Refraction-type sonic crystal junction diode

Abstract

Unidirectional sound transmission across a junction of two square sonic crystals with different orientations and lattice constants is numerically investigated. Re-scaling and rotating the wave vectors through refractions across the air-first sonic crystal interface and the junction, respectively, facilitate coupling into the spatial modes of the second crystal. Unidirectional transmission, demonstrated through finite element method simulations, is accomplished between 10.4 kHz and 12.8 kHz. Transmission values to the right and left are greater than 60% and less than 1.0%, respectively, between 11.0 kHz and 12.4 kHz, resulting in a contrast ratio greater than 0.9.

Experimental demonstration of deflection angle tuning in unidirectional fishnet metamaterials at millimeter-waves

“…Different strategies have been proposed, including those based on higher diffraction orders, [6][7][8][9][10][11] polarization conversion, 12,13 and wave manipulation in prism-like structures. 14,15 For the first and second ones, asymmetry in transmission is achieved due to the use of different transmission channels that are open for each of the two opposite illumination directions at fixed frequency. The third one can be achieved just owing to the effect of inclining interface(s), without a formal addition of new channels.…”

Diffraction inspired unidirectional and bidirectional beam splitting in defect-containing photonic structures without interface corrugations

“…Asymmetric transmission is a very general phenomenon, which can be connected not only with diffractions at the interfaces [6][7][8][9][10][11] but also with polarization conversion, 12-15 direction manipulation by inclining interfaces like in prism-shaped configurations, [16][17][18][19] etc. Metamaterials may promise more compact performances for devices based on diffraction inspired asymmetric transmission, [20][21][22] but their application to splitting has not yet been studied.…”

Reducing symmetry in topology optimization of two-dimensional porous phononic crystals

“…2 Resulting from the destructive interference between incident elastic/acoustic waves and reflections from the scatterers, bandgaps inherently become the basis of the most applications of PnCs. Promising applications of PnCs include sound insulation, 3 sound barrier, 4 damping, 5,6 acoustic resonators, 7,8 elastic/acoustic waveguides, 9 filters, 10 frequency sensing, 11,12 acoustic mirrors, 13 switches, 14 lenses, 15 energy harvesting, 16 negative refraction, 17,18 self-collimation, 19,20 acoustic mirages, 14 rectification, 21 acoustic diodes, 22,23 and thermal conductance. 24,25 In recent years, some researchers have been conducted and focused on topology optimization of photonic crystals (PtCs), 26,27 PnCs [28][29][30][31][32][33] and phoxonic crystals (PxCs).…”