Communication Dans Un Congrès Année : 2024

Numerical study of a Fabry-Perot based elastic EAT system at MHz regime

Résumé

Since its first discovery in 1998 by T.W. Ebbesen[1], Extraordinary Transmission (ET) has aroused the interest of acousticians and opticians, as it offers the potential to concentrate more wave energy than geometric considerations[2], in sub-wavelength regions. The objective of this study is to develop an ET system for elastic waves operating in the MHz range. It provides a new feasible solution for sub-wavelength acoustic imaging applications. A three-dimensional EAT architecture is studied through a numerical model using the finite element method (FEM). The EAT structure is based on the Fabry-Pérot resonance, complemented by a groove pattern[3]. Two blocks serving as the propagation medium, are connected by a cylinder functioning as a resonator, as shown by Fig1.a). The theoretical fundamental frequency, determined by the resonator's length and extensional velocity, is set at 667 kHz. Concentric grooves on the input side ensure wave conversion. The incoming longitudinal wave at the groove interface is converted into surface acoustic waves which are converging towards the pillar input. To quantify the acoustic energy transmission T, the mechanical displacement is measured. The transmission efficiency, denoted as η (f) = T²(f)α², where α is the geometrical factor, is defined to indicate the level of the EAT phenomenon in the current setup. As shown by Fig1.b), FEM results demonstrate, at f = 667kHz, η = 0.75 < 1 for no groove case, and η = 5 with input side grooves, i.e. more energy than geometrical consideration (η > 1). Adding a grooved structure at the input side has a significant impact on η, depending on the spatial distribution. Applications of this energy transmission enhancement include ultrasonic subwavelength microscopy. References: [1] T. W. Ebbesen, Nature, 391(6668):667(1998). [2] A.A. Maznev, O.B. Wright, Wave Motion 68(2017) 182-189 [3] T. Devaux, O.B. Wright, Sci. Adv. aay8507(2020)

Fichier non déposé

Dates et versions

hal-05384130 , version 1 (26-11-2025)

Identifiants

  • HAL Id : hal-05384130 , version 1

Citer

Jiacheng Chen, Lionel Haumesser, Rémi Rouffaud, Eun Bok, Marc Lethiecq, et al.. Numerical study of a Fabry-Perot based elastic EAT system at MHz regime. Anglo-French Physical Acoustics Conference 2024 (AFPAC), IOP; SFA, Jan 2024, Loch Lomond, United Kingdom. ⟨hal-05384130⟩
49 Consultations
0 Téléchargements

Partager

  • More