Longitudinal wave steering using beam-type elastic metagratings

Kim, Shin Young; Lee, Woorim; Lee, Joong Seok; Kim, Yoon Young

doi:10.1016/j.ymssp.2021.107688

Cited by 28 publications

(6 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Despite successful applications of metasurfaces based on the generalized Snell's law, they can generate parasitic wave modes because the generalized Snell's law ignores higherorder diffraction wave modes. To avoid the formation of undesirable scattered fields, thereby preventing energy from leaking into the scattered waves, elastic metagratings [197][198][199][200][201] based on the diffraction theory have been investigated. The diffraction theory [202] can be written as…”

Section: Anomalous Transmission and Reflectionmentioning

confidence: 99%

“…If the diffraction theory is used, higher-order diffraction modes can be manipulated. Figure 13(a) shows a beam-type elastic metagrating attached to the traction-free boundary of a plate [197]. Figure 13(b) demonstrates that the elastic metagrating can anomalously reflect the S0 mode without generating any higher-order parasitic diffraction.…”

Section: Anomalous Transmission and Reflectionmentioning

confidence: 99%

“…Therefore, the mode conversion between longitudinal and transverse waves is a unique phenomenon that can only be observed in elastic waves. As the S0 and SH0 modes correspond well to the longitudinal and transverse wave modes in bulk elastic media, respectively, and experiments in a plate are more accessible to perform than in a three-dimensional Reprinted from [197], © 2021 Elsevier Ltd. All rights reserved. bulk specimen, wave analysis with guided waves has been preferred whenever applicable.…”

Section: Mode Conversionmentioning

confidence: 99%

See 2 more Smart Citations

Elastic metamaterials for guided waves: from fundamentals to applications

Lee,

Kim

2023

Smart Mater. Struct.

Self Cite

View full text Add to dashboard Cite

Guided waves, elastic waves propagating through bounded structures, play a pivotal role in various applications, including ultrasonic non-destructive testing and structural health monitoring. Recently, elastic metamaterials artificially engineered to exhibit physical properties not typically seen in nature have emerged as a ground-breaking approach, heralding a new era in guided wave-based technologies. These metamaterials offer innovative solutions to overcome the inherent constraints of traditional guided wave-based technology. This paper comprehensively reviews elastic metamaterials from their fundamental principles to diverse applications, focusing on their transformative impact in guided wave manipulation.

show abstract

Section: Anomalous Transmission and Reflectionmentioning

confidence: 99%

Section: Anomalous Transmission and Reflectionmentioning

confidence: 99%

Section: Mode Conversionmentioning

confidence: 99%

See 1 more Smart Citation

Elastic metamaterials for guided waves: from fundamentals to applications

Lee,

Kim

2023

Smart Mater. Struct.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Following this study, several reciprocal and nonreciprocal acoustic metagratings with various functionalities in both reflection and transmission have been proposed in the past few years enabling an unprecedented degree of control over the flow of acoustic waves [74]- [82]. Metagratings for rerouting other types of elastic waves (e.g., flexural waves) have also been recently reported [9], [83], [84].…”

Section: Metagratings For Different Wave Platformsmentioning

confidence: 99%

Metagratings for Efficient Wavefront Manipulation

Ra’di

Alù

2022

IEEE Photonics J.

View full text Add to dashboard Cite

Recently, it was revealed that conventional gradient metasurfaces are fundamentally limited on their overall efficiency to reroute the impinging waves towards arbitrary directions in reflection and transmission. Their efficiency is particularly limited for extreme wavefront transformations. In addition, due to the fastly varying impedance profiles that these surfaces require, they usually need high-resolution fabrication processes, limiting their applicability and overall bandwidth of operation. To address these issues, the concept of metagrating was recently introduced, enabling engineered surfaces capable of manipulating light with unitary efficiency even in the limit of extreme wavefront manipulation. Metagratings are periodic or locally periodic arrays operated in the few-diffraction order regime. Their unit cell contains carefully designed scatterers that, in contrast with conventional metasurfaces, do not need to support a continuous gradient of surface impedance, and consequently are far simpler to fabricate and can afford broader bandwidths because of the larger footprint of the constituent elements. Tailoring the coupling towards the few available diffraction channels, metagratings enable wavefront transformations with high efficiency. In this paper, we review the physical mechanisms behind the functionality of metagratings and provide an overview and outlook of the recent progress in this field of science and technology.

show abstract

“…One example is the elastic metagrating proposed by S. Y. Kim et al, which contains slender and straight elastic beams to realize anomalous reflections of longitudinal waves [33]. P. Packo et al also proposed a grating structure to achieve anomalous reflection and refraction of flexural waves [34].…”

Section: Introductionmentioning

confidence: 99%

Elastic Metagratings with Simultaneous Modulation of Reflected and Transmitted Waves

2022

View full text Add to dashboard Cite

Elastic metagratings enabling independent and complete control of both reflection and transmission of bulk longitudinal and transverse waves are highly desired in application scenarios such as non-destructive assessment and structural health monitoring. In this work, we propose a kind of simply structured metagrating composed only of elliptical hollow cylinders carved periodically in a steel background. By utilizing the grating diffraction theory and genetic algorithm, we endow these metagratings with the attractive functionality of simultaneous and high-efficiency modulation of every reflection and transmission channel of both longitudinal and transverse waves. Interesting wave-front manipulation effects including pure mode conversion and anomalous deflection along the desired direction are clearly demonstrated through full-wave numerical simulations. Due to its subwavelength thickness and high manipulation efficiency, the proposed metagrating is expected to be useful in the design of multifunctional elastic planar devices.

show abstract

Longitudinal wave steering using beam-type elastic metagratings

Cited by 28 publications

References 34 publications

Elastic metamaterials for guided waves: from fundamentals to applications

Elastic metamaterials for guided waves: from fundamentals to applications

Metagratings for Efficient Wavefront Manipulation

Elastic Metagratings with Simultaneous Modulation of Reflected and Transmitted Waves

Contact Info

Product

Resources

About