On‐Chip Tightly Confined Guiding and Splitting of Surface Acoustic Waves Using Line Defects in Phononic Crystals

Abstract

Phononic crystals (PnCs) exhibit acoustic properties that are not usually found in natural materials, which leads to the possibility of new devices for the complex manipulation of acoustic waves. In this article, a micron-scale phononic waveguide constructed by line defects in PnCs to achieve on-chip, tightly confined guiding, bending, and splitting of surface acoustic waves (SAWs) is reported. The PnC is made of a square lattice of periodic nickel pillars on a piezoelectric substrate. The PnC lattice constant, pillar diameter, and pillar height are set to 10, 7.5, and 3.2 µm, respectively, leading to a complete bandgap centered at 195 MHz. Interdigitated transducers are monolithically integrated on the same substrate for SAW excitation. The guiding, bending, and splitting of SAWs in the phononic waveguide are experimentally observed through measurement of the out-of-plane displacement fields using a scanning optical interferometer. The combination of destructive interference due to the Bragg bandgap and the interaction of the propagating wave with the pillars around the channel results in a tight confinement of the displacement field. The proposed phononic waveguides demonstrate the feasibility of precise local manipulation of SAW that is essential for emerging frontier applications, notably for phonon-based classical and quantum information processing.

Stepless space-regulation of topological acoustic controller with high fault tolerance

“…The research on acoustic waveguide has always been a research hotspot. At present, the construction of acoustic waveguide is mainly based on the characteristic impedance mismatch of the background dielectric layer to limit the acoustic wave to a specific area for propagation [12][13][14][15][16][17][18] and the introduction of defects in the sonic crystals (SCs) to guide the acoustic wave [19][20][21][22][23][24]. In previous studies, limited to the size of the structure, the acoustic energy does not have the ability to transmit and receive acoustic energy in an arbitrary path, and will decay with the transmission distance, which undoubtedly limits the accuracy of the transmission and reception of acoustic energy and reduces the utilization rate of energy.…”

6H-SiC phoxonic microcavities with photonic and phononic bandgaps

“…By establishing phonon stop zones within the periodic structure of phononic crystals, 14 , 15 elastic wave propagation could be manipulated. While current phonon excitation and control methods primarily rely on piezoelectric systems, 16 these methods necessitate electrodes capable of detecting different frequencies and propagation directions, 17 thereby increasing the experimental complexity. In contrast, the use of laser radiation pressure enables fine-tuning of acoustic vibrations in the frequency range of megahertz to gigahertz 18 …”

Reconfigurable local-resonance elastic waveguides in piezoelectric phononic crystals plate

“…Electric field regulation is the most studied way of active modulation of phononic crystals. Adding piezoelectric material controls the bandgap by an external electric field to realize piezoelectric energy recovery (He et al, 2023), modulating bandgap (Zuo et al, 2022), and elastic wave transmission (Gao et al, 2023). It is also relatively common to construct defect paths using external circuits (Casadei et al, 2012; Kwon et al, 2015; Sepehri et al, 2022).…”