Peijun Yao
Chinese Academy of Sciences
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Publication
Featured researches published by Peijun Yao.
Physical Review B | 2007
Huanyang Chen; Zixian Liang; Peijun Yao; Xunya Jiang; Hongru Ma; Che Ting Chan
Using the idea of transformation medium, a cloak can be designed to make a domain invisible for one target frequency. In this article, we examine the possibility to extend the bandwidth of such a cloak. We obtained a constraint of the band width, which is summarized as a simple inequality that states that limits the bandwidth of operation. The constraint originates from causality requirements. We suggest a simple strategy that can get around the constraint.
Applied Physics Letters | 2007
Deyin Zhao; Jie Zhang; Peijun Yao; Xunya Jiang; Xiyao Chen
The authors design a photonic crystal Mach-Zehnder interferometer by utilizing the self-collimated beams and the bending and splitting mechanisms of line defects. Using this interferometer, they investigate the phase shift of the reflected and transmitted self-collimated beams over the line defects. In addition, on the basis of the intensity-asymmetric unidirectional-output design, they demonstrate that such interferometers can function as an intensity detector or an ultrafast optical switch when the material of photonic crystal is nonlinear.
Applied Physics Letters | 2008
Zixian Liang; Peijun Yao; Xiaowei Sun; Xunya Jiang
We investigate the dynamical process of dispersive cloak by finite-difference time-domain numerical experiments. We find that there is a strong scattering process before achieving the stable state and its time length can be tuned by the dispersive strength. Poynting-vector directions show that the stable cloaking state is constructed locally while an intensity front sweeps through the cloak. Deeper studies demonstrate that the group velocity tangent component Vgθ is the dominant element in the process. This study is helpful not only for clear physical pictures but also for designing better cloaks to defend pulsive radars.
Applied Physics Letters | 2008
Peijun Yao; Zixian Liang; Xunya Jiang
Based on causality, the limitation of the electromagnetic cloak with dispersive material is investigated in this letter. The results show that perfect invisibility cannot be achieved because of the dilemma that either the group velocity Vg diverges or a strong absorption is imposed on the cloaking material. It is an intrinsic conflict which originates from the demand of causality. However, the total cross section can really be reduced through the approach of coordinate transformation. A simulation of finite-difference time-domain method is performed to validate our analysis.
Applied Physics Letters | 2006
Xunya Jiang; Wenda Han; Peijun Yao; Wei Li
From numerical experiments, a dramatic observation of temporal-coherence gain of the image field is made for the negative-index superlens with a random quasimonochromatic source, even when there is almost no reflection and no frequency filtering effects. A single-parameter theory which can explain the phenomenon quantitatively is constructed based on the physical picture that signals propagating through the negative-index material on different paths have a different retardation time. The theoretical results agree excellently with the numerical ones.
Applied Physics Letters | 2008
Chuanhong Zhou; Qian Gong; Peijun Yao; Deyin Zhao; Xunya Jiang
We report the bulletlike propagation of light pulse in a particularly designed two-dimensional (2D) photonic crystal. Unlike traditional light bullet supported by nonlinear materials, this bulletlike propagation is achieved only by 2D photonic crystal, where the diffraction and the group velocity dispersion of a light pulse are eliminated naturally by combining two distinct properties of photonic crystal, i.e., self-collimation and zero group velocity dispersion. Moreover, we studied the influence of third order dispersion on the propagation of light bullet and found that it can be greatly suppressed by an improved structure of photonic crystal.
Archive | 2010
Xunya Jiang; Zheng Liu; Zixian Liang; Peijun Yao; Xulin Lin; Huanyang Chen
We investigate the dynamical characteristics of metamaterial systems, such as the temporal coherence gain of superlens, the causality limitation on the ideal cloaking systems, the relaxation process and essential elements in the dispersive cloaking systems, and extending the working frequency range of cloaking systems. The point of our study is the physical dispersive properties of meta-materials, which are well known to be intrinsically strongly dispersive. With physical dispersion, new physical pictures could be obtained for the waves propagating inside metamaterial, such as the “group retarded time” for waves inside superlens and cloak, the causality limitation on real metamaterial systems, and the essential elements for design optimization. So we believe the dynamical study of meta-materials will be an important direction for further research. All theoretical derivations and conclusions are demonstrated by powerful finite-difference time-domain simulations.
Optics Express | 2006
Peijun Yao; Wei Li; Songlin Feng; Xunya Jiang
Archive | 2008
Xunya Jiang; Deyin Zhao; Xiyao Chen; Jie Zhang; Peijun Yao
Physical Review B | 2007
Peijun Yao; Chuanhong Zhou; Lina Shi; Xunya Jiang