Spatial dispersion and energy in strong chiral medium

Since the discovery of backward-wave materials, people have tried to realize strong chiral medium, which is traditionally thought impossible mainly for the reason of energy and spatial dispersion. We compare the two most popular descriptions of chiral medium. After analyzing several possible reasons for the traditional restriction, we show that strong chirality parameter leads to positive energy without any frequency-band limitation in the weak spatial dispersion. Moreover, strong chirality does not result in a strong spatial dispersion, which occurs only around the traditional limit point. For strong spatial dispersion where higher-order terms of spatial dispersion need to be considered, the energy conversation is also valid. Finally, we show that strong chirality need to be realized from the conjugated type of spatial dispersion.Comment: 6 pages, 2 figure

Negative reflections of electromagnetic waves in chiral media

We investigate the reflection properties of electromagnetic/optical waves in isotropic chiral media. When the chiral parameter is strong enough, we show that an unusual \emph{negative reflection} occurs at the interface of the chiral medium and a perfectly conducting plane, where the incident wave and one of reflected eigenwaves lie in the same side of the boundary normal. Using such a property, we further demonstrate that such a conducting plane can be used for focusing in the strong chiral medium. The related equations under paraxial optics approximation are deduced. In a special case of chiral medium, the chiral nihility, one of the bi-reflections disappears and only single reflected eigenwave exists, which goes exactly opposite to the incident wave. Hence the incident and reflected electric fields will cancel each other to yield a zero total electric field. In another word, any electromagnetic waves entering the chiral nihility with perfectly conducting plane will disappear.Comment: 5 pages, 5 figure

Fast and accurate simulations of transmission-line metamaterials using transmission-matrix method

Recently, two-dimensional (2D) periodically L and C loaded transmission-line (TL) networks have been applied to represent metamaterials. The commercial Agilent's Advanced Design System (ADS) is a commonly-used tool to simulate the TL metamaterials. However, it takes a lot of time to set up the TL network and perform numerical simulations using ADS, making the metamaterial analysis inefficient, especially for large-scale TL networks. In this paper, we propose transmission-matrix method (TMM) to simulate and analyze the TL-network metamaterials efficiently. Compared to the ADS commercial software, TMM provides nearly the same simulation results for the same networks. However, the model-process and simulation time has been greatly reduced. The proposed TMM can serve as an efficient tool to study the TL-network metamaterials.Comment: 15 pages, 13 figure

Super-resolution image transfer by a vortex-like metamaterial

We propose a vortex-like metamaterial device that is capable of transferring image along a spiral route without losing subwavelength information of the image. The super-resolution image can be guided and magnified at the same time with one single design. Our design may provide insights in manipulating super-resolution image in a more flexible manner. Examples are given and illustrated with numerical simulations.Comment: 7 pages, 6 figure

Illusion Media: Generating Virtual Objects Using Realizable Metamaterials

We propose a class of optical transformation media, illusion media, which render the enclosed object invisible and generate one or more virtual objects as desired. We apply the proposed media to design a microwave device, which transforms an actual object into two virtual objects. Such an illusion device exhibits unusual electromagnetic behavior as verified by full-wave simulations. Different from the published illusion devices which are composed of left-handed materials with simultaneously negative permittivity and permeability, the proposed illusion media have finite and positive permittivity and permeability. Hence the designed device could be realizable using artificial metamaterials.Comment: 9 pages, 4 figures, published in Appl. Phys. Lett