Metamaterials
超材料 (Metamaterials) 是指由人工结构功能单元按照特定的空间排布构成的、具有超常宏观物理特性的人工复合材料或复合结构. 超材料是先进功能材料的创新研究范式, 将传统均质材料的半经验式研究手段发展为精确可设计的材料研究范式. 超材料不仅是一种材料新形态, 更是一种材料设计新理念, 即: 类比自然材料电磁、力、热、声等响应的微观机制和自然材料基本构成粒子的空间点阵排布方式, 构造与自然材料原子、分子等类比的人工微结构单元, 通过结构单元的周期性、准周期性或特殊点阵排布构造人工复合材料, 实现自然材料无法实现或很难实现的特殊物理特性. 由于超常的电磁、声、热、力等功能, 超材料在隐身伪装、电子对抗、导航通讯、预警制导、成像识别等领域具有巨大的应用潜力.
超材料研究在国内非常活跃, 总体呈现出百花齐放的局面, 所涵盖领域包括电磁超材料、红外/THz超材料、光学超材料、声学超材料、力学超材料、光学超材料、热学超材料等领域. 2019 年 11 月, 中国材料研究学会超材料分会、中国物理学会电介质物理专业委员会和中国电子学会元件分会联合主办了“第一届全国超材料大会”, 1500 多名国内超材料领域的专家学者和科研工作者参加了大会. 大会推动了我国超材料理论研究、设计与制备研究、器件应用研究, 增进了超材料学术界和工业界之间的学术交流、技术交流与应用推广, 促进了我国超材料研究的知识创新、技术创新以及应用发展.
本专题收录了本届超材料大会的部分优秀论文, 论文涉及到电磁超材料、力学超材料、声波超材料和光学超材料. 希望专题的出版能进一步增进交流, 促进该领域的发展.
超材料研究在国内非常活跃, 总体呈现出百花齐放的局面, 所涵盖领域包括电磁超材料、红外/THz超材料、光学超材料、声学超材料、力学超材料、光学超材料、热学超材料等领域. 2019 年 11 月, 中国材料研究学会超材料分会、中国物理学会电介质物理专业委员会和中国电子学会元件分会联合主办了“第一届全国超材料大会”, 1500 多名国内超材料领域的专家学者和科研工作者参加了大会. 大会推动了我国超材料理论研究、设计与制备研究、器件应用研究, 增进了超材料学术界和工业界之间的学术交流、技术交流与应用推广, 促进了我国超材料研究的知识创新、技术创新以及应用发展.
本专题收录了本届超材料大会的部分优秀论文, 论文涉及到电磁超材料、力学超材料、声波超材料和光学超材料. 希望专题的出版能进一步增进交流, 促进该领域的发展.
2020, 69 (13): 134303.
doi: 10.7498/aps.69.20200368
Abstract +
In this paper, we propose a hybrid subwavelength broadband sound absorber based on micro perforated plate and multiple coiled channels. And the mechanism of low frequency broadband sound absorption of the hybrid sound absorber is analyzed in detail. Based on this, the theoretical analysis model and the finite element numerical analysis model are established, and the mutual verification of theoretical and numerical solutions is completed. The structure can theoretically achieve the low-frequency and high-efficiency sound absorption with an average absorption coefficient of 0.8 in a frequency band of 200–500 Hz when the overall thickness of the sound absorbing structure is 60 mm. At the same time when the overall thickness is 90 mm, quasi-perfect sound absorption with peaks up to 0.95 in a frequency range of 180–350 Hz is realized theoretically. The composite sound absorption structure has a certain application prospect in engineering low frequency noise in future.
2020, 69 (13): 134302.
doi: 10.7498/aps.69.20200364
Abstract +
2020, 69 (13): 134205.
doi: 10.7498/aps.69.20200369
Abstract +
The coupled waveguide-microcavity structure has a wide range of applications in optical filters and optical modulators. The optical transmission properties of structure are mostly determined by the coupling strength of the modes. In the conventional waveguide-microcavity structure, the mode coupling is finished by the form of evanescent field, which is usually achieved by controlling the geometric spacing between waveguide and microcavity. Surface plasmon polaritons are the excitations of the electromagnetic waves coupled to collective oscillations of free electrons in metal. Since the electromagnetic waves are attenuated sharply in the metal, this requires precise control of the spacing between the waveguide and the metal microcavity, and poses a great challenge for controlling the coupling of modes in the metal waveguide-cavity structure. In this paper, we proposed a scheme of using a metal-dielectric-metal waveguide side coupling metal microcavities to overcome this limit. Based on the resonant characteristics of the Fabry–Pérot mode in the metal microcavity, a slit is introduced to connect the waveguide and microcavities. By adjusting the width and the offset location of slits, the leakage rate and coupling strength of the mode in metal microcavity can be controlled. The finite difference frequency domain (FDFD) method was used to numerically simulate the electromagnetic properties of structure. First, we have studied the transmission behaviors of surface plasmon polaritons in the system consisted by metal waveguide and single microcavity. As other microcavity is introduced to the structure and connected the original microcavity by slit, the electromagnetically induced transparency phenomena based on surface plasmon polaritons are demonstrated in the coupled metal waveguide and double microcavities structure. As the width of slit connected the microcavity is increased, the transmission peak of structure and the full width at half maximum of the transparency window also increase accordingly. The change of the geometric parameters of slit will modulate the resonance characteristics of structure, and the corresponding physical mechanism is explained by the temporal coupled mode theory. In our works, the metal waveguide and microcavities are coupled by the energy leakage of microcavities assisted by slits, which breaks the limit of separation distance between metal waveguide and microcavity, and contributes to the manufacture of devices. The results of the paper will have applications in designing the compact photonic devices based on surface plasmon polaritons.
2020, 69 (13): 135201.
doi: 10.7498/aps.69.20200365
Abstract +
The Field transformation (FT) is a novel theory for controlling the polarization and impedance of electromagnetic waves, which is independent on the angle of incidence. Thus, the FT method is superior for wide-angle devices design. In this paper, we propose a wide-angle method for generating vortex beam based on the FT theory. According to this method, an artificial media for vortex beam generation is designed and simulated, which demonstrates the proposed method. The designed artificial media is a multi-layered structure, which can generate vortex beam of order 2 with an incident angle stability up to 60°.
