Underwater Focusing of Sound by Umklapp Diffraction

Chaplain, Gregory J.; Cole, Nick; Hibbins, Alastair P.; Starkey, Timothy A.

doi:10.1103/physrevapplied.16.064029

Cited by 5 publications

(5 citation statements)

References 35 publications

(39 reference statements)

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“…These components experience a rotational Doppler shift in the laboratory frame. However, this intriguing observation may open some new discussions on the theory of diffraction, which is still an open and highly debated issue [27,28], not only in optics [29,30]. * * *…”

Section: Resultsmentioning

confidence: 99%

Frequency changes during the propagation of a light beam

Émile¹,

Emile-Etrillard²

2022

EPL

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The energy and therefore the frequency of electromagnetic ﬁelds are usually conserved quantities in free space propagation. However here, we observe a frequency varying optical wave in free space propagation. The light comes from the Arago spot and this change of frequency is based on the rotational Doppler eﬀect. More precisely, the light diﬀracted by a two-dimensional asymmetric object carries orbital angular momentum that varies with the distance. As the object rotates, the frequency of the diﬀracted light experiences diﬀerent rotational Doppler shifts along propagation. It varies in a discrete quantized manner as it propagates and can be adjusted, without violation of the conservation of energy. Since this phenomenon is deeply rooted in the diﬀraction process, it shines some new light in this still open issue.

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Section: Resultsmentioning

confidence: 99%

Frequency changes during the propagation of a light beam

Émile¹,

Emile-Etrillard²

2022

EPL

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“…The sign of the localized in-plane wavevector, k||, is reversed, resulting in a ‘flipping’ of its direction in the plane parallel to the interface. It is for this reason that this mechanism has been termed Umklapp diffraction in recent acoustic/elastic analogues [40,41] and has been adopted to describe general band-folding effects [42].…”

Section: Designmentioning

confidence: 99%

“…Figure 3 a shows a comparison of the experimental and numerical results in the near field; the angle of the diffracted beams clearly matches those predicted from the one-dimensional periodic dispersion curves. The overlap of these beams has been considered a focus of power in the acoustic analogue [41]. The far-field beam profile is obtained numerically from the simulated data by using the Stratton–Chu formula [45].…”

Section: Multi-scale Bullseye Antennasmentioning

confidence: 99%

Multi-scale bullseye antennas

Chaplain

Hooper

Starkey

2022

Phil. Trans. R. Soc. A.

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We design, simulate and experimentally characterize a multi-scale bullseye antenna for the broadband manipulation of microwaves. The device achieves far-field beam-forming via tailored diffraction at the interface between two concentric bullseye geometries, with near-field energy concentration resulting from the overlap of the diffracted beams. This article is part of the theme issue ‘Wave generation and transmission in multi-scale complex media and structured metamaterials (part 1)’.

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“…Periodic surface phononic crystals with corrugations [35] offer a range of interface waves, the characteristics of which are influenced by the depth of corrugation, enabling guidance or mode conversion. More recently, Umklapp diffraction has been proposed, in analogy with the purely elastic case [18], to focus underwater sound [36] through thin elastic plates submerged in water. Elastic metasurfaces consisting of graded arrays of resonators on fluid-loaded elastic plates [37] have also been used to mode-convert flexural waves into bulk acoustic waves and vice versa.…”

Section: Introductionmentioning

confidence: 99%

Elastic metasurfaces for Scholte–Stoneley wave control

Zeighami,

Quqa,

De Ponti

et al. 2024

Phil. Trans. R. Soc. A.

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In this work, we investigate the dynamics of Scholte–Stoneley waves (SSWs) travelling along elastic metasurfaces, e.g. thin resonant structures embedding mechanical oscillators, placed at the interface between solid and fluid. To this purpose, an analytical dispersion law, valid in the long-wavelength regime, is derived and used to reveal the hybridization of SSWs with the collective resonance of the mechanical oscillators and the conversion of SSWs into leaky modes within the fluid. The analytical predictions are validated through numerical simulations that include both dispersive and harmonic analysis. Our findings disclose the capabilities of elastic metasurfaces in filtering, trapping and converting SSWs along fluid–solid interfaces, thus supporting the design of novel devices for solid–fluid interaction across various engineering applications, including microfluidics. This article is part of the theme issue 'Current developments in elastic and acoustic metamaterials science (Part 1)'.

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Underwater Focusing of Sound by Umklapp Diffraction

Abstract: The version presented here may differ from the published version. If citing, you are advised to consult the published version for pagination, volume/issue and date of publication

Cited by 5 publications

References 35 publications

Frequency changes during the propagation of a light beam

Frequency changes during the propagation of a light beam

Multi-scale bullseye antennas

Elastic metasurfaces for Scholte–Stoneley wave control

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