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An ultrathin and dual-band bidirectional metasurface absorber based on ring-disk resonators

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Abstract

In this paper, an ultrathin and dual-band bidirectional metasurface absorber (MSA) based on ring-disk (RD) resonators structure. The simulation results indicate that the proposed MSA can achieve a high absorbance of 95.1% and 93.6% at 6.64 GHz and 13.36 GHz, respectively, for both forward (+ z) and backward (− z) incidences, which is effectively validated by the experiment. The retrieved equivalent electromagnetic (EM) parameters and simulated surface current distributions demonstrate that the dual-band high absorption is mainly attributed to the fundamental dipolar resonance excited by the ring-shape (RP) and disk-shape (DS) resonators, respectively. Moreover, the designed bidirectional MSA can achieve wide-angle absorption for both transverse electric (TE) and transverse magnetic (TM) modes. Furthermore, the absorption performance of the bidirectional MSA can be tuned by varying the geometrical parameters of the unit-cell structure. The proposed dual-band bidirectional MSA has promising application prospects in detection, sensing, and imaging.

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Data underlying the results presented in this paper are not publicly available at this time but may be obtained from the authors upon reasonable request.

References

  1. S. Sun, Q. He, J. Hao, S. Xiao, L. Zhou, Electromagnetic metasurfaces: physics and applications. Adv. Opt. Photon. 11(2), 380–479 (2019)

    Google Scholar 

  2. X. Ni, Z. Wong, M. Mrejen, Y. Wang, X. Zhang, An ultrathin invisibility skin cloak for visible light. Science 349, 1310–1314 (2015)

    ADS  PubMed  CAS  Google Scholar 

  3. L. Li, X. Zhang, C. Song, Y. Huang, Progress, challenges, and perspective on metasurfaces for ambient radio frequency energy harvesting. Appl. Phys. Lett. 116(6), 060501 (2020)

    ADS  CAS  Google Scholar 

  4. N. Fang, H. Lee, C. Sun, X. Zhang, Sub-diffraction-limited optical imaging with a silver superlens. Science 308, 534–537 (2005)

    ADS  PubMed  CAS  Google Scholar 

  5. X. Zhu, Y. Cheng, J. Fan, F. Chen, H. Luo, L. Wu, Switchable efficiency terahertz anomalous refraction and focusing based on graphene metasurface. Diam. Relat. Mater. 121, 108743 (2022)

    ADS  CAS  Google Scholar 

  6. W. Ye, F. Zeuner, X. Li, B. Reineke, S. He, C. Qiu, J. Liu, Y. Wang, S. Zhang, T. Zentgraf, Spin and wavelength multiplexed nonlinear metasurface holography. Nat. Commun. 7, 11930 (2016)

    ADS  PubMed  PubMed Central  CAS  Google Scholar 

  7. Y. Shah, J. Grant, D. Hao, M. Kenney, V. Pusino, D. Cumming, Ultra-narrow line width polarization-insensitive filter using a symmetry-breaking selective plasmonic metasurface. ACS Photonics 5, 663–669 (2018)

    CAS  Google Scholar 

  8. Y. Luo, J. Yu, Y. Cheng, F. Chen, H. Luo, A compact microwave bandpass filter based on spoof surface plasmon polariton and substrate integrated plasmonic waveguide structures. Appl. Phys. A 128(6), 97 (2022)

    ADS  CAS  Google Scholar 

  9. S. Sun, Y. Cheng, H. Luo, F. Chen, X. Li, Notched-wideband bandpass filter based on spoof surface plasmon polaritons loaded with resonator structure. Plasmonics 18, 165–174 (2023)

    Google Scholar 

  10. H. Zhang, Y. Cheng, F. Chen, Quad-band plasmonic perfect absorber using all-metal nanostructure metasurface for refractive index sensing. Optik 229, 166300 (2021)

    ADS  CAS  Google Scholar 

  11. Z. Li, Y. Cheng, H. Luo, F. Chen, X. Li, Dual-band tunable terahertz perfect absorber based on all-dielectric InSb resonator structure for sensing application. J. Alloy. Compd. 925, 166617 (2022)

    CAS  Google Scholar 

  12. J. Zhao, Y. Cheng, Temperature-tunable terahertz perfect absorber based on all-dielectric strontium titanate (STO) resonator structure. Adv. Theory Simul. 5, 2200520 (2022)

    CAS  Google Scholar 

  13. N. Li, J. Zhao, P. Tang, Y. Cheng, Broadband and high-efficient reflective linear-circular polarization convertor based on three-dimensional all-metal anisotropic metamaterial at terahertz frequencies. Opt. Commun.Commun. 538, 129544 (2023)

    Google Scholar 

  14. J. Zhao, N. Li, Y. Cheng, All-dielectric InSb metasurface for broadband and high-efficient thermal tunable terahertz reflective linear-polarization conversion. Opt. Commun.Commun. 536, 129372 (2023)

    CAS  Google Scholar 

  15. N. Li, J. Zhao, P. Tang, Y. Cheng, Design of all-metal 3D anisotropic metamaterial for ultrabroadband terahertz reflective linear polarization conversion. Phys. Status Solidi B 260, 2300104 (2023)

    ADS  CAS  Google Scholar 

  16. D. Yang, Y. Cheng, H. Luo, F. Chen, L. Wu, Ultrathin and ultra-broadband terahertz single-layer metasurface based on double-arrow-shaped resonator structure for full-space wavefront manipulation. Adv. Theory Simul. 5, 2300162 (2023)

    Google Scholar 

  17. C. Ni, L. Dong, Z. Xu, M. Wang, L. Wu, Y. Cheng, Broadband and high-efficiency thermal switchable InSb metasurface for terahertz wave anomalous reflection and focusing effect. Mater. Today Commun. 35, 106305 (2023)

    CAS  Google Scholar 

  18. Q. Pu, Z. Cheng, C. Ni, L. Wu, Y. Cheng, Broadband all-metal reflective-mode geometric metasurfaces for visible multi-functional wavefront manipulation. Physica B 666, 415097 (2023)

    CAS  Google Scholar 

  19. N.I. Landy, S. Sajuyigbe, J.J. Mock, D.R. Smith, W.J. Padilla, Perfect metamaterial absorber. Phys. Rev. Lett. 100, 207402 (2008)

    ADS  PubMed  CAS  Google Scholar 

  20. C.M. Watts, X. Liu, W.J. Padilla, Metamaterial electromagnetic wave absorbers. Adv. Mater. 24(23), OP98–OP120 (2012)

    PubMed  CAS  Google Scholar 

  21. S. Luo, J. Zhao, D. Zuo, X. Wang, Perfect narrow band absorber for sensing applications. Opt. Express 24, 9288–9294 (2016)

    ADS  PubMed  CAS  Google Scholar 

  22. W. Dong, R. Liu, Y. Li, Z. Yang, L. Chang, R. Ma, Y. Han, Ultra-narrow band perfect absorber and its application as plasmonic sensor in the visible region. Nanoscale Res. Lett. 12, 427 (2017)

    ADS  Google Scholar 

  23. Z. Li, X. Sun, C. Ma, J. Li, X. Li, B. Guan, K. Chen, Ultra-narrow-band metamaterial perfect absorber based on surface lattice resonance in a WS2 nanodisk array. Opt. Express 29(17), 27084–27091 (2021)

    ADS  PubMed  CAS  Google Scholar 

  24. G. Cui, J. Lv, Predictable infrared dual-band narrow-band absorber for infrared detection. Nanotechnology 33, 335705 (2022)

    Google Scholar 

  25. Y. Cheng, F. Chen, H. Luo, Triple-band perfect light absorber based on hybrid metasurface for sensing application. Nanoscale Res. Lett. 15, 1, 103 (2020)

  26. X. Wang, Q. Wang, G. Dong, Y. Hao, M. Lei, K. Bi, Multi-band terahertz metasurface absorber. Phys. Lett. B 31, 0217–9849 (2017)

    Google Scholar 

  27. A. Yousaf, M. Murtaza, A. Wakeel, S. Anjum, A highly efficient low-profile tetra-band metasurface absorber for X, Ku, and K band applications. Int. J. Electron. Commun. (AEÜ) 154, 154329 (2022)

    Google Scholar 

  28. Y. Cheng, J. Zhao, Simple design of a six-band terahertz perfect metasurface absorber based on a single resonator structure. Phys. Scr. 97, 095508 (2022)

    ADS  Google Scholar 

  29. S.K. Dubey, A. Kumar, G. Dayal, A. Pathak, S.K. Srivastava, Polarization insensitive metamaterial based electromagnetic multiband absorber in the long-wave infrared (LWIR) region. Opt. Laser Technol. 156, 108511 (2022)

    CAS  Google Scholar 

  30. P. Yu, L.V. Besteiro, Y. Huang, J. Wu, L. Fu, H.H. Tan, C. Jagadish, G.P. Wiederrecht, A.O. Govorov, Z. Wang, Broadband metamaterial absorbers. Adv. Opt. Mater. 7, 1800995 (2018)

    Google Scholar 

  31. Y. Cheng, H. Zhao, C. Li, Broadband tunable terahertz metasurface absorber based on complementary-wheel-shaped graphene. Opt. Mater. 109, 110369 (2020)

    CAS  Google Scholar 

  32. C. Du, D. Zhou, H. Guo, Y. Pang, H. Shi, W. Liu, J. Su, C. Singh, S. Trukhanov, A. Trukhanov, L. Panina, Z. Xu, Ultra-broadband terahertz metamaterial coherent absorber using multilayer electric ring resonator structures based on antireflection coating. Nanoscale 12, 9769–9775 (2020)

    PubMed  CAS  Google Scholar 

  33. Y. Ma, L. Shi, J. Wang, L. Zhu, Y. Ran, Y. Liu, J. Li, A transparent and flexible metasurface with both low infrared emission and broadband microwave absorption. J. Mater. Sci. Mater. Electron. 32, 2001–2010 (2021)

    CAS  Google Scholar 

  34. C. Quan, J. Zou, C. Guo, W. Xu, Z. Zhu, J. Zhang, High-temperature resistant broadband infrared stealth metamaterial absorber. Opt. Laser Technol. 156, 108579 (2022)

    CAS  Google Scholar 

  35. Z. Zheng, Y. Zheng, Y. Luo, Z. Yi, J. Zhang, Z. Liu, W. Yang, Y. Yu, X. Wu, P. Wu, Switchable terahertz device combining ultra-wideband absorption and ultra-wideband complete reflection. Phys. Chem. Chem. Phys. 24, 2527–2533 (2022)

    PubMed  CAS  Google Scholar 

  36. C. Du, D. Zhou, H. Guo, Y. Pang, H. Shi, W. Liu, C. Singh, S. Trukhanov, A. Trukhanov, Z. Xu, Active control scattering manipulation for realization of switchable EIT-like response metamaterial. Opt. Commun.Commun. 483, 126664 (2021)

    CAS  Google Scholar 

  37. M.V. Zdorovets, A.L. Kozlovskiy, D.I. Shlimas, D.B. Borgekov, Phase transformations in FeCo - Fe2CoO4/Co3O4-spinel nanostructures as a result of thermal annealing and their practical application. J. Mater. Sci. Mater. Electron. 32, 16694–16705 (2021)

    CAS  Google Scholar 

  38. F.G. Agayev, S.V. Trukhanov, A.V. Trukhanov, S.H. Jabarov, GSh. Ayyubova, M.N. Mirzayev, E.L. Trukhanova, D.A. Vinnik, A.L. Kozlovskiy, M.V. Zdorovets, Study of structural features and thermal properties of barium hexaferrite upon indium doping. J. Therm. Anal. Calorim. 147, 14107–14114 (2022)

    CAS  Google Scholar 

  39. A.I. Stognij, N.N. Novitskii, S.V. Trukhanov, A.V. Trukhanov, L.V. Panina, S.A. Sharko, A.I. Serokurova, V.A. Ketsko, V.P. Dyakonov, H. Szymczak, C. Singh, Y. Yang, Interface magnetoelectric effect in elastically linked Co/PZT/Co layered structures. J. Magn. Magn. Mater. 485, 291–296 (2019)

    ADS  CAS  Google Scholar 

  40. I.V. Korolkov, N. Zhumanazar, Y.G. Gorin, A.B. Yeszhanov, M.V. Zdorovets, Enhancement of electrochemical detection of Pb2+ by sensor based on track-etched membranes modified with interpolyelectrolyte complexes. J. Mater. Sci. Mater. Electron. 31, 20368–20377 (2020)

    Google Scholar 

  41. H. He, X. Shang, L. Xu, J. Zhao, W. Cai, J. Wang, C. Zhao, L. Wang, Thermally switchable bifunctional plasmonic metasurface for perfect absorption and polarization conversion based on VO2. Opt. Express 28(4), 4563–4570 (2020)

    ADS  PubMed  Google Scholar 

  42. Z. Gao, C. Xu, X. Tian, J. Wang, H. Zhang, S. Qu, Q. Fan, Broadband and polarization-independent metamaterial absorber based on double square ring structure. Opt. Commun.Commun. 500, 127327 (2021)

    CAS  Google Scholar 

  43. H. Zhang, K. Peng, H. Jiang, W. Li, W. Zhao, Multifunctional metasurfaces for switchable polarization selectivity and absorption. Opt. Express 13(12), 20554–20563 (2022)

    Google Scholar 

  44. Y.Z. Cheng, J. Liu, F. Chen, H. Luo, X. Li, Optically switchable broadband metasurface absorber based on square ring shaped photoconductive silicon for terahertz waves. Phys. Lett. A 402, 127345 (2021)

  45. A. Dhumal, A. Bhardwaj, K.V. Srivastava, Polarization insensitive multilayered broadband absorber for L and S bands of the radar spectrum. Microw. Opt. Technol. Lett. 63(4), 1229–1235 (2022)

    Google Scholar 

  46. Y.L. Liao, Y. Zhao, S. Wu, S. Feng, Wide-angle broadband absorber based on uniform-sized hyperbolic metamaterial. Opt. Mater. Express 8(9), 2484–2493 (2018)

    ADS  CAS  Google Scholar 

  47. S.K. Tseng, H.H. Hsiao, Y.P. Chiou, Wide-angle wideband polarization-insensitive perfect absorber based on uniaxial anisotropic metasurfaces. Opt. Mater. Express 10(5), 1193–1203 (2020)

    ADS  CAS  Google Scholar 

  48. S. Ji, Z. Luo, J. Zhao, H. Dai, C. Jiang, Design and analysis of an ultra-thin polarization-insensitive wide-angle triple-band metamaterial absorber for X-band application. Opt. Quant. Electron. 53(3), 148 (2021)

    CAS  Google Scholar 

  49. A.A.G. Amer, S.Z. Sapuan, A. Alzahrani, N. Nasimuddin, A.A. Salem, S.S. Ghoneim, Design and analysis of polarization-independent, wide-angle, broadband metasurface absorber using resistor-loaded split-ring resonators. Electronics 11, 1986 (2022)

    CAS  Google Scholar 

  50. Y. Cheng, Y. Qian, H. Luo, F. Chen, Z. Cheng, Terahertz narrowband perfect metasurface absorber based on micro-ring-shaped GaAs array for enhanced refractive index sensing. Physica E 146, 115527 (2023)

    CAS  Google Scholar 

  51. F. Wu, P. Shi, Z. Yi, H. Li, Y. Yi, Ultra-broadband solar absorber and high-efficiency thermal emitter from UV to mid-infrared spectrum. Micromachines 14(5), 985 (2023)

    PubMed  PubMed Central  Google Scholar 

  52. Y. Cheng, Y. Qian, Z. Li, H. Homma, A.A. Fathnan, H. Wakatsuchi, The design of metasurface absorber based on the ring-shaped resonator lumped with nonlinear circuit for a pulse wave. J. Electron. Inf. Technol. 45(6), 1–9 (2023)

    Google Scholar 

  53. Y. Zheng, Z. Yi, L. Liu, X. Wu, H. Liu, G. Li, L. Zeng, H. Li, P. Wu, Numerical simulation of efficient solar absorbers and thermal emitters based on multilayer nanodisk arrays. Appl. Therm. Eng. 230, 120841 (2023)

    CAS  Google Scholar 

  54. D. Xiao, K. Tao, Q. Wang, Y. Ai, Z. Ouyang, Metasurface for multiwavelength coherent perfect absorption. IEEE Photonics 9, 6800108 (2017)

    Google Scholar 

  55. S. Huang, Z. Xie, W. Chen, J. Lei, F. Wang, K. Liu, L. Li, Metasurface with multi-sized structure for multi-band coherent perfect absorption. Opt. Express 26, 7066 (2018)

    ADS  PubMed  CAS  Google Scholar 

  56. W. Kang, Q. Gao, L. Dai, Y. Zhang, H. Zhang, Y. Zhang, Dual-controlled tunable terahertz coherent perfect absorption using Dirac semimetal and vanadium dioxide. Result Phys. 19, 103688 (2020)

    Google Scholar 

  57. T. Zhou, S. Wang, Y. Meng, S. Wang, Y. Ou, H. Li, H. Liu, X. Zhai, S. Xia, L. Wang, Dynamically tunable multi-band coherent perfect absorption based on InSb metasurfaces. J. Phys. D Appl. Phys. 54, 435103 (2021)

    ADS  CAS  Google Scholar 

  58. T. Li, B.Q. Chen, Q. He, L.A. Bian, X.J. Shang, G.F. Song, Polarization-selective bidirectional absorption based on a bilayer plasmonic metasurface. Materials 13, 5298 (2020)

    ADS  PubMed  PubMed Central  CAS  Google Scholar 

  59. Z. Li, W. Liu, C. Tang, H. Cheng, Z. Li, Y. Zhang, J. Li, S. Chen, J. Tian, A bilayer plasmonic metasurface for polarization-insensitive bidirectional perfect absorption. Adv. Theory Simul. 3(2), 1900216 (2020)

    CAS  Google Scholar 

  60. L. Stephen, N. Yogesh, V. Subramanian, Realization of bidirectional, bandwidth-enhanced metamaterial absorber for microwave applications. Sci. Rep. 9, 10058 (2019)

    ADS  PubMed  PubMed Central  Google Scholar 

  61. H. Lin, Y. Wu, J. Xiong, R. Zhou, Q. Li, R. Tang, Dual-polarized bidirectional three-dimensional metamaterial absorber with transmission windows. Opt. Express 29(25), 40770–40780 (2021)

    ADS  Google Scholar 

  62. X. Ming, X. Liu, L. Sun, W.J. Padilla, Degenerate critical coupling in all-dielectric metasurface absorbers. Opt. Express 25(20), 24658–24669 (2017)

    ADS  PubMed  CAS  Google Scholar 

  63. A.V. Trukhanov, N.A. Algarou, Y. Slimani, M.A. Almessiere, A. Baykal, D.I. Tishkevich, D.A. Vinnik, M.G. Vakhitov, D.S. Klygach, M.V. Silibin, T.I. Zubar, S.V. Trukhanov, Peculiarities of the microwave properties of hard-soft functional composites SrTb0.01Tm0.01Fe11.98O19-AFe2O4 (A = Co, Ni, Zn, Cu and Mn). RSC Adv. 10(51), 32638 (2020)

    ADS  PubMed  PubMed Central  CAS  Google Scholar 

  64. A.Z. Tuleushev, F.E. Harrison, A.L. Kozlovskiy, M.V. Zdorovets, Evolution of the absorption edge of PET films irradiated with Kr ions after thermal annealing and ageing. Opt. Mater. 119, 111348 (2021)

    CAS  Google Scholar 

  65. S.V. Trukhanov, L.S. Lobanovski, M.V. Bushinsky, V.A. Khomchenko, N.V. Pushkarev, I.O. Tyoyanchuk, A. Maignan, D. Flahaut, H. Szymczak, R. Szymczak, Influence of oxygen vacancies on the magnetic and electrical properties of La1–xSrxMnO3–x/2 manganites. Eur. Phys. J. B. 42, 51–61 (2004)

    ADS  CAS  Google Scholar 

  66. A. Kozlovskiy, K. Egizbek, M.V. Zdorovets, M. Ibragimova, A. Shumskaya, A.A. Rogachev, Z.V. Ignatovich, K. Kadyrzhanov, Evaluation of the efficiency of detection and capture of manganese in aqueous solutions of FeCeOx nanocomposites doped with Nb2O5. Sensors 20, 4851 (2020)

    ADS  PubMed  PubMed Central  CAS  Google Scholar 

  67. X. Jiang, T. Wang, S. Xiao, X. Yan, L. Cheng, Tunable ultra-high-efficiency light absorption of monolayer graphene using critical coupling with guided resonance. Opt. Express 25(22), 27028–27036 (2017)

    ADS  PubMed  CAS  Google Scholar 

  68. C.L. Cen, Z.Q. Chen, D.Y. Xu, L.Y. Jiang, X.F. Chen, Z. Yi, P.H. Wu, G.F. Li, Y.G. Yi, High quality factor, High sensitivity metamaterial graphene—perfect absorber based on critical coupling theory and impedance matching. Nanomaterials 10(1), 95 (2020)

    PubMed  PubMed Central  CAS  Google Scholar 

  69. D.R. Smith, S. Schultz, P. Markos, C.M. Soukoulis, Determination of effective permittivity and permeability of metamaterials from reflection and transmission coefficients. Phys. Rev. B 65, 195104 (2002)

    ADS  Google Scholar 

  70. Y. Cheng, Y. Qian, H. Homma, A.A. Fathnan, H. Wakatsuchi, Waveform-selective Metasurface Absorber with a Single-patch Structure and Lumped Nonlinear Circuit for a Higher-order Mode. IEEE Trans. Antennas Propag.Propag. 71(11), 8677–8691 (2023)

    ADS  Google Scholar 

  71. Y. Xiong, F. Chen, Y. Cheng, H. Luo, Rational design and fabrication of optically transparent broadband microwave absorber with multilayer structure based on indium tin oxide. J. Alloy. Compd. 920, 166008 (2022)

    CAS  Google Scholar 

  72. A. Rastgordani, Z.G. Kashani, M.S. Abrishamian, A general equivalent circuit model for plasmonic metasurface broadband absorbers. Optik 221, 165354 (2020)

    ADS  CAS  Google Scholar 

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  1. Institute of Defense Engineering, Academy of Military Science of the PLA, Beijing, 100036, People’s Republic of China

    Bingzhen Li, Yuhua Chen, Qingqing Wu, Yan Li, Jijun Wang, Fangyuan Li & Ning Li

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  1. Bingzhen Li
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  2. Yuhua Chen
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Contributions

JW, FL and NL conceived the idea and set up the model; BL performed the calculations, experiment and composed the first draft of the manuscript; YC and QW refined the model, and provided helpful discussions; YL and JW coordinated the work. All authors have contributed to writing the manuscript. All authors have read and agreed to the published version of the manuscript.

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Correspondence to Jijun Wang.

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Li, B., Chen, Y., Wu, Q. et al. An ultrathin and dual-band bidirectional metasurface absorber based on ring-disk resonators. Appl. Phys. A 130, 125 (2024). https://doi.org/10.1007/s00339-023-07240-6

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