共查询到19条相似文献,搜索用时 93 毫秒
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Christian Helgert Thomas Pertsch Carsten Rockstuhl Ekaterina Pshenay-Severin Christoph Menzel Ernst-Bernhard Kley Arkadi Chipouline Christoph Etrich Uwe Huebner Andreas Tuennermann Falk Lederer 《中国光学与应用光学文摘》2010,(1)
In this contribution we review our latest achievements of combined experimental and theoretical studies to tailor the properties of optical metamaterials(MMs) at will. We give three examples of metamaterial designs that have been realized by means of electron-beam lithography and whose spectroscopic characteristics have been comprehensively investigated. In every case, our experiments are complemented by rigorous numerical simulations. Particular emphasis is put on the significance of such tailored effectiv... 相似文献
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We report the design and simulation of a dual-band perfect terahertz absorber which is composed of an electric Split-Resonance-Ring(eSRR) layer, polyimide spacer and a metal plate layer. The absorber has two near-unity absorptions near 0. 502 THz and 0. 942 THz and both are related to the LC resonance of the eSRR. The results show that the designed terahertz absorber is an excellent electromagnetic wave concentrator. The electromagnetic waves are firstly converged into the spacer and the eSRR layer and are then significantly absorbed. 相似文献
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p型GaAs的远红外波段光学特性 总被引:1,自引:0,他引:1
砷化镓(GaAs)是太赫兹波段半导体异质结构激光器的重要材料之一,为了获得p型GaAs材料在远红外波段的光学特性,采用气态源分子束外延(GSMBE)技术在半绝缘GaAs(100)衬底上生长了掺Be的p型GaAs薄膜材料,其载流子浓度从1.54×1015~1.85×1019cm-3。用远红外变换傅里叶光谱仪测量了其远红外反射光谱,并对反射光谱进行了理论模拟和分析,计算得出了不同空穴浓度的p型GaAs在远红外波段的折射率、消光系数和吸收系数。发现在这一波段消光系数和吸收系数均随着载流子浓度的增加而增大,吸收系数最大值可达到4.0×104cm-1。 相似文献
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聚合物弥散液晶材料在1550nm的电光特性研究 总被引:2,自引:0,他引:2
实验研究了不同配方及工艺条件下,聚合物弥散液晶(PDLC)材料在1550nm处的电控光透射特性。由此筛选合适的配方和工艺,研制了聚合物弥散液晶电控可调光衰减器样品。实验说明,在1550nm工作点,50%左右合适的液晶含量的聚合物弥散液晶样品能够获得更好的电控光学性能。采用配方质量比ω(DHPA):ω(E7):ω(RB):ω(NVP):ω(NPG)=100:100:3:2:1.5的配方,制作在1550nm工作的聚合物弥散液晶光衰减器样品。经检测,输入光源为1550mm,223μW时,器件插入损耗为2.3dB,衰减调节范围为13dB,线性工作区域为20~70V。 相似文献
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提出了一种利用含有负介电常量和磁导率张量的各向异性超常材料实现偏振分离的方法。通过分析电磁波在无损耗各向异性超常材料中的传输性质以及透射率与入射角度的关系,分类比较了由不同符号的介电常量和磁导率张量组合而成具有不同波矢面的各向异性超常材料的偏振分离特性,比较结果表明波矢面为单叶双曲面和椭球双叶双曲面的各向异性超常材料的偏振分离特性强。前者可以实现入射波中的s分量和p分量中某一分量正折射,另一分量负折射,且在一定条件下可以同时全透射,从而实现大角度偏振分离。后者在一定条件下可实现入射波中的s分量和p分量某一分量全反射,另一分量全透射,从而实现偏振分离。最后,对从各向同性介质入射到这两种各向异性超常材料中的高斯光波的传输进行了模拟计算,结果表明这两种各向异性超常材料可以实现很好的偏振分离功能,有潜力成为新型的偏振分离元件。 相似文献
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Based on the quantization scheme of the radiation fields in the dispersive and absorptive magnetic media, the normally ordered correlation functions of the outgoing field through a metamaterial plate are obtained. Then the relative photon-number densities of the transmitted field, the reflected field and the absorbed field are gotten through the correlation functions. Furthermore, the contributions of the relative permittivity and permeability of the metamaterials to the transmission are analyzed. Our results show that the permittivity and permeability reinforce the transmission for frequencies that are big compared with the magnetic resonance frequency. 相似文献
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N. P. Johnson A. Z. Khokhar H. M. Chong R. M. De La Rue T. J. Antosiewicz S. McMeekin 《Opto-Electronics Review》2006,14(3):187-191
Although metamaterials and so-called left-handed media have originated from theoretical considerations, it is only by their
practical fabrication and the measurement of their properties that they have gained credibility and can fulfil the potential
of their predicted properties. In this review we consider some of the more generally applicable fabrication methods and changes
in geometry as they have progressed, exhibiting resonant frequencies ranging from radio waves to the visible optical region.
An erratum to this article is available at . 相似文献
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B. Wood 《Laser \u0026amp; Photonics Reviews》2007,1(3):249-259
Metamaterials are artificial materials structured on a subwavelength scale to provide electromagnetic properties beyond those available in nature. Progress in this young field has been startlingly swift. The last year alone has seen the realization of the first optical negative‐index metamaterials and the constructon of two very striking metamaterial‐based devices: an invisibility cloak and a far‐field lens capable of subwavelength imaging. Here, I review these developments and the key concepts that made them possible. 相似文献
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Hafiz T.Ali MRamzan M Imran Arshad Nicola A.Morley M.Hassan Abbas Mohammad Yusuf Atta Ur Rehman Khalid Mahmood Adnan Ali Nasir Amin MAjaz-un-Nabi 《中国物理 B》2022,31(2):27502-027502
We investigate the impact of Ni insertion on the structural,optical,and magnetic properties of Ba0.8La0.2Fe12-xNixO19hexaferrites(Ni substituted La-BaM hexaferrites).Samples were prepared using the conventional co-precipitation method and sintered at 1000℃for 4 hours to assist the crystallization process.An analysis of the structure of the samples was carried out using an x-ray diffraction(XRD)spectrometer.The M-type hexagonal structure of all the samples was confirmed using XRD spectra.The lattice parameters a and c were found to be in the ranges of 5.8925±0.001 nm–5.8952±0.001 nm and 23.2123±0.001 nm–23.2219±0.001 nm,respectively.The M-type hexagonal nature of the prepared samples was also indicated by the presence of corresponding FT-IR bands and Raman modes in the FT-IR and Raman spectra,respectively.EDX results confirmed the successful synthesis of the samples according to the required stoichiometric ratio.A UV-vis spectrometer was used to record the absorption spectra of the prepared samples in the wavelength range of 200 nm–1100 nm.The optical energy bandgap of the samples was found to be in the range of 1.21 eV–3.39 eV.The M–H loops of the samples were measured at room temperature at an applied magnetic field range of 0 kOe–60 kOe.A high saturation magnetization of 99.92 emu/g was recorded in the sample with x=0 at a microwave operating frequency of 22.2 GHz.This high value of saturation magnetization is due to the substitution of La3+ions at the spin-up(12k,2a,and 2b)sites.The Ni substitution is proven to be a potential candidate for the tuning of the optical and magnetic parameters of M-type hexaferrites.Therefore,we suggest that the prepared samples are suitable for use in magneto-optic applications. 相似文献
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《中国物理 B》2021,30(9):96103-096103
Based on Dirac semimetal metamaterials, the tunable plasmon induced transparency(PIT) is investigated elaborately in this work. The designed unit cell consists of a strip and a square bracket, which is periodically aligned on the dielectric substrate. Our numerical results illustrate that a pronounced transparency window exists due to near field coupling between two bright modes, which can be dynamically tuned with Fermi energy. Namely, the transparency window demonstrates a distinct blue shift with a larger Fermi energy. Moreover, an on-to-off switch of the PIT transparency window is realized with different polarization angles. In addition, the accompanied slow light property is examined with the calculation of phase and group delay. Finally, a small variation of the refractive index of the substrate can induce a clear movement of the PIT transparency window which delivers a guidance in the application of optical sensing. Thus, this work provides us a new strategy to design compact and adjustable PIT devices and has potential applications in highly tunable optical switchers,sensors, and slow light devices. 相似文献