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450 results on '"Dong, Jian-Wen"'

160. Unusual Optical Properties of Helical Metallic Photonic Crystals and Chiral Channels in Dielectric Photonic Crystals

Author

Li, Hongqiang, Dong, Jian Wen, Chan, Che Ting, Li, Hongqiang, Dong, Jian Wen, and Chan, Che Ting

Abstract

In this chapter, we will show that a photonic crystal comprising an array of subwavelength metallic helices has a unique photonic dispersion that allows for the realization of negative refraction for frequencies both above and below the polarization gap for electromagnetic waves propagating along the helical axis. The helical photonic crystal can also serve as a broadband wave plate for waves propagating perpendicular to the helical axis of the metallic photonic crystal. In addition, we show that robust transport of light can be achieved using chiral photonic guided modes in a channel of a dielectric photonic crystal. The light transport is immune to the scattering of isotropic homogenous impurities and the phenomenon bears some phenomenological similarity to robust transport of electrons in topological insulators, although the mechanism is not the same. In particular, the system is time-reversal invariant and the robust one-way transport does not require an external field, which is distinct from the previous strategies employing two-dimensional magnetic photonic crystals with explicit time reversal breaking by an external field.

Published
2014

165. On the Time Evolution of the Cloaking Effect of a Metamaterial Slab

Author

Xiao, Meng, Huang, Xueqin, Dong, Jian-Wen, Chan, Che Ting, Xiao, Meng, Huang, Xueqin, Dong, Jian-Wen, and Chan, Che Ting

Abstract

We investigated the time evolution of the cloaking behavior of a small particle placed in front of a meta-material slab with epsilon = mu = -1 + i delta. We found that the dipole excitation would be suppressed in the long time limit. While on the way to being cloaked, the excitation will exhibit oscillatory behavior as the result of the interference between particle-slab resonances and high density-of-states surface modes. (C) 2012 Optical Society of America

Published
2012

166. Metamaterial Slab as a Lens, a Cloak, or an Intermediate

Author

Dong, Jian-Wen, Zheng, Huihuo, Lai, Yun, Wang, He-Zhou, Chan, Che Ting, Dong, Jian-Wen, Zheng, Huihuo, Lai, Yun, Wang, He-Zhou, and Chan, Che Ting

Abstract

We show that a metamaterial slab with arbitrary values of ɛ and μ behaves as a cloak at a finite frequency for a small object located sufficiently close to it due to the suppression of the object's optical excitations by enhanced reflections. Reflections due to propagating components can partially suppress the excitation, while evanescent components can cloak the object completely. In particular, a Veselago slab with ɛ=μ=−1+iδ, as well as a class of anisotropic negative refractive index slabs, can completely cloak the small object placed within a finite distance from the slab when δ→0.

Published
2011

167. Fano resonance of three-dimensional spiral photonic crystals: Paradoxical transmission and polarization gap

Author

Chen, Wen-Jie, Lee, Chi Wai Jeffrey, Dong, Jian-Wen, Qiu, Cheng-Wei, Wang, He-Zhou, Chen, Wen-Jie, Lee, Chi Wai Jeffrey, Dong, Jian-Wen, Qiu, Cheng-Wei, and Wang, He-Zhou

Abstract

Extraordinary Fano resonance with right handedness is present in a right-handed polarization gap of compound spiral photonic crystals. The structure is composed of unit cells with double helices of pi phase shift arranged in square lattice. Such a paradoxical phenomenon is derived from mode interferences between left-handed propagating modes along spiral axis and negative group velocity modes in extended Brillouin zone. By analyzing Fourier spectra and chirality of photonic eigenmodes, intrinsic mechanism is well understood by mode coupling theory. (C) 2011 American Institute of Physics.

Published
2011

177. Valley photonic crystals for control of spin and topology

Author

Dong, Jian-Wen, Chen, Xiao-Dong, Zhu, Hanyu, Wang, Yuan, and Zhang, Xiang

Abstract

Photonic crystals offer unprecedented opportunity for light manipulation and applications in optical communication and sensing. Exploration of topology in photonic crystals and metamaterials with non-zero gauge field has inspired a number of intriguing optical phenomena such as one-way transport and Weyl points. Recently, a new degree of freedom, valley, has been demonstrated in two-dimensional materials. Here, we propose a concept of valley photonic crystals with electromagnetic duality symmetry but broken inversion symmetry. We observe photonic valley Hall effect originating from valley-dependent spin-split bulk bands, even in topologically trivial photonic crystals. Valley–spin locking behaviour results in selective net spin flow inside bulk valley photonic crystals. We also show the independent control of valley and topology in a single system that has been long pursued in electronic systems, resulting in topologically-protected flat edge states. Valley photonic crystals not only offer a route towards the observation of non-trivial states, but also open the way for device applications in integrated photonics and information processing using spin-dependent transportation.

Published
2017
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186. A ZASP Missense Mutation, S196L, Leads to Cytoskeletal and Electrical Abnormalities in a Mouse Model of Cardiomyopathy

Author

Li, Zhaohui, primary, Ai, Tomohiko, additional, Samani, Kaveh, additional, Xi, Yutao, additional, Tzeng, Huei-Ping, additional, Xie, Mingxing, additional, Wu, Shan, additional, Ge, Shuping, additional, Taylor, Michael D., additional, Dong, Jian-Wen, additional, Cheng, Jie, additional, Ackerman, Michael J., additional, Kimura, Akinori, additional, Sinagra, Gianfranco, additional, Brunelli, Luca, additional, Faulkner, Georgine, additional, and Vatta, Matteo, additional

Published
2010
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198. Sensitive temperature sensor based on phase properties of photonic crystal

Author

Leng Feng-Chun, Huang Qin, Liang Wen-Yao, Wang He-Zhou, and Dong Jian-Wen

Subjects
Optics, Materials science, Linear range, business.industry, Phase (waves), General Physics and Astronomy, Temperature sensitive, Optical integration, business, Layer (electronics), Reflectivity, Highly sensitive, Photonic crystal
Abstract

It is revealed in the present paper that the reflectance around the defect mode of one-dimensional defective photonic crystal (PC) in an asymmetric structure approaches to 1, while the phase-shift depends on the number of the coupled-defect layers, i.e., the phase shift is 2π for every sub-peak of the defect mode. When the defect layer is a temperature sensitive material, very small change of temperature will cause a significant phase change. Secondly, it is demonstrated that the relationship of phase and temperature has a linear range. According to the above characteristics, a highly sensitive temperature sensor is designed based on the phase property of photonic crystal. Moreover, this principle of PC phase sensing can be extended to study other sensors, such as the two-dimensional PC, which is suitable for optical integration.

Published
2010
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200. Phase properties of photonic crystal heterostructure and its applications

Author

Chen Di-hu, Wang He-Zhou, Dong Jian-Wen, Wu Kai-Shun, and Long Xing-Teng

Subjects
Materials science, business.industry, Phase (waves), Physics::Optics, General Physics and Astronomy, NAND gate, Heterojunction, Stopband, Double heterostructure, Crystal, Optics, Logic gate, Optoelectronics, business, Photonic crystal
Abstract

It is revealed that the reflectance in the whole stop band of a heterostructure, including the defect mode, approaches 1; while the phase-shift depends on the sub-photonic crystal (PC) that faces the incident direction. For every sub-peak in the defect mode or every pass band of the sub-PC facing the incident direction, the phase shift is 2π. These properties are useful for designing optical phase devices several orders more sensitive than those using amplitude-signal. In this paper, a sensitive optical phase logic gate (NAND) is described as an example of optical phase devices. Moreover, these properties are also useful for the study of related physical phenomena.

Published
2008
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