Transmission Of Acoustic Waves Research Articles

Gigahertz Acoustic Delay Lines in Lithium Niobate on Silicon Carbide With Propagation-Q of 11174

This work demonstrates gigahertz wideband acoustic delay lines (ADLs) with record-breaking propagation-Q using a thin-film X-cut lithium niobate on silicon carbide (LiNbO3-on-SiC) platform. Benefiting from the high bulk wave velocity and excellent mechanical <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{f}\times \text{Q}$ </tex-math></inline-formula> of SiC, the shear horizontal surface acoustic wave (SH-SAW) excited by unidirectional transducers propagates in the top-surface of LiNbO3-on-SiC with low acoustic loss. The zero power flow angle (PFA) of −3° to +Y axis is obtained through simulation analysis and experiment validation, which leads to acoustic wave transmission perpendicular to the electrodes. Oriented at zero PFA, the fabricated ADLs show scalable center frequencies from 1.19 GHz to 2.11 GHz, 3-dB fractional bandwidth ranging from 2.7% to 11.5%, and a record-high propagation-Q of 11174. The performance has shown the great potential of the LiNbO3-on-SiC acoustic platform for various signal processing applications.

Identification of acoustic wave transmission mechanism to efficiently harvest the acoustic energy from gaseous flow in a pipeline

ABSTRACT A novel efficient acoustic wave transmission mechanism for extracting acoustic energy generated from gas flow pulses in a pipeline is proposed herein. The system comprises a main pipe, a side branch, and an energy harvester mounted thereon. Because pressurized gas flows through the main pipe, the side branch is essential for investigating the acoustic energy-harvesting mechanism installed thereon. Because the most important aspect of this study is the determination of the side branch location, the acoustic modal behavior of the gas flow field must be accurately predicted in advance. Finite element analysis (FEA) was performed to accomplish this task and then experiments were conducted to validate the FEA results. The two sets of results were well-matched, revealing a maximum root-mean-squared open-circuit voltage of 47.8 mV and a maximum power output of 100 μW when the side branch was installed at the pressure antinode point on the main pipe with a length of 1 m. We believe that the results obtained in this study provide substantial guidance for optimally installing acoustic energy harvesters in gas-carrying pipeline systems.

Electromagnetically induced acoustic transparency amplifier using a superconducting transmon circuit

We present a scheme for the amplification of electromagnetically induced acoustic transparency (EIAT) in a superconducting transmon circuit. Recently, EIAT has been demonstrated experimentally in a three-level ladder-type superconducting artificial atom [G Andersson et al, Phys. Rev. Lett. 124, 240 402 (2020)]. In this experiment, the authors have noticed only 20% transmission of surface acoustic waves (SAW) due to limited linewidth of the EIT window. Here we utilize an additional microwave field to enhance the transmission of SAW. This additional field increases the coherence in the second excited state which causes the amplification in transmission and the reduction in corresponding group velocity is achieved.

Energy trapping in a phononic crystal cavity enhanced by nonreciprocal acoustic wave transmission

Defect mode induced energy trapping at the bandgap frequency of a phononic crystal has been widely explored. Unlike this extensively used mechanism, this work reports the use of nonreciprocity in the transmission band to trap energy inside a phononic crystal cavity. Passive nonreciprocity is due to natural viscosity of the background liquid (water) and asymmetry of aluminum scatterers. The level of non-resonant energy trapping was compared for three cavities with different symmetry. Enhancement of energy trapping at a frequency of 624 kHz was observed experimentally for the cavity where nonreciprocity suppresses acoustic radiation into environment. Experimental results were further investigated and confirmed using finite element numerical analysis.

Noise reduction through periodic serial side branches containing two defects

Noise pollution is a challenging issue requiring the development of acoustic systems that can reduce noise. Besides the environmental impacts of noise pollution, it can cause serious health problems. This work originally discusses noise reduction using a new configuration of side branches grafted in series with different terminations. The combination of two serial resonators shows acoustic coupling effects. This effect is used to increase localized modes of two serial defective resonators located in the middle of the structure. The transmission of acoustic waves can be controlled by the dimensions of the introduced defects as well as their boundary conditions. We also show that defects can totally filter the transmission of the pass-bands. The proposed structure can then play the role of an acoustical filter.

Research on the Archaeoacoustic Simulation of Daxiong Main Halls in Chinese Buddhist Temples Through Comsol Tool

The acoustic analysis plays an irreplaceable role in obtaining information on Chinese Buddhist main halls tradition and relative practice that includes sound, deepening our comprehension of Chinese Buddhist architectural heritage. Various ceremonies and dojos constitute rich types of Buddhist main halls’ sound fields. In this paper, the indoor sound fields of four main halls in the Buddhist temples are researched and compared. This paper used Sketchup to build the models and simulate sound fields when conducting ceremonies and dojos using Comsol Multiphysics software. The four main halls are Chongshan temple main hall, Xiantong temple main hall, Shuxiang temple Manjusri hall and Bodhisattva Top main hall, which are located in separately four temples of Shanxi Wutai mountain in China. Targeting three acoustic parameters including the reverberation time(RT), the first ray arrival time(Re1first) and surface sound pressure level(SPL) distribution, we simulated the acoustic effect of the space occupancy, Buddha realm space and worship space, indicating that the acoustic wave diffusion rate was positively correlated with proportion of hall height to depth, while the first arrival time is exactly the opposite. The largest RT at 2000Hz(about 1.3s)in the shortest period for 500Hz voice was observed in the main hall of Pusa Peak, while T60 even reached 4s in Xiantong temple main hall. The acoustic wave transmission rate was positively correlated with proportion of hall’s height to depth, but the first ray arrival time was the opposite. The main hall of Pusa Peak had the shortest (0.0150s) first ray arrival time，the Shuxiang temple main hall had the longest time(0.0381s). In all the cases, appearing of the "sound shadow area" of the surface SPL distribution and the uneven sound energy distribution showed pillars in the middle space exerting significant impact on the acoustics of the Daxiong main hall.

Experimental study on the transmission characteristics of near-field detonation noise into water

To study the transmission characteristics of near-field detonation noise into water, the detonation noise transmission system is built on a laboratory-scale water tank using a detonation tube with a diameter of 30 mm. The interaction of the detonation gas jet with the air–water interface, the development of the cavity, and the growth of the liquid column are experimentally observed by a high-speed camera. The spectral distribution characteristics of detonation noise above and below the interface are recorded by a microphone, a hydrophone, and an underwater blast sensor. Analysis of the experimental images shows that the size of the cavity increases with increasing filling pressure and decreases with increasing nozzle height. By normalizing the evolution time of the cavity with the cavity lifetime, it is concluded that the time for the cavity to develop to the deepest is about 0.27, independent of the filling pressure. The pressure field data analysis results show that the main frequencies of the detonation sound waves are 100 and 400 Hz, and the frequency distribution has nothing to do with the filling pressure. Through the defined acoustic wave energy transmission coefficient, it is demonstrated that the detonation acoustic wave transmission coefficient decreases with the increase in the frequency, and the shock wave transmission coefficient decreases with the increase in the angle.

Quasi-acoustic impedance matching distributed opto-mechanical sensor with aluminized coating optical fibers.

The uncoated single-mode fiber has been extensively researched as an opto-mechanical sensor since it can achieve substance identification of the surrounding media by exciting and detecting transverse acoustic waves via forward stimulated Brillouin scattering (FSBS), but it has the danger of being easily broken. Although polyimide-coated fibers are reported to allow transverse acoustic waves transmission through the coating to reach the ambient while maintaining the mechanical properties of the fiber, it still suffers from the problems of hygroscopic property and spectral instability. Here, we propose a distributed FSBS-based opto-mechanical sensor using an aluminized coating optical fiber. Benefiting from the quasi-acoustic impedance matching condition of the aluminized coating and silica core cladding, aluminized coating optical fibers not only have stronger mechanical properties and higher transverse acoustic wave transmission efficiency but also have a higher signal-to-noise ratio, compared with the polyimide coating fibers. The distributed measurement ability is verified by identifying air and water around the aluminized coating optical fiber with a spatial resolution of 2 m. In addition, the proposed sensor is immune to external relative humidity changes, which is beneficial for liquid acoustic impedance measurements.

Acoustic wave transmission through periodic parallel resonators

Noise pollution is one of the serious problems that can cause discomfort or harm to the health of people besides the environmental impact. Periodic structures play an important role in noise reduction. The interface response theory is used in this work to study the transmission spectrum and the band structure of a new configuration of a periodic structure. This later has two resonators grafted one in front of the other with two different boundary conditions at their extremities. We call this structure the Combination of Closed and Open side Resonators (CCOR). We show that the proposed structure presents large acoustic band gaps, which provide an important attenuation of sound that can be used as an acoustic filter. The presence of two parallel defective resonators inside the CCOR structure gives rise to two localized modes inside band gaps. The numerical results obtained by the interface response theory are compared with those of the transfer matrix and they remain the same. This study originally presents a way of the exploitation of the positive effect of the mutual interaction of defect modes in order to increase defect modes transmission as well as noise attenuation.

Acoustic edge mode in spiral-based metamaterials at subwavelength scale

Recently, the quantum effect of condensed matter physics is introduced into the acoustic field, which lays a new pathway to manipulate the acoustic wave. However, the acoustic topological insulator based on Bragg scattering requires their lattice constant to be comparable with the wavelength. In this paper, a novel subwavelength spiral element on the basis of the Archimedean spiral is proposed. Thanks to the central resonator with a slender curved channels scheme, the subwavelength Dirac cone forms in the band structure. The eigenfrequency of the element can be changed by the spiral geometric parameters, which triggers the topological phase transition characterized by opposite valley Chern numbers. The backscattering-immune unidirectional transmission edge state exists at different topological boundaries, suggesting its great robustness even at the sharp bends. Also the topological edge modes along the Z-shaped interfaces are verified by the experiments and the calculation, which provides an effective structure to control the low frequency acoustic wave transmission.

Acoustic wave transmission of FG composite cylindrical shells integrated with piezoelectric patches

In this study, wave propagation through the air-filled double-walled functionally graded (FG) cross-ply layered cylindrical shells with an arrangement of piezoelectric patches is investigated in the framework of the first-order shear deformation assumption (FSDA). Acting as both actuator and sensor, these piezoelectric patches are acted upon by an electric potential. Power law model is utilized to take into account material characteristics distribution along the thickness of each shell. The derivation of vibroacoustic equations in the form of coupled relations is realized by implementing Hamilton’s principle. An analytical method is exploited to solve the coupled vibroacoustic governing equations in conjunction with double Fourier series, and the final result is the desired sound transmission loss (STL) equation. Parameter studies reveal the impacts of the of ply angle, functionally graded index, incident angles, acoustic cavity depth, external electric voltage, and characteristics of piezoelectric patches on STL through the double-walled cylindrical shells.

Large surface acoustic wave nonreciprocity in synthetic antiferromagnets

We have studied the transmission of surface acoustic waves (SAWs) in ferromagnetic/non-magnetic/ferromagnetic tryilayers. The SAW scattering matrix is studied for devices with various non-magnetic spacer thickness, which defines the strength of the interlayer exchange coupling. We find the SAW transmission amplitude depends on its propagation direction when the two ferromagnetic layers are coupled antiferromagnetically. The degree of such SAW nonreciprocity increases with increasing exchange coupling strength and reaches 37 dB mm−1 for a device with the thinnest spacer layer. These results show the potential of interlayer exchange coupled synthetic antiferromagnets for viable acoustic nonreciprocal transmission devices, such as circulators and isolators.

Acoustic wave transmission characteristics of stiffened composite shell systems with double curvature

In this study, acoustic performance of the stiffened doubly curved shells is studied for the first time. Since these structures reinforced via equally spaced stiffeners are found in many engineering designs, the inspection of their sound insulation is remarkably recommended. For sound analysis of such models, it is essential to provide a solution strategy wherein the acoustic equations to be simultaneously solved besides the stiffened shell equations. Accordingly, based on modeling the construction as a finite shell using shear deformation shallow shell theory (SDSST), wave propagation is performed through a doubly curved body reinforced by a stiffener. Before validating the sound transmission loss (STL) spectrum with previous outcomes, the convergence criterion is checked. Moreover, the acoustic efficiency of the proposed stiffened system is also evaluated. It is shown that the stiffened model using both ring and stringer improves the sound characteristics of structure in the entire frequency domain. Finally, an optimization scheme based on genetic algorithm (GA) is presented to maximize the STL and minimize the weight of the structure focusing on geometrical characteristics of the stiffener. This study proposes a strategy that can be applied to predict the acoustic features of the stiffened systems to achieve better sound insulation.

Frequency-robust preconditioning of boundary integral equations for acoustic transmission

The scattering and transmission of harmonic acoustic waves at a penetrable material are commonly modelled by a set of Helmholtz equations. This system of partial differential equations can be rewritten into boundary integral equations defined at the surface of the objects and solved with the boundary element method (BEM). High frequencies or geometrical details require a fine surface mesh, which increases the number of degrees of freedom in the weak formulation. Then, matrix compression techniques need to be combined with iterative linear solvers to limit the computational footprint. Moreover, the convergence of the iterative linear solvers often depends on the frequency of the wave field and the objects' characteristic size. Here, the robust PMCHWT formulation is used to solve the acoustic transmission problem. An operator preconditioner based on on-surface radiation conditions (OSRC) is designed that yields frequency-robust convergence characteristics. Computational benchmarks compare the performance of this novel preconditioned formulation with other preconditioners and boundary integral formulations. The OSRC preconditioned PMCHWT formulation effectively simulates large-scale problems of engineering interest, such as focused ultrasound treatment of osteoid osteoma.

Finite element simulation of transmission and reflection of acoustic waves in the ultrasonic transducer

In scanning acoustic microscopy (SAM), the image quality depends on several factors such as noise level, resolution, and interaction of the waves with sample boundaries. The theoretical equations for the reflection coefficient and transmission coefficient are suitable for plane boundaries but fail for curved/rough boundaries. We presented a finite element method-based modeling for the loss coefficients in SAM. A focused and unfocused lens with a flat object, furthermore a focused lens with a curved object was selected for loss coefficients calculation. The loss calculation in terms of energy for defining the acoustic reflection and transmission losses and its dependence on the radius of curvature of the test object has also been presented.

Reflection and transmission of acoustic waves through the bridging membrane junctions

The reflection and transmission of fluid-structure coupled waves through a membrane bounded cavity are discussed. The vertical walls of the cavity at the junctions are assumed to be the rigid plates or the elastic membranes. The problem with rigid vertical plates is amenable by following the traditional Mode-Matching technique (MMT). However, if the rigid vertical plates at junctions are replaced with elastic membranes, the standard mode-matching procedure fails. Alternatively, the mode-matching tailored-Galerkin (MMTG) approach is developed. In this approach, the Galerkin technique to express the displacements of the bridging membranes is adopted. The method chosen herein provides a unique description of displacements to cater a verity of edge conditions on the joints of vertical membranes. The low frequency approximation (LFA) which valid only in low frequency regime, for the rigid plates and membrane heights is formulated and compared. To analyze the scattering behavior, two types of incident forcing, structure-born mode and fluid-born mode, are assumed. It is found that the material properties of vertical surfaces of the cavity at junctions as well as the selection of edge conditions in case of vertical membranes significantly affect the scattering powers and the transmission loss.

Reciprocity of thermal diffusion in time-modulated systems

The reciprocity principle governs the symmetry in transmission of electromagnetic and acoustic waves, as well as the diffusion of heat between two points in space, with important consequences for thermal management and energy harvesting. There has been significant recent interest in materials with time-modulated properties, which have been shown to efficiently break reciprocity for light, sound, and even charge diffusion. However, time modulation may not be a plausible approach to break thermal reciprocity, in contrast to the usual perception. We establish a theoretical framework to accurately describe the behavior of diffusive processes under time modulation, and prove that thermal reciprocity in dynamic materials is generally preserved by the continuity equation, unless some external bias or special material is considered. We then experimentally demonstrate reciprocal heat transfer in a time-modulated device. Our findings correct previous misconceptions regarding reciprocity breaking for thermal diffusion, revealing the generality of symmetry constraints in heat transfer, and clarifying its differences from other transport processes in what concerns the principles of reciprocity and microscopic reversibility.

Nonreciprocal Sound Propagation via Cascaded Time-Modulated Slab Resonators

In this work, we demonstrate nonreciprocal acoustic wave transmission in two-cascaded Fabry-Perot-like slab resonators undergoing time modulation of their effective density. A phase difference is introduced into the time modulation between the two coupled resonators to produce spatial bias to access unidirectional wave propagation. A theoretical model based on plane-wave expansion and the transfer-matrix method is developed to study the Fabry-Perot-based system. The theoretical model allows rapid and precise characterization of the acoustic dispersion, with results in excellent agreement with finite-element-based numerical simulations. We demonstrate acoustic nonreciprocity behavior for the fundamental acoustic mode and further show that, with proper optimization, the coupled Fabry-Perot-based device can achieve nonreciprocal acoustic frequency conversion. This work could inspire the design of simple and compact nonreciprocal acoustic devices for efficient wave control.

Ultrasonic investigation of the evaporation dynamics of subnanoliter droplets

With the development of ink jet printers or spotters for biological applications, the control size and homogeneity of small fluids as well as their successful deposition on various substrates has gained significant importance. We study the impingement process of such small droplets onto a solid substrate and investigate their evaporation and drying process by means of surface acoustic wave (SAW) transmission experiments. We observe a strong fluid-SAW interaction resulting in an attenuation which toward the end of the evaporation and drying process exhibits characteristic oscillations being related to temperature, SAW amplitude, and fluid properties such as viscosity and wetting angle. It is found that oscillations can only be seen in pinned, very flat droplets, while the pinning can be roughly controlled via the SAW amplitude. The frequency of those characteristic oscillations is superlinear with respect to temperature, rather proportional to the evaporation rate and can change drastically depending on the liquid used. In our experiments, isopropanol, ethanol, and water with various glycerol concentrations were loaded onto the SAW delay line. Based on the experimental results, simulations using the finite element method were performed. We find that a standing wave pattern within the droplet is responsible for the transmission oscillations. These findings might lead to new methods, e.g., sensory systems, being able to examine droplets according to their physical or chemical properties.

Quantum communication with itinerant surface acoustic wave phonons

Surface acoustic waves are commonly used in classical electronics applications, and their use in quantum systems is beginning to be explored, as evidenced by recent experiments using acoustic Fabry–Pérot resonators. Here we explore their use for quantum communication, where we demonstrate a single-phonon surface acoustic wave transmission line, which links two physically separated qubit nodes. Each node comprises a microwave phonon transducer, an externally controlled superconducting variable coupler, and a superconducting qubit. Using this system, precisely shaped individual itinerant phonons are used to coherently transfer quantum information between the two physically distinct quantum nodes, enabling the high-fidelity node-to-node transfer of quantum states as well as the generation of a two-node Bell state. We further explore the dispersive interactions between an itinerant phonon emitted from one node and interacting with the superconducting qubit in the remote node. The observed interactions between the phonon and the remote qubit promise future quantum-optics-style experiments with itinerant phonons.