Finite element analysis of surface modes in phononic crystal waveguides

Abstract

The study of surface modes in phononic crystal waveguides in the hypersonic regime is a burgeoning field with a large number of possible applications. By using the finite element method, the band structure and the corresponding transmission spectrum of surface acoustic waves in phononic crystal waveguides generated by line defects in a silicon pillar-substrate system were calculated and investigated. The bandgaps are caused by the hybridization effect of band branches induced by local resonances and propagating modes in the substrate. By changing the sizes of selected pillars in the phononic crystal waveguides, the corresponding bands shift and localized modes emerge due to the local resonance effect induced by the pillars. This effect offers further possibilities for tailoring the propagation and filtering of elastic waves. The presented results have implications for the engineering of phonon dynamics in phononic nanostructures.

Finite element analysis of surface elastic waveguide based on pyramidal phononic crystal

“…The transmission spectrum is the sum of the square of the three absolute module displacement vector components; , calculated as a function of frequency. The output signal is integrated at the location of the outlet edge in the Figure 1(c) on the upper right surface of the waveguide, as a line parallel to the y direction, this function is an elastic energy recovering in the output of our waveguide [21].…”

“…Furthermore, a thick slab with periodic inclusions, in particulars holes [19], and periodic pillars [20][21][22], are theoretically studied [21], and experimentally demonstrated [17,23], to command the surface acoustic wave (SAW) propagation. For the pillars PnC waveguide, two types of band gaps exist.…”

Surface Acoustic Wave Gyroscopic Effect in an Interdigital Transducer

“…The thickness of Au layer was set to 0 nm, 300 nm, 600 nm, and 900 nm. The PML can gradually absorb the mechanical and electrical disturbances in the layer before they reach the outer boundaries [31,32]. This induces a decrease in model size.…”

Guiding of elastic waves in a two-dimensional graded phononic crystal plate

“…Based on a graded index inhomogeneity design, the focusing and collimation performance of structure-embedded acoustic lenses has been proposed [18][19][20]. Surface acoustic waves have been explored in-depth, which can be applied in material characterization, photon or phonon modulation, acoustic sensors and optomechanics [21,22]. Thus, tailoring the propagation of surface modes is significant for these multitudinous applications.…”