Transformation optics

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

Left-handed metamaterials based on a leaf-shaped configuration

Abstract: Based upon the bionics principle, we present the design of a metal-dielectric-metal sandwiched leaf-shaped metamaterial, and the numerical simulation and experiment have confirmed an obvious left-handed transmission peak by this structure. The retrieved effective permittivity, permeability, and refractive index are all negative around the frequency of the resonant peak, and the planar lens focusing experiment has further confirmed its left-handed features. The results in this paper can be used to explain the resonance mechanism of the left-handed metamaterialsfabricated by means of the nano-self-assembly approach, and thus may greatly promote the development of optical metamaterials.

Near-Infrared Invisibility Cloak Engineered With Two-Phase Metal-Dielectric Composites

Abstract: An electromagnetic cloaking device made with composite materials and operating in the range of near-infrared light is presented. The invisibility cloak is designed with transformation optics and consists of 15 concentric rings of different anisotropic two-phase metal-dielectric composites. The anisotropic material parameters of the nanocomposites are expressed with the Maxwell-Garnett mixing rule. The finite element simulation of the concealment produced by the multilayer nanocomposite is discussed. The geometry of the inclusions and the material parameters of the composites are determined with differential evolution-based optimization.

Radial anisotropy from a geometric viewpoint: Topological singularity and effective medium realization

Abstract: The correspondence between curved space-times and inhomogeneous dielectrics has been recently explored as a powerful tool to understand and manipulate novel electromagnetic behaviors in complex media. Here, we present a theoretical investigation on the optics of radially anisotropic material from a geometric viewpoint. Within the framework of transformation optics, we show that the optical medium with radial anisotropy is equivalent to a disclination geometry, which is a line topological defect carrying singular curvature. By introducing a geometric parameter characterizing the global topology of the disclination space, we systematically analyze the effective geometry and the topological charge associated with two typical radial anisotropies consisting of concentric multilayers or symmetric slices in both elliptical and hyperbolical regions. It is shown that elliptical and hyperbolic radial anisotropies give rise to optical Riemannian and pseudo-Riemannian geometries, respectively. Moreover, we investigate the wave optics as well as the semiclassical ray dynamics of light in the metamaterials at optical wavelengths from the perspective of coordinate transformation. It is found that the singularity acts on the light with an attractive or repulsive inverse cube force, depending on the topological charge. Our theory provides a simple and unified framework for light in optical media of various radial anisotropies and may shed new light on the dynamics of classical and quantum waves in topological nontrivial space.

Ray-optical transformation optics with ideal thin lenses makes omnidirectional lenses.

Abstract: We present the theory of ray-optical transformation optics (RTO) with ideal thin lenses and show that ideal-thin-lens RTO devices are omnidirectional lenses. Key to designing such devices are two theorems, the loop-imaging theorem, and the edge-imaging theorem, which ensure that the interior physical space is distorted in the same way for all viewing directions. We discuss the possibility of realising such devices using lens holograms or Fresnel lenses, as both are in principle capable of changing the directions of rays incident from a specific point precisely like an ideal thin lens, thereby enabling macroscopic and broad-band RTO devices that work for at least one viewing position. Even when restricted in this way, our work opens up new possibilities in ray optics. Our devices have the potential to form the basis of new microscope objectives, virtual-reality headsets, and medical spectacles.