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Transforming space with non-Hermitian dielectrics.
TL;DR: In this article, the authors show how non-conformal distortions of optical space are intimately connected to the complex refractive index distribution of an isotropic non-Hermitian medium.
Abstract: Coordinate transformations are a versatile tool to mould the flow of light, enabling a host of astonishing phenomena such as optical cloaking with metamaterials. Moving away from the usual restriction that links isotropic materials with conformal transformations, we show how non-conformal distortions of optical space are intimately connected to the complex refractive index distribution of an isotropic non-Hermitian medium. Remarkably, this insight can be used to circumvent the material requirement of working with refractive indices below unity, which limits the applications of transformation optics. We apply our approach to design a two-dimensional broadband dielectric cloak, which relies on non-conformal coordinate transformations to tailor the non-Hermitian refractive index profile around a cloaked object. Our insights bridge the fields of two-dimensional transformation optics and non-Hermitian photonics.
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TL;DR: A brief review of the fundamental physics, novel properties and practical applications of topological photonic states (TPSs) based on GPCs can be found in this paper , where the authors provide a useful guidance and motivation for interested scientists and engineers working in related scientific and technological areas.
Abstract:
Topological photonic states (TPSs) as a new type of waveguide state with one-way transport property can resist backscattering and are impervious to defects, disorders and metallic obstacles. Gyromagnetic photonic crystal (GPC) is the first artificial microstructure to implement TPSs, and it is also one of the most important platforms for generating truly one-way TPSs and exploring their novel physical properties, transport phenomena and advanced applications. Herein, we present a brief review of the fundamental physics, novel properties and practical applications of TPSs based on GPCs. We first examine chiral one-way edge states existing in uniformly magnetized GPCs of ordered and disordered lattices, antichiral one-way edge states in cross magnetized GPCs, and robust one-way bulk states in heterogeneously magnetized GPCs. Then, we discuss the strongly coupling effect between two co-propagating (or counter-propagating) TPSs and the resulting physical phenomena and device applications. Finally, we analyze the key issues and prospect the future development trends for TPSs in GPCs. The purpose of this brief review is to provide an overview of the main features of TPSs in GPC systems and offer a useful guidance and motivation for interested scientists and engineers working in related scientific and technological areas.
3 citations
TL;DR: A brief review of the fundamental physics, novel properties, and practical applications of topological photonic states (TPSs) based on GPCs can be found in this paper .
Abstract: Topological photonic states (TPSs) as a new type of waveguide state with one-way transport property can resist backscattering and are impervious to defects, disorders and metallic obstacles. Gyromagnetic photonic crystal (GPC) is the first artificial microstructure to implement TPSs, and it is also one of the most important platforms for generating truly one-way TPSs and exploring their novel physical properties, transport phenomena, and advanced applications. Herein, we present a brief review of the fundamental physics, novel properties, and practical applications of TPSs based on GPCs. We first examine chiral one-way edge states existing in uniformly magnetized GPCs of ordered and disordered lattices, antichiral one-way edge states in cross magnetized GPCs, and robust one-way bulk states in heterogeneously magnetized GPCs. Then, we discuss the strongly coupling effect between two co-propagating (or counter-propagating) TPSs and the resulting physical phenomena and device applications. Finally, we analyze the key issues and prospect the future development trends for TPSs in GPCs. The purpose of this brief review is to provide an overview of the main features of TPSs in GPC systems and offer a useful guidance and motivation for interested scientists and engineers working in related scientific and technological areas.
3 citations
TL;DR: In this paper , the authors discuss the perfect absorption, exceptional points and surfaces waves of non-Hermitian electromagnetic metasurfaces, and point out the challenges and potentials of this field.
Abstract: Electromagnetic metasurfaces, as a class of planar electromagnetic materials consisting of single-layer or multilayer subwavelength artificial micro-structures, can efficiently control the polarization, amplitude and phase of electromagnetic waves in the subwavelength scale. However, confining electromagnetic waves to deep-subwavelength scale generally comes at the cost of a large loss, such as such as radiation loss, Ohmic loss. Interestingly, non-Hermitian physics provides us a new way to transform the disadvantage of loss to a new degree of freedom in metasurface design, paving the way to expanding the functionalities of metasurfaces. In recent years, the extraordinary effects in the non-Hermitian electromagnetic metasurfaces have attracted a lot of attention. In this review, we discuss the perfect absorption, exceptional points and surfaces waves of non-Hermitian electromagnetic metasurfaces, and point out the challenges and potentials of this field.
2 citations
06 Oct 2022
TL;DR: In this paper , the authors developed a transformation theory for controlling temperature fields in conduction and advection, and designed three metamaterials to control thermal waves with cloaking, concentrating, and rotating functions.
Abstract: Abstract In this chapter, we develop a transformation theory for controlling wavelike temperature fields (called thermal waves herein) in conduction and advection. We first unify these two basic heat transfer modes by coining a complex thermal conductivity whose real and imaginary parts are related to conduction and advection. Consequently, the conduction-advection process supporting thermal waves is described by a complex conduction equation, thus called complex thermotics. We then propose the principle for transforming complex thermal conductivities. We further design three metamaterials to control thermal waves with cloaking, concentrating, and rotating functions. Experimental suggestions are also provided based on porous media.
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