Transformation optics

About: Transformation optics is a research topic. Over the lifetime, 2687 publications have been published within this topic receiving 102378 citations.

Magnetic energy harvesting and concentration at a distance by transformation optics.

Abstract: Based on transformation optics, we introduce a magnetic shell with which one can harvest magnetic energy and distribute it as desired in space with unprecedented efficiency at an arbitrary scale. It allows a very large concentration of magnetic energy in a free space region, which can be used for increasing the sensitivity of magnetic sensors, and the transfer of magnetic energy from a source to a given distant point separated by empty space, with possible applications in wireless transmission of energy.

Experimental demonstration of a broadband transformation optics lens for highly directive multibeam emission

Abstract: The emerging field of transformation optics, with its powerful ability to manipulate and control electromagnetic waves, represents a promising new approach to tailor the radiation properties of antennas. However, previously reported source transformation designs have been severely limited by their narrow operating bandwidth, as well as the number and directions of radiated beams. In this paper, we design, fabricate, and characterize a new type of broadband transformation optics lens capable of converting the radiation from an embedded isotropic source into any desired number of highly directive beams pointing in arbitrary directions. We exploit the dispersive properties of the metamaterial building blocks to greatly enhance the impedance bandwidth of the embedded antenna. Moreover, the simple material parameters required by the demonstrated transformation make it amenable to the development of practical beam collimating devices that operate in both the microwave and the optical regimes.

Group theoretical description of artificial electromagnetic metamaterials

Abstract: Point group theoretical methods are used to determine the electromagnetic properties of metamaterials, based solely upon the symmetries of the underlying constituent particles. From the transformation properties of an electromagnetic (EM) basis under symmetries of the particles, it is possible to determine, (i) the EM modes of the particles, (ii) the form of constitutive relations (iii) magneto-optical response of a metamaterial or lack thereof. Based upon these methods, we predict an ideal planar artificial magnetic metamaterial, and determine the subset of point groups of which particles must belong to in order to yield an isotropic 3D magnetic response, and we show an example.

Tunable terahertz metamaterials with negative permeability

Abstract: We demonstrate experimentally and theoretically dielectric metamaterials exhibiting a tunable range of negative effective permeability in the terahertz spectral region 0.2–0.36 THz. Our structures consist of an array of intrinsically nonmagnetic rods made of an incipient ferroelectric SrTiO3 which shows a high tunable permittivity. The magnetic response and its tuning are achieved by a temperature control of the permittivity of SrTiO3, which defines the resonant confinement of the electromagnetic field within the rods.

Metamaterials: electromagnetic enhancement at zero-index transition.

Abstract: Resonant enhancement of electromagnetic waves propagating at oblique incidence in metamaterials, with dielectric permittivity and magnetic permeability linearly changing from positive to negative values, has been predicted and theoretically studied. This effect occurs for both TE and TM polarizations near the point where a refractive index changes its sign. Our model elucidates the unique features of the resonant enhancement in “positive-to-negative transition” metamaterials for a broad frequency range from microwaves to optics. © 2008 Optical Society of America OCIS codes: 160.3918, 160.2710, 260.5740.