-
Metasurfaces can realize flexible modulation of electromagnetic waves at the wavelength level. However, the reported functions of metasurface are usually fixed and cannot be changed, once its structural design is completed. The designed metasurface cannot meet the requirements for flexible regulation of terahertz waves. We find that the phase change material of vanadium dioxide can achieve a transition from insulating state to metallic state through thermal, electrical, or light excitation, and the phase transition of this material is reversible. Therefore, using vanadium dioxide to form a composite metasurface can achieve dynamic modulation of terahertz waves. In this study, we propose a terahertz metasurface with switchable broadband absorption and polarization conversion. The proposed metasurface is composed of a 9-layer structure stacked from bottom to top with a combination pattern of different dielectric layers. By adjusting the conductivity of vanadium dioxide, the designed metasurface can achieve flexible switching between terahertz wave absorption function and polarization conversion function. When the vanadium dioxide is in the metal state, the designed metasurface behaves as a broadband absorber with an absorption rate of more than 90% in a range of 6.32–18.06 THz and a relative bandwidth of 96.3%. When the vanadium dioxide is in the insulated state, the designed structure acts as a polarization converter in a frequency range of 2.41–3.42 THz, 4.78–7.48 THz, and 9.53–9.73 THz, respectively, with a polarization conversion rate of over 90%. We believe that this metasurface structure will have good applications in the fields of terahertz wave detection, terahertz switches, terahertz filtering, terahertz communication, and terahertz sensing.
-
Keywords:
- terahertz /
- metasurface /
- broadband absorption /
- polarization conversion
-
图 1 超宽带太赫兹吸收器与偏振转换器结构示意图 (a) 周期和单元结构; (b) VO2-QR层俯视图; (c) VO2-R层俯视图; (d) 135°不对称十字形金带层俯视图; (e) 45°不对称十字形金带层俯视图
Fig. 1. The schematic of the ultrabroadband terahertz absorber and polarization converter: (a) Unit cell; (b) top view of the VO2-QR layer; (c) top view of the VO2-R layer; (d) top view of the 135° asymmetrical cross-shaped gold strip; (e) top view of the 45° asymmetrical cross-shaped gold strip.
图 2 (a) 超表面结构的吸收、反射、透射曲线; (b) 超表面结构的等效阻抗实部和虚部曲线
Fig. 2. (a) Absorption, reflection, and transmission curves of the proposed metasurface; (b) equivalent impedance real and imaginary curves of the proposed metasurface.
图 3 (a), (b)电场分布俯视图; (c), (d)磁场分布侧视图
Fig. 3. (a), (b) Top view of electric field distribution; (c), (d) side view of magnetic field distribution.
图 4 (a) 垂直入射下, 宽带吸收器在不同偏振角下的吸收光谱; (b) TE模式下吸收器在不同入射角下的吸收光谱; (c) TM模式下吸收器在不同入射角下的吸收光谱
Fig. 4. (a) Absorption spectra of ultra-broadband absorber at various polarization angles under normal incidence; (b) absorption spectra of absorber at various incidence angles in TE mode; (c) absorption spectra of absorber at various incidence angles in TM mode.
图 5 不同电导率二氧化钒的太赫兹波吸收曲线
Fig. 5. Terahertz wave absorption curves with different conductivities of VO2.
图 6 (a) x偏振波入射下的反射系数; (b)极化转换率PCR
Fig. 6. (a) Reflection coefficients under x-polarized wave normal incidence; (b) polarization conversion rate PCR.
图 7 当二氧化钒电导率为20 S/m时, 不对称十字形金带的几何参数l1(a), l2(b)和介质MF2的厚度t2(c), t4(d)对PCR的影响
Fig. 7. Geometrical parameters influence on polarization conversion rate (PCR) when the conductivity of VO2 is σ = 20 S/m: (a) l1; (b) l2; (c) t2; (d) t4.
图 8 (a)—(c)极化转换器的表面电流分布; (d)—(f)极化转换器的磁场分布
Fig. 8. (a)–(c) Surface current distribution of the polarization converter; (d)–(f) magnetic field distribution of the polarization converter.
图 9 该超表面结构的潜在制造工艺流程图
Fig. 9. Flow chart of potential fabrication process of the proposed metasurface structure.
表 1 本文工作与先前报道成果对比
Table 1. Comparison of the work with previously reported results.
文献 可调材料 功能 性能 带宽 [25] 二氧化钒 宽带吸收 5.8—17.2 THz: A≥90% 吸收11.4 THz [26] 二氧化钒 极化转换 1.08—3.22 THz: PCR≥90% 极化转换2.14 THz [27] 二氧化钒 窄带吸收、极化转换 1.6 THz: A≈100%
0.67—1.99 THz: PCR≥90%单频点吸收
极化转换1.32 THz[28] 二氧化钒 宽带吸收、极化转换 0.78—1.81 THz: A≥90%
0.51—1.45 THz:
PCR≥90%吸收1.03 THz
极化转换0.94 THz本文 二氧化钒 宽带吸收、极化转换 6.32—18.06 THz: A≥90%
2.41—3.42 THz,
4.78—7.48 THz和9.53—9.73 THz: PCR≥90%吸收11.74 THz
极化转换3.91 THz
下载: 导出CSV
-
[1] Chen Z, Chen J J, Tang HW, Shen T, Zhang H 2022 Opt. Express 30 6778
Google Scholar
[2] Wu C Y, Fang Y Q, Luo L B, Guo K, Guo Z Y 2020 Mod. Phys. Lett. B 34 2050292
[3] Barkabian M, Sharifi N, Granpayeh N 2021 Opt. Express 29 20160
Google Scholar
[4] Wu X L, Zheng Y, Luo Y, Zhang J G, Yi Z, Wu X W, Cheng S B, Yang W X, Yu Y, Wu P H 2021 Phys. Chem. Chem. Phys. 23 26864
Google Scholar
[5] He X Y, Liu F, Lin F T, Shi W Z 2021 J. Phys. D: Appl. Phys. 54 235103
Google Scholar
[6] Yi N N, Zong R, Qian R R 2022 Mater. Sci. Semicond. Process. 146 106682.
Google Scholar
[7] Wang J Y, Yang R C, Li Z H, Tian J P 2022 Opt. Mater. 124 111953
Google Scholar
[8] Xu J, Tang J, Cheng Y, Chen M, Wang H X, Xiong J F, Wang T R, Wang S Z, Zhang Y D, Wen H, Qu S L, Yuan L B 2022 Opt. Express 30 17008
Google Scholar
[9] Dong T L, Zhang Y, Li Y, Tang Y P, He X J 2023 Results Phys. 45 106246
Google Scholar
[10] Liu W W, Xu J S, Song Z Y 2021 Opt. Express 29 23331
Google Scholar
[11] Yu F Y, Zhu J B, Shen X B 2022 Opt. Mater. 123 111745
Google Scholar
[12] Zhao Y J, Yang R C, Wang Y X, Zhang W M, Tian J P 2022 Opt. Express 30 27407
Google Scholar
[13] Li C Q, Song Z Y 2023 Opt. Laser Technol. 157 108764
Google Scholar
[14] Liu L, Huang R, Ouyang Z B 2021 Opt. Express 29 20839
Google Scholar
[15] Jiang Y Y, Zhang M, Wang W H, Song Z Y 2022 Phys. Scr. 97 015501
Google Scholar
[16] Niu J H, Yao Q Y, Mo W, Li C H, Zhu A J 2023 Opt. Commun. 527 128953
Google Scholar
[17] Peng Z, Zheng Z S, Yu Z S, Lan H T, Zhang M, Wang S X, Li L, Liang H W, Su H 2023 Opt. Laser Technol. 157 108723
Google Scholar
[18] Lian X J, Ma M T, Tian J P, RYang R C, Wu X T 2023 AEU-Int. J. Electron. C 170 154784
[19] Zhu W, Rukhlenk I D, Premaratn M 2013 Appl. Phys. Lett. 102 241914
Google Scholar
[20] Kang L, Wu Y H, Werner D H 2021 Opt. Express 29 8816
Google Scholar
[21] Ma W Y, Yu S L, Zhao T G 2021 Opt. Commun. 493 127037
Google Scholar
[22] Yu F Y, Zhu J B, Shen X B 2022 Opt. Mater. 123 111745
Google Scholar
[23] Kharintsev S S, Battalova E I, Mukhametzyanov T A, Pushkarev A P, Scheblykin I G, Makarov S V, Potma E O, Fishman D A 2023 ACS Nano 17 9235
Google Scholar
[24] Lian M, Su Y, Liu K, Zhang S J, Chen X Y, Ren H A, Xu Y H, Chen J J, Tian Z, Cao T 2023 Adv. Opt. Mater. 11 2202439
Google Scholar
[25] Zhang P S, Deng X H, Tao L Y, Li P, Lu M, Guo F M, Song Y M, Yuan J R 2023 Opt. Mater. 138 113716
Google Scholar
[26] Feng Z J, Ni B, Ni H B, Zhou X Y, Yang L S, Chang J H 2023 J. Opt. Soc. Am. B 40 2174
Google Scholar
[27] Miao X, Xiao Z Y, Cui Z T, Zheng T T, Wang X Y 2023 Optik 281 170810
Google Scholar
[28] Dong T L, Zhang Y, Li Y, Tang Y P, He, X J 2023 Results Phys. 45 106246
Google Scholar
下载:
计量
- 文章访问数: 263
- PDF下载量: 4
- 被引次数: 0
