In this Letter, we report on encoding and display based on stereo standing U-shaped resonator (SUSR) arrays. The SUSR serves as a perfect absorber at a structure-dependent frequency when the polarization of incident light is parallel to the bottom rim of the SUSR. When the incidence polarization is rotated for 90° (perpendicular to the bottom rim of the SUSR), the SUSR turns to a perfect reflector at broadband frequencies. Further, the resonant frequency sensitively depends on the height of the arms of the SUSR. By introducing SUSRs with different arm heights, a resonant absorption state may occur at different frequencies. By defining the resonant absorption state as "dark" and the reflection state as "bright," we can encode and display binary patterns. Beside, when the SUSR rotates with the direction of the standing arms as axis, a different reflectivity, hence, a different shade will be generated. In this way, we may realize a grayscale display. Experimentally, we demonstrate that this encoding and display scheme indeed works.

Zheng Han Wang;Yuan Sheng Hu;Xiang Xiong;茹雯 彭;牧 王

Optics Letters

2017-3-15

Generally, it is well known that the lithium-ion diffusion in olivine Li_xFePO₄ is correlated with the phase transition dominated by a domino-cascade model instead of a core-shell model. Based on the experiment result, we firstly found that the linear Warburg region of electrochemical impedance spectra should tilt with a small angle of 30° for the domino-cascade model, while the core-shell model should correspond to a traditional angle of about 45°. Considering that the measured Warburg impedance varies along the charge and discharge processes, we firstly proposed a hybrid phase-transition model as a combination of the domino-cascade model and the core-shell model to describe the olivine Li_xFePO₄. And this hybrid model was possibly attributed to both the strong anisotropy in the bulk of olivine Li_xFePO₄ and the different properties between the lithiated and delithiated phases. Potentially, this micro-mechanism could be extended to some other two-phase electrode active materials in lithium ion batteries.

De Li;Tao Zhang;Xizheng Liu;Ping He;茹雯 彭;牧 王;民 韩;豪慎 周

Journal of Power Sources

2013

Controlling the polarization state, the transmission direction, the amplitude and the phase of light in a very limited space is essential for the development of on-chip photonics. Over the past decades, numerous sub-wavelength metallic microstructures have been proposed and fabricated to fulfill these demands. In this article, we review our efforts in achieving negative refractive index, controlling the polarization state, and tuning the amplitude of light with two-dimensional (2D) and three-dimensional (3D) microstructures. We designed an assembly of stacked metallic U-shaped resonators that allow achieving negative refraction for pure magnetic and electric responses respectively at the same frequency by selecting the polarization of incident light. Based on this, we tune the permittivity and permeability of the structure, and achieve negative refractive index. Further, by control the excitation and radiation of surface electric current on a number of 2D and 3D asymmetric metallic metastructures, we are able to control the polarization state of light. It is also demonstrated that with a stereostructured metal film, the whole metal surfaces can be used to construct either polarization-sensitive or polarization-insensitive prefect absorbers, with the advantage of efficient heat dissipation and electric conductivity. Our practice shows that metamaterials, including metasurface, indeed help to master light in nanoscale, and are promising in the development of new generation of photonics.

Xiang Xiong;Shang Chi Jiang;Yuan Sheng Hu;Yu Hui Hu;Zheng Han Wang;茹雯 彭;牧 王

Annals of Physics

2015-7-1

In this work, we investigate electronic band structures and transport properties in dimerlike graphene superlattices (DGSLs), where the modulated potentials of square barrier A and well B on graphene are arranged as S(m) = (AB)^m(BA)^m. Here m is the repeated number of units. It is found that the mirror symmetry of the potential distribution on graphene can induce extra Dirac points (DPs), which originates from the dimerlike positional correlations in the system. The induced DPs, which are exactly located at the energy corresponding to zero averaged wave number, do not exist in the periodic graphene superlattices of (AB)^m. The number and the position of DPs in the zero averaged wave number gap of DGSL can be manipulated. Correspondingly, multiple perfect transmissions are observed at the resonant modes. Moreover, the conductance for DGSL presents extra resonant peaks accompanying with the emergence of the induced DPs. The investigations may have potential applications in graphene-based electronic devices.

Rui Li Zhang;Han Tian Gao;Yu Zhou;Ren Hao Fan;Dong Xiang Qi;茹雯 彭;Run Sheng Huang;牧 王

Applied Physics Letters

2013-9-16

In this work, we present an omnidirectional perfect transmission in the photonic band gap of a metamaterial, where positive-index and active negative-index materials are randomly stacked. Due to mismatched impedance, a photonic band gap appears when the metamaterial possesses zero averaged refractive index. By introducing the matched impedance at the expected frequency, a complete tunneling is achieved in the photonic band gap. This kind of transparency is robust against not only incident angles, optical polarization but system disorder as well. The finding is expected to achieve potential applications in optoelectronic devices.

Wei Hua Sun;Ye Lu;茹雯 彭;Lu Shuai Cao;De Li;Xin Wu;牧 王

Journal of Applied Physics

2009

Regular arrays of copper wires formed by template-assisted electrodeposition are discussed. Langmuir-Blodgett (LB) films are used for the purpose. It is shown that the width of the wires is homogeneous and both the width and the separation of the wires can be tuned by the template, across a range of 100 nm to more than 1 μm. Results show that the periodicity of the pattern can be determined by the transfer speed, whereas the ratio of the width of the stripe to the width of the channel depended on the surface density of the Langmuir film during the transfer.

Mingzhe Zhang;Steven Lenhert;牧 王;力峰 迟;Nan Lu;Harald Fuchs;Naiben Ming

Advanced Materials

2004-3-5

We demonstrate in this letter that electromagnetic waves passing through the subwavelength apertures on a silver film interfere with each other in the airgap behind the apertures. Depending on the width of the airgap, either constructive or destructive interference occurs. It is shown that constructive interference enhances the extraordinary optical transmission and evidently improves the quality factor, whereas destructive interference weakens the extraordinary optical transmission. We suggest that our results provide a unique approach to construct plasmonic structures and devices.

峰 高;De Li;茹雯 彭;靖 胡;Kuang Wei;前进 汪;Y. Y. Zhu;牧 王

Applied Physics Letters

2009

The self-assembly of iron dots on the insulating surface of NaCl(001) is investigated experimentally and theoretically. Under proper growth conditions, nanometer-scale magnetic iron dots with remarkably narrow size distributions can be achieved in the absence of a wetting layer. Furthermore, both the vertical and lateral sizes of the dots can be tuned with the iron dosage without introducing apparent size broadening, even though the clustering is clearly in the strong coarsening regime. These observations are interpreted using a phenomenological mean-field theory, in which a coverage-dependent optimal dot size is selected by strain-mediated dot-dot interactions.

Zheng Gai;Biao Wu;J. P. Pierce;G. A. Farnan;大军 舒;牧 王;Zhenyu Zhang;Jian Shen

Physical Review Letters

2002

In this letter, we have demonstrated that serrated metal gratings, which introduce gradient coatings, can give rise to broadband transmission enhancement of acoustic waves. Here, we have experimentally and theoretically studied the acoustic transmission properties of metal gratings with or without serrated boundaries. The average transmission is obviously enhanced for serrated metal gratings within a wide frequency range, while the Fabry-Perot resonance is significantly suppressed. An effective medium hypothesis with varying acoustic impedance is proposed to analyze the mechanism, which was verified through comparison with finite-element simulation. The serrated boundary supplies gradient mass distribution and gradient normal acoustic impedance, which could efficiently reduce the boundary reflection. Further, by increasing the region of the serrated boundary, we present a broadband high-transmission grating for wide range of incident angle. Our results may have potential applications to broadband acoustic imaging, acoustic sensing, and acoustic devices.

Dong Xiang Qi;Yu Qiang Deng;Di Hu Xu;Ren Hao Fan;茹雯 彭;Ze Guo Chen;明辉 卢;X. R. Huang;牧 王

Applied Physics Letters

2015-1-5

We present the structural fabrication and the optical transmission of dielectric multilayer films with a defect both theoretically and experimentally. With the transfer-matrix method, the transmission of electromagnetic waves through the multilayer can be theoretically analyzed. It is shown that a defect layer in the structure can induce the localized mode that is shown as the transmission peak in the photonic band gap (PBG). Both the intensity and the quality factor of the peak definitely change with adjusting the position of the defect in the multilayer. Further, the number of transmission peaks in the PBG can be tuned by changing the thickness of the defect layer. In the experiment, a series of TiO2/SiO2 multilayer films with the defect layer HfO2 have been fabricated using the electron-gun evaporation technique. Optical measurements are in good agreement with theoretical predictions. The investigation achieves the possible application to the wavelength division multiplexing system.

Z. Wang;茹雯 彭;F. Qiu;Z. H. Tang;X. F. Hu;X. Q. Huang;牧 王;A. Hu;S. S. Jiang;D. Feng

Journal of Crystal Growth

2005-2-15