Topic
Transformation optics
About: Transformation optics is a research topic. Over the lifetime, 2687 publications have been published within this topic receiving 102378 citations.
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TL;DR: A chiral optical negative-index metamaterial design of doubly periodic construction for the near-infrared spectrum is presented and an effective material parameter retrieval procedure is developed for general bi-isotropic meetamaterials.
Abstract: A chiral optical negative-index metamaterial design of doubly periodic construction for the near-infrared spectrum is presented. The chirality is realized by incorporating sub-wavelength planar silver-alumina-silver resonators and arranging them in a left-handed helical (i.e., stair-step) configuration as a wave propagates through the metamaterial. An effective material parameter retrieval procedure is developed for general bi-isotropic metamaterials. A numerical design example is presented and the retrieved effective material parameters exhibiting a negative index of refraction are provided.
85 citations
TL;DR: A transformation optics design approach together with an experimental demonstration that takes advantage of this dimensionality by integrating multiple, independent optical elements into a single optical Janus or metadevice.
Abstract: In Roman mythology, the god Janus was depicted with two faces, looking in opposite directions. This led to the phrase ‘‘Janus faced’’ which is mostly used for a ‘‘two-faced’’ or deceitful character of a person. Within integrated photonics a concept like Janus can provide a new class of multi-functional optical meta-elements which could be a key ingredient in achieving compact and high speed photonic systems. While therehave been great strides in the miniaturization of optical elements, such photonic integration largely consists of combining discrete components at the chip level. Here, we present a new approach of designing a single optical element that possesses simultaneously multiple distinct functions. We employ transformation optics to design the optical space and manipulate the light propagation using a metamaterial with spatially varying permittivity. Our experiment demonstrates a single optical ‘‘Janus’’ device that acts as a lens as well as a beam-shifter at the same time. The emerging field of transformation optics has provided a new design methodology allowing an unprecedented manipulation of light propagation, with the optical cloak as the most prominent example. [1,2] However, transformation optics can also be used to enhance the functionality of conventional optical elements. Traditionally, these conventional elements only involve stretching or compressing the optical space in one direction whereas the remaining dimensions in space are unaltered. For example, an optical lens can be interpreted as a result of a simple wavefront transformation that molds the flow of light in a particular direction. A lens works well in one direction whereas light propagating perpendicular to this direction is strongly perturbed. Since space can be modified in two or three dimensions simultaneously, the additional degrees of freedom provided by transformation optics can be used to spatially imprint elements into a single optical Janus or metadevice. Here, we present a transformation optics design approach together with an experimental demonstration that takes advantage of this dimensionality by integrating multiple, independent optical
85 citations
TL;DR: This work uses transformation optics (TO) combined with nanolithography to produce a planar Luneburg lens with a flat focal surface that operates at telecommunication wavelengths.
Abstract: Employing artificially structured metamaterials provides a means of circumventing the limits of conventional optical materials. Here, we use transformation optics (TO) combined with nanolithography to produce a planar Luneburg lens with a flat focal surface that operates at telecommunication wavelengths. Whereas previous infrared TO devices have been transformations of free-space, here we implement a transformation of an existing optical element to create a new device with the same optical characteristics but a user-defined geometry.
84 citations
TL;DR: Fabry-Pérot resonances in materials of extreme anisotropy are used to design various transformation optical devices that are not only easy to realize but also work well for a set of resonant frequencies (multiple frequencies).
Abstract: Transformation optics is a powerful tool to design various novel devices, such as invisibility cloak. Fantastic effects from this technique are usually accompanied with singular mappings, resulting in challenging implementations and narrow bands of working frequencies. Here in this article, Fabry-Perot resonances in materials of extreme anisotropy are used to design various transformation optical devices that are not only easy to realize but also work well for a set of resonant frequencies (multiple frequencies). As an example, a prototype of a cylindrical concentrator is fabricated for microwaves.
83 citations
TL;DR: In this article, an approach to broadband cloaking of light waves is analyzed for a simplified case of a scaling transformation for a general cylindrical coordinate system, which requires metamaterials with specifically engineered dispersion.
Abstract: An approach to broadband cloaking of light waves is analysed for a simplified case of a scaling transformation for a general cylindrical coordinate system. The proposed approach requires metamaterials with specifically engineered dispersion. The restriction on the signs of gradients in the dispersion dependencies of the dielectric permittivity and the magnetic permeability for different operational wavelengths is revealed and is shown to cause difficulties unless additional gain-assisted compensation for losses or electromagnetically induced transparency is introduced in the cloaking system.
82 citations