1 西安建筑科技大学机电工程学院，西安 710055
2 西安建筑科技大学力学技术研究院，西安 710055
在地球中传播的地震波主要有体波和表面波，而表面波中Rayleigh波对建筑物造成的破坏最为强烈。针对Rayleigh波的振动控制，提出一种田字形超材料结构。相比于传统的地震超材料，这种超材料屏障是由外部口字形框体内部嵌套十字形柱体组成，形成4个可填充区域，其外部框体采用部分埋入的方式，具有高强度、强稳定性、填充方式灵活的特点。应用有限元法计算了田字形超材料的能带结构和传输特性，并通过分析带隙边界处模态振型可知，带隙的打开是由于柱体的局域共振。结合带隙机理可知，柱体结构中土壤填充量不同可改变柱体的质量，形成不同的谐振频率，产生甚低频带隙。为进一步拓宽带隙，设计研究了正、负梯度的质量填充方式，均可得到3.3~13.1 Hz甚低频宽带隙，在谐振频率范围内两者的隔震方式分别为Rayleigh波彩虹捕获和Rayleigh波到体波的转化。最后，采用EI-Centro地震波对填充屏障进行了时程验证，加速度最大幅值衰减超过80%，为地震超材料在减震隔震方面应用提供了新的设计思路和方法。
地震超材料 振动控制 带隙 局域共振 减震隔震 声子晶体 甚低频 seismic metamaterial vibration control band gap local resonance seismic isolation phononic crystal very low frequency
Author Affiliations
Abstract
1 Henan Key Laboratory of Infrared Materials & Spectrum Measures and Applications, School of Physics, Henan Normal University, Xinxiang 453007, China
2 e-mail: lixia_li@htu.edu.cn
3 e-mail: liuyufang2005@126.com
Magneto-plasmonic sensors based on surface plasmon resonance have been studied considerably in recent years, as they feature high sensitivity and ultrahigh resolution. However, the majority of such investigations focus on prism-based sandwich architectures that not only impede the miniaturization of devices but also have a weak transverse magneto-optical Kerr effect (TMOKE) in magnitude. Herein, we theoretically demonstrate a magneto-plasmonic sensor composed of Au/Co bilayer nanodisk arrays on top of optically thick metallic films, which supports a narrow surface plasmon resonance (SPR) with a bandwidth of 7 nm and allows for refractive index sensitivities as high as 717 nm/RIU. Thanks to the high-quality SPR mode, a Fano-like TMOKE spectrum with a subnanometer bandwidth can be achieved in the proposed structure, thereby giving rise to ultrahigh sensing of merit values as large as 7000 in water. Moreover, we demonstrate a large TMOKE magnitude that exceeds 0.6. The value is 1 order of magnitude larger than that of magneto-plasmonic sensors reported. We also demonstrate that the behavior of TMOKE spectra can be controlled by tuning the geometrical parameters of the device including the diameter and thickness of nanodisk arrays. This work provides a promising route for designing magneto-plasmonic sensors based on metasurfaces or metamaterials.
Photonics Research
2020, 8(11): 11001742
1 西南大学物理科学与技术学院, 重庆 400715
2 成都信息工程大学电子工程学院, 四川 成都 610225
提出一种柔性超薄吸透一体化电磁窗结构的设计方法,其能够在宽入射角范围内吸收任意极化的电磁波,并且在特定频段内具有几乎透明的透射窗口。测试结果表明,该结构在4.46 GHz时吸收率为93%,在2.86 GHz时透射率为98%,对应的插入损耗为0.09 dB。样品的整体厚度为0.288 mm,超薄的厚度使得该结构柔性可弯曲,易与曲面目标共形。在此基础上,提出宽带吸透一体化电磁窗结构的设计方法,仿真结果表明,在7.7~12.2 GHz吸收率都能达到90%,在4.35 GHz时透射率为90%,且具有宽入射角特性。
光学器件 电磁窗结构 吸透一体化 低插入损耗 柔性可弯曲 极化无关 光学学报
2019, 39(12): 1223005
Author Affiliations
Abstract
College of Physics and Optoelectrical Engineering, Dalian University of Technology, Dalian, 116023, China
Optical fiber based SPR sensors have attracted more and more attention due to their unique advantages over the prism-based SPR sensors. A novel fiber-optic SPR sensor with multi-alternating metal layers for biochemical analysis is presented in this paper. Based on the fundamental SPR theory of the fiber optic sensing technology, we theoretically investigated the effects of the existence of alternating layers deposited on sensing region SPR wavelength changes. The emphasis was placed on the numerical simulation of the fiber-optic SPR sensor’s sensitivity which could be affected by its technical parameters such as the metal thickness, number of alternating layers. Results showed that, compared to the normal SPR sensor with the single metal layer, the proposed sensor had a wider detecting range of the refractive index and higher sensitivity, which can find applications in biological analysis.
Surface plasmon resonance fiber optics biological detection alternating metal layers Photonic Sensors
2013, 3(3): 202
本文首次报道了五磷酸镨晶体的喇曼光谱,研究了喇曼谱随温度变化情况,以软模变化研究了该晶体的铁弹相变.并观察了不同组分五磷酸镧镨晶体在不同温度下的喇曼谱.
五磷酸镨晶体 喇曼谱 铁弹相变
