au/WS2 hybrid nanostructures. Zero-order and first-order Bessel beams of second harmonic are generated under exciting of 810 nm femtosecond laser. In addition, the performances of the nonlinear meta-axicons, such as the second harmonic generation (SHG) efficiency, non-diffracting distance and full width at half maximum (FWHM) are analyzed theoretically and experimentally. The experimental results are consistent with the predicted, which can enable miniaturized nonlinear optical devices related to generate nonlinear Bessel beams, having potential application in nonlinear optical manipulation, imaging and tractor beams.
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Zhao R, Zhu Z, Dong G, Lv T, Li Y, Guan C, Shi J, Zhang H. High-efficiency Huygens' metasurface for terahertz wave manipulation. OPTICS LETTERS 2019; 44:3482-3485. [PMID: 31305553 DOI: 10.1364/ol.44.003482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 06/06/2019] [Indexed: 06/10/2023]
Abstract
A fair amount of theoretical work has shown that Huygens' metasurfaces well modulate electromagnetic waves by properly designing electrical impedance Zes and magnetic admittance Yms; however, the transmissive Huygens' metasurface is still challenging in the terahertz band. In this work, a transmission-type Huygens' metasurface with bilayer metallic patches has been proposed and theoretically demonstrated to show a reflectionless phase modulation for a linearly polarized terahertz wave. The simulation results show that the metasurface can achieve 2π phase coverage, and importantly the phase change can be simply achieved by changing a single geometric parameter of the metamolecule, along with a similar transmission effect. We design a high-efficiency beam deflector to realize an anomalous refraction with an angle of 19.8°. The proposed metasurface will provide a simple and direct way to realize efficient terahertz devices for wavefront manipulation.
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