Analysis in temporal regime of dispersive invisible structures designed from transformation optics

Gralak, Boris; Arismendi, G.; Avril, B.; Diatta, André; Guenneau, Sébastien

doi:10.1103/physrevb.93.121114

Cited by 9 publications

(7 citation statements)

References 28 publications

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“…[ 3,20,21,23–25 ] Cloak invisibility to short pulses has been rarely tested, [ 24,26–28 ] since these inhomogeneous, magnetic, and anisotropic metamaterial structures are subject to inherent frequency dispersion, which is likely to distort the pulse both in space and time and makes its reconstruction challenging. [ 29,30 ] Broadband cloaking has been realized in various systems, including acoustic, [ 25 ] elastic, [ 20,21 ] and water waves. [ 6 ] But achieving broad spectral range operation does not guarantee that a pulse propagating through the transformed medium will remain undistorted.…”

Section: Introductionmentioning

confidence: 99%

Pulse Dynamics of Flexural Waves in Transformed Plates

Tang

Guenneau

et al. 2021

Adv Funct Materials

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Coordinate‐transformation‐inspired optical devices have been mostly examined in the continuous‐wave regime: the performance of an invisibility cloak, which has been demonstrated for monochromatic excitation, is likely to deteriorate for short pulses. Here, pulse dynamics of flexural waves propagating in transformed plates is investigated. A practical realization of a waveshifter and a rotator for flexural waves based on the coordinate transformation method is proposed. Time‐resolved measurements reveal how the waveshifter deviates a short pulse from its initial trajectory, with no reflection at the bend and no spatial and temporal distortion of the pulse. Extending the strategy to cylindrical coordinates, a wave rotator is designed. It is demonstrated experimentally how a pulsed plane wave is twisted inside the rotator, while its wavefront is recovered behind the rotator and the pulse shape is preserved, with no extra time delay. The realization of the dynamical mirage effect is proposed, where an obstacle appears oriented in a deceptive direction.

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Section: Introductionmentioning

confidence: 99%

Pulse Dynamics of Flexural Waves in Transformed Plates

Tang

Guenneau

et al. 2021

Adv Funct Materials

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“…However, experimental investigations of cloaking have been mostly restricted to continuous-wave (CW) excitation [3,21,15,16,22,23]. Cloak invisibility to short pulses has been rarely tested [24,22], since these inhomogeneous, magnetic, and anisotropic metamaterial structures are subject to inherent frequency dispersion, which inevitably distorts the pulse both in space and time and makes its reconstruction challenging [25,26]. Broadband cloaking has been realized in various systems, including acoustic [23], elastic [15,16], and water waves [6].…”

Section: Introductionmentioning

confidence: 99%

Pulse dynamics of flexural waves in transformed plates

Tang,

Xu,

Guenneau

et al. 2020

Preprint

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Coordinate-transformation-inspired optical devices have been mostly examined in the continuous-wave regime: the performance of an invisibility cloak, which has been demonstrated for monochromatic excitation, would inevitably deteriorate for short pulses. Here we investigate pulse dynamics of flexural waves propagating in transformed plates. We propose a practical realization of a waveshifter and a rotator for flexural waves based on the coordinate transformation method. Time-resolved measurements reveal how the waveshifter deviates a short pulse from its initial trajectory, with no reflection at the bend and no spatial and temporal distortion of the pulse. An invisible cloak for flexural waves is proposed based on this elementary transformed device. Extending our strategy to cylindrical coordinates, we design a perfectly invisible wave rotator. We demonstrate experimentally how a pulsed plane wave is twisted inside the rotator, while its wavefront is recovered behind the rotator and the pulse shape is preserved, with no extra time delay. We propose the realization of the dynamical mirage effect, where an obstacle is seen to be oriented in a deceptive direction.

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“…More recently, the introduction of negative index materials [17][18][19][20], metamaterials and transformation optics [21][22][23] caused an additional interest for the dispersion phenomenon [17]. Hence, the effect of dispersion has been recently investigated in the cases of the flat lens [24][25][26][27][28] and invisibility systems [29].…”

Section: Introductionmentioning

confidence: 99%

Modal analysis of wave propagation in dispersive media

Abdelrahman

Gralak

2018

Phys. Rev. A

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Surveys on wave propagation in dispersive media have been limited since the pioneering work of Sommerfeld [Ann. Phys. 349, 177 (1914)] by the presence of branches in the integral expression of the wave function. In this article, a method is proposed to eliminate these critical branches and hence to establish a modal expansion of the time-dependent wave function. The different components of the transient waves are physically interpreted as the contributions of distinct sets of modes and characterized accordingly. Then, the modal expansion is used to derive a modified analytical expression of the Sommerfeld precursor improving significantly the description of the amplitude and the oscillating period up to the arrival of the Brillouin precursor. The proposed method and results apply to all waves governed by the Helmholtz equations.Comment: 10 pages, 9 figure

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Analysis in temporal regime of dispersive invisible structures designed from transformation optics

Cited by 9 publications

References 28 publications

Pulse Dynamics of Flexural Waves in Transformed Plates

Pulse Dynamics of Flexural Waves in Transformed Plates

Pulse dynamics of flexural waves in transformed plates

Modal analysis of wave propagation in dispersive media

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