A completely covariant approach to transformation optics

Thompson, Robert T.; Cummer, Steven A.; Frauendiener, Jörg

doi:10.1088/2040-8978/13/2/024008

Cited by 57 publications

(98 citation statements)

References 21 publications

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“…In contrast, space-time modulated media do not alter the group velocities of the forward and backward harmonics, compared to the group velocities in the unmodulated medium. Moreover, in the case of a moving (isotropic) medium, the material parameters appear bianisotropic to a static observer due to the drag effect [56][57][58]. This complexity is eliminated by Lorentz transformation to the reference frame of the moving medium, where the medium becomes static and hence again isotropic.…”

Section: Comparison With Moving Systemmentioning

confidence: 99%

Optical isolation based on space-time engineered asymmetric photonic band gaps

et al. 2017

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Nonreciprocal electromagnetic devices play a crucial role in modern microwave and optical technologies. Conventional methods for realizing such systems are incompatible with integrated circuits. With recent advances in integrated photonics, the need for efficient on-chip magnetless nonreciprocal devices has become more pressing than ever. This paper leverages space-time engineered asymmetric photonic bandgaps to generate optical isolation. It shows that a properly designed space-time modulated slab is highly reflective/transparent for opposite directions of propagation. The corresponding design is magnetless, accommodates low modulation frequencies, and can achieve very high isolation levels. An experimental proof of concept at microwave frequencies is provided.

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Section: Comparison With Moving Systemmentioning

confidence: 99%

Optical isolation based on space-time engineered asymmetric photonic band gaps

et al. 2017

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“…Using [8] where transformation optics is expressed as a geometric formulation on spacetime manifolds, an expression similar to Eq. (15) has been generated.…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…A formalism of transformation optics which also encompasses gravitational curvature has been illustrated in [7]. A technique which uses transformation between spacetime manifolds with application to cloaking is shown in [8]. Cloaks with non-conformal inner and outer boundaries have been analysed at by Li and Li [9].…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic cloaking in convex and concave media with surface modelled as a parameterised function

Sidhwa¹,

Aiyar²,

Kulkarni³

2015

Opt. Express

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Abstract:The onset of transformation optics has opened avenues for designing of a plenitude of applications related to propagation of electromagnetic waves in anisotropic media. In this paper, an algorithm is proposed using a coordinate transformation and a piecewise function for the purpose of designing a three dimensional cloak having an arbitrary geometry which could be convex or non-convex in nature. The surfaces of the cloak as well as of the body under consideration are assumed to be conformal to each other. For an arbitrary geometry, the coordinate system needed to model the surface can be a non-orthogonal system. For the purpose of verification of the algorithm, a ray tracing process is carried out for an ellipsoid as well as for a concave surface having axial symmetry. In order to solve the Hamiltonian equation for the purpose of ray tracing, the process of finding the derivatives analytically, for an arbitrary geometry as considered here, becomes very cumbersome. Here, a numerical method is described which provides a better approximation to the partial derivatives than the conventional finite difference approach based on forward differences.

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“…Transformation Design-the use of the mathematical transformation of reference materials into those interesting 'device' properties-is an area of active research interest. Investigations range all the way from the most abstract theory and conceptualizing [1][2][3][4][5][6] through to concrete theoretical proposals [1,[7][8][9][10][11][12][13] and technological implementations [14][15][16][17][18][19]. One aspiration is the 'perfect cloak', a Transformation Device (Tdevice) redirecting light, sound, or other signals so that a fixed interior (core) region is invisible and undetectable by outside observers.…”

Section: Introductionmentioning

confidence: 99%

Impedance rescaling and scattering from transformation optics devices

Kinsler

2018

J. Phys. Commun.

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I investigate the scattering properties of transformation devices as the impedance matching criteria are altered. Starting from an analysis of traditional impedance calculations, we see how to preserve the cloak's 'steering' refractive index profile whilst adjusting the 'scattering' impedance profile. Results are presented for transformation devices in a cylindrical geometry, but the lessons apply to both simpler and more complicated transformation devices. One technique used here is the use of impulsive field inputs, so that scattered fields are more easily distinguished from non-scattered fields. A two-axis continuous range of impedance profiles is shown to cover the three most important cases. This range is investigated numerically, with the summed scattering field being used as an indicator of device performance. We see that the standard 'k-medium' case where e m = gives best performance, but with different rescalings giving different levels of deterioration.

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A completely covariant approach to transformation optics

Cited by 57 publications

References 21 publications

Optical isolation based on space-time engineered asymmetric photonic band gaps

Optical isolation based on space-time engineered asymmetric photonic band gaps

Electromagnetic cloaking in convex and concave media with surface modelled as a parameterised function

Impedance rescaling and scattering from transformation optics devices

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