Topological Rainbow Trapping for Elastic Energy Harvesting in Graded Su-Schrieffer-Heeger Systems

Abstract

We amalgamate two fundamental designs from distinct areas of wave control in physics, and place them in the setting of elasticity. Graded elastic metasurfaces, so-called metawedges, are combined with the now classical Su-Schrieffer-Heeger (SSH) model from the field of topological insulators. The resulting structures form one-dimensional graded-SSH metawedges that support multiple, simultaneous, topologically protected edge states. These robust, enhanced localized modes are leveraged for applications in elastic energy harvesting using the piezoelectric effect. The designs we develop are first motivated by applying the SSH model to mass-loaded Kirchhoff-Love thin elastic plates. We then extend these ideas to using graded resonant rods, and create SSH models, coupled to elastic beams and full elastic half-spaces.

Bidirectional Rainbow Trapping in 1-D Chirped Topological Photonic Crystal

“…The appearance of rainbow trapping offers a novel technique for frequency routing of slow light [1]. After the formation of the first theoretical work, many successive methods were presented to realize rainbow trapping, such as metamaterials [1,2], metasurfaces [3], plasmonic structures [4][5][6], phononic crystals in one-dimensional (1D) [7] and two-dimensional (2D) [8], and photonic crystals (PCs), in 1D [9], 2D [10,11] and three-dimensional (3D) [12]. Most of the mentioned methods depend on either metallic or dielectric materials.…”

Highly Efficient and Broadband Achromatic Transmission Metasurface to Refract and Focus in Microwave Region

“…[1][2][3][4][5] With the rise of artificial metamaterials, researchers can design sub-wavelength unit cells and realize desired permeability and permittivity to modulate the wave front. [6][7][8] In recent years, scientists have realized 2D planar electromagnetic devices, which are called metasurface, such as, refraction devices, [36][37][38][39][40] metalenses, [41][42][43][44][45][46][47][48][49][50][51] and vortex generators. [52][53][54][55][56] In most of these devices, Lorentz resonance units are used.…”

“…In recent years, scientists have realized 2D planar electromagnetic devices, which are called metasurface, [ 9–35 ] such as, refraction devices, [ 36–40 ] meta‐lenses, [ 41–51 ] and vortex generators. [ 52–56 ] In most of these devices, Lorentz resonance units are used.…”

Waves in the cochlea and in acoustic rainbow sensors

“…The idea of rainbow trapping within the field of graded-index metamaterials was first proposed in photonics [3], and then was also introduced to disciplines of different wave types, such as plasmonics [4], seismic waves [5] and other types of elastic waves [6,7,8,9]. In the acoustics regime in particular, acoustic rainbow sensors [10,11,12,13,14] consist of arrays of elements, whose properties vary with position, which have strong wave dispersion and can enhance and spatially separate different frequency components of an incident acoustic wave.…”