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Coordinate transformations make perfect invisibility cloaks with arbitrary shape
KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.ORCID iD: 0000-0002-3368-9786
KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
2008 (English)In: New Journal of Physics, ISSN 1367-2630, Vol. 10Article in journal (Refereed) Published
Abstract [en]

By investigating wave properties at cloak boundaries, invisibility cloaks with arbitrary shape constructed by general coordinate transformations are confirmed to be perfectly invisible to the external incident wave. The differences between line transformed cloaks and point transformed cloaks are discussed. The fields in the cloak medium are found analytically to be related to the fields in the original space via coordinate transformation functions. At the exterior boundary of the cloak, it is shown that no reflection is excited even though the permittivity and permeability do not always have a perfectly matched layer form, whereas at the inner boundary, no reflection is excited either, and in particular no field can penetrate into the cloaked region. However, for the inner boundary of any line transformed cloak, the permittivity and permeability in a specific tangential direction are always required to be infinitely large. Furthermore, the field discontinuity at the inner boundary always exists; the surface current is induced to make this discontinuity self-consistent. A point transformed cloak does not experience such problems. The tangential fields at the inner boundary are all zero, implying that no field discontinuity exists.

Place, publisher, year, edition, pages
2008. Vol. 10
Keyword [en]
frequencies, devices
URN: urn:nbn:se:kth:diva-17528DOI: 10.1088/1367-2630/10/4/043040ISI: 000255793300001ScopusID: 2-s2.0-46449091497OAI: diva2:335572
QC 20100525Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2010-11-02Bibliographically approved
In thesis
1. Manipulation of Light with Transformation Optics
Open this publication in new window or tab >>Manipulation of Light with Transformation Optics
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Transformation optics, a recently booming area, provides people a new approach to design optical devices for manipulating light. With transformation optics, a lot of novel optical devices are proposed, such as invisibility cloaks, optical wormholes, optical black holes, illusion devices. The present thesis is devoted to investigate transformation optics for manipulating light.

Firstly, an introduction to transformation optics is given. This part includes: (1) introducing differential geometry as the mathematical preparation; (2) expressing Maxwell’s equations in an arbitrary coordinate system and introducing the concept of transformation media as the foundation stone of transformation optics; (3) discussing light from the geometry perspective as the essence of transformation optics; (4) showing how to use transformation optics to design optical devices.

For our works on invisibility cloaks, we analyze the properties of arbitrary shaped invisibility cloaks, and confirm their invisibility abilities. The geometrical perturbations to cylindrical and spherical shaped cloaks are analyzed in detail. We show that the cylindrical cloak is more sensitive to the perturbation than a spherical cloak. By imposing a PEC (PMC) layer at the interior boundary of the cylindrical cloak shell for TM (TE) wave, the sensitivity can be reduced dramatically. A simplified non-magnetic cylindrical cloak is also designed. We show that the dominant zeroth order scattering term can be eliminated by employing an air gap between the cloak and the cloaked region.

We propose a compensated bilayer by a folding coordinate transformation based on transformation optics. It is pointed out that complementary media, perfect negative index lens and perfect bilayer lens made of indefinite media are well unified under the scope of the transformed compensated bilayer. We demonstrate the applications of the compensated bilayer, such as perfect imaging and optical illusion. Arbitrary shaped compensated bilayers are also analyzed.

Nihility media known as the media with ε =μ= 0, are generalized from transformation optics as transformation media derived from volumeless geometrical elements. The practical constructions of nihility media by metamaterials are discussed. The eigen fields in the nihility media are derived. The interactions between an external incident wave and a slab of nihility media in the free space background are analyzed.

A new type of transformation media called α media is proposed for manipulating light. Light rays in the α media have a simple displacement or rotation relationship with those in another media (seed media). Such relationship is named α relationship. The α media can be designed and simplified to a certain class of diagonal anisotropic media, which are related to certain isotropic media by the α relationship. Several optical devices based on the α transformation media are designed. Invisibility cloaks obtained from the coordinate transformation approach are revisited from a different perspective.

Place, publisher, year, edition, pages
Stockholm: KTH, 2010. xiii, 99 p.
Trita-ICT/MAP AVH, ISSN 1653-7610 ; 2010:09
transformation optics, Maxwell’s equations, invisibility cloaks, compensated bilayer, perfect imaging, optical illusion, nihility media, α media
National Category
Atom and Molecular Physics and Optics
urn:nbn:se:kth:diva-25849 (URN)
Public defence
2010-11-22, Sal / Hall C1, KTH-Electrum, Isafjordsgatan 26, Kista, 10:00 (English)
QC 20101102Available from: 2010-11-02 Created: 2010-11-02 Last updated: 2012-03-28Bibliographically approved

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Yan, WeiYan, MinRuan, ZhichaoQiu, Min
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