Acoustic dispersive prism

Abstract

The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz–1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

Topological acoustic polaritons: robust sound manipulation at the subwavelength scale

“…In addition, our system is opened to its environment, and by operating within the sound cone, topological acoustic states can be coupled to the radiation continuum. This opens interesting application perspectives for topological acoustic polaritons, which may enable disruptive advances in transducer or sensing technologies, including a new generation of topologically protected acoustic leaky wave antennas [73][74][75][76] and subwavelength imaging systems [67]. In addition, the slow group velocity of topological acoustic polaritons may be of significant interest to realize robust slow wave systems, avoiding their typical sensitivity to disorder.…”

Monochromatic Composite Right/Left Handedness in the Quantized Composite Right/Left Handed Transmission Line

“…Since the first experimental demonstration of a left-handed (LH) structure with simultaneously negative effective permittivity and permeability [1][2][3][4][5] in the microwave frequencies, [6] some authors [7][8][9][10] adopted an engineering approach and developed the generalized transmission line (TL) theory to exhibit unprecedented features [11][12][13][14][15] in terms of performances or functionalities. These efforts resulted in the elaboration of the powerful CRLH concept, in which the right-handedness and left-handedness accompanying the positive/negative refraction index achieved in the higher and microwave frequency bands, respectively, and the CRLH-TL led to a suite of novel guided-wave, [16] radiated-wave, [17] and refracted-wave devices and structures.…”

Improving directional radiation quality based on a gradient amplitude acoustic leaky wave antenna

“…In previous studies, the CRLH-TL ALWAs have been designed using an array of side holes and membranes that were periodically loaded along the waveguide, where power could leak along the waveguide through the periodical side holes [5][6][7]. So far, acoustic antennas have attracted considerable attention because they exhibit various unique applications, such as single sensor direction-finding [7], acoustic dispersive prisms [8], sound source localization [9] and noise control [10][11][12]. Despite the tremendous prospect of these devices with acoustic steering, they will unavoidably bring many side lobes with the increase of unit cell number and size.…”