Terahertz acoustic wave on piezoelectric semiconductor film via large-scale molecular dynamics simulation

Self Cite

This paper reviews recent progress in acoustic metasurface and a novel concept denoted as topological acoustic/phononics for designing compact yet efficient acoustic devices. After a brief review of these research area and their impact on ultrasonic technologies, I first introduce some of our efforts to develop highly efficient sound absorption devices using acoustic metasurface. A resonance-based mechanism to achieve efficient absorption in the metasurface structures thinner than wavelength of the incident sound is briefly discussed and its extensions to broad spectrum are highlighted. Next a valley topological phononic system is introduced and its applications to the design of phononic waveguide are exemplified. I show the band structure design for extracting topologically protected edge mode as well as the numerical and experimental demonstration of the robustness of phononic waveguides constructed in both acoustic and elastic regimes.

Section: Valley Topological Elastic Waveguidementioning

confidence: 99%

Acoustic metasurfaces and topological phononics for acoustic/elastic device design

Tsuruta

2023

Self Cite

“…In particular, to obtain a high frequency, a large electromechanical coupling factor (K 2 ), a large quality (Q) factor, and a small temperature coefficient of frequency (TCF), SAW propagation modes have been studied by focusing on the material of the substrate used. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Leaky surface acoustic waves (LSAWs) and longitudinal-type LSAWs (LLSAWs) have a higher phase velocity than Rayleigh-type SAWs (R-SAW), 18) which is advantageous for application to high-frequency SAW devices. [19][20][21] However, they have inherent attenuation because they lose energy by continuously radiating bulk waves into the substrate.…”

Section: Introductionmentioning

confidence: 99%

High coupling and highly stable leaky surface acoustic waves on LiTaO₃ thin plate bonded to quartz substrate

Hayashi

Yamaya

Suzuki

et al. 2018

The propagation properties and resonance characteristics of leaky surface acoustic waves (LSAWs) and longitudinal-type LSAWs (LLSAWs) on a LiTaO3 (LT) thin plate bonded to an AT-cut quartz substrate were investigated experimentally. For the LSAWs and LLSAWs, the bonded structures of 36°Y-cut X-propagating LT (36°YX-LT)/AT-cut 90°X-propagating quartz (AT90°X-quartz) and X-cut 31°Y-propagating LT (X31°Y-LT)/AT-cut 45°X-propagating quartz (AT45°X-quartz) were fabricated, respectively. For the LSAW on 36°YX-LT/AT90°X-quartz, the electromechanical coupling factor (K2) of 11.1% was obtained at an LT thin-plate thickness of 0.25 wavelength, whereas K2 for a single LT substrate was measured to be 5.7%. For the LLSAW on X31°Y-LT/AT45°X-quartz, K2 increased from 2.8% for the single LT substrate to 7.2% at an LT thin-plate thickness of 0.14 wavelength. Furthermore, K2 of approximately 12% and the temperature coefficient of frequency (TCF) of 0 ppm/°C were theoretically obtained simultaneously for the LSAW on 36°YX-LT/AT-cut 90°X-quartz at a certain thin-plate thickness.

“…With the spread of mobile communication apparatus, further improvement of the characteristics of surface acoustic wave (SAW) devices is required. In particular, to obtain a high frequency, driving stationarity with temperature, and a high electromechanical coupling factor, substrate structures such as thin-film loading structures [1][2][3][4][5][6][7][8][9][10][11][12] and bonding structures between material substrates 13,14) have been studied. Along with these studies, the accurate evaluation of the acoustical losses of substrate materials and loaded thin films is required to design SAW devices.…”

Section: Introductionmentioning

confidence: 99%

Propagation properties of leaky surface acoustic wave on water-loaded piezoelectric substrate

Suenaga

Suzuki

Kakio

et al. 2018

To evaluate acoustical loss mainly due to Rayleigh scattering loss of a thin film material using a line-focus-beam ultrasonic material characterization system, surface acoustic waves (SAWs) were excited and detected using IDTs, the propagation properties of SAWs with and without water loading were measured, and the acoustical losses of amorphous SiO2 and Ta2O5 thin films deposited on 128°YX-LiNbO3 were evaluated by subtracting the calculated attenuation of leakage loss into water from the measured propagation loss of leaky SAWs (LSAWs) on water-loaded specimens. The results of the evaluation of acoustical losses using LSAWs with the SAW propagation mode of the small leakage loss were in good agreement with the measured propagation loss of the Rayleigh-type SAW corresponding to the acoustical loss.