Acoustic transmission through compound subwavelength slit arrays
Ward, GP; Hibbins, AP; Sambles, JR; et al.Smith, JD
Date: 12 July 2016
Article
Journal
Physical Review B - Condensed Matter and Materials Physics
Publisher
American Physical Society
Publisher DOI
Abstract
The angular dependence of the transmission of sound in air through four types of 2D slit-arrays
formed of aluminium slats is explored, both experimentally and numerically. For a simple, subwavelength
periodic slit-array, it is well known that Fabry-Perot-like wave-guide resonances, supported
by the slit-cavities, hybridising with ...
The angular dependence of the transmission of sound in air through four types of 2D slit-arrays
formed of aluminium slats is explored, both experimentally and numerically. For a simple, subwavelength
periodic slit-array, it is well known that Fabry-Perot-like wave-guide resonances, supported
by the slit-cavities, hybridising with bound acoustic surface waves, result in ‘Enhanced Acoustic
Transmission’ at frequencies determined by the length, width and separation of each slit-cavity. We
demonstrate that altering the spacing or width of some of the slits to form a compound array (i.e.
an array having a basis comprised of more than one slit) results in sharp dips in the transmission
spectra, that may have a strong angular dependence. These features correspond to ‘phase resonances’,
which have been studied extensively in the electromagnetic case. This geometry allows for
additional near-field configurations compared to the simple array, whereby the field in adjacent cavities
can be out-of-phase. Several types of compound slit-array are investigated; one such structure
is optimised to minimise the effect of boundary-layer loss mechanisms present in each slit cavity,
thereby achieving a deep, sharp transmission minimum in a broad maximum
Physics and Astronomy
Faculty of Environment, Science and Economy
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