arXiv subjects

Tingfeng Ma

Publications and source records attributed to Tingfeng Ma.

14 recordsLinked to original sources

arXiv2026

Experimental Realization of Topological Surface Acoustic Wave Resonances under Surface Liquid Loading for Micro-volume sample Sensings

Surface acoustic wave (SAW) sensors, owing to their high operating frequencies, compatibility with planar micro-fabrication, and exceptional sensitivity to surface perturbations, are widely used in lab -on-a-chip and biomedical diagnostic applications. However, conventional SAW sensors operating in liquid environments suffer from substantial energy dissipation, which markedly reduces their quality factors (Q factors) and limits sensing reliability. Here, we design and fabricate a topological SAW resonant sensor for surface liquid loading by exploiting interference coupling between topological interface states and resonant cavities. The band structures are validated using a semi-analytical plane wave expansion-finite element method. The device requires only 0.04 uL of sample and enables concentration sensing of NaCl and glucose solutions, with sensitivities of up to 190 kHz/% for NaCl and 101.8 kHz% for glucose, respectively, and a concentration resolution of 0.01%. This work offers a potential technological route towards high-performance SAW biomedical chips for micro-volume sample analysis.

physics.app-ph↗

arXiv2026

Large area Waveguide Energy Harvesting Based on Fully Polarized Elastic Topological Metamaterials

To address the challenge that elastic wave energy can only transmit through narrow path waveguides in topological metamaterials, the proposal of large area waveguides effectively breaks through this technical bottleneck. Nevertheless, elastic waves are vector waves with complex multi component transmission characteristics. Realizing the cooperative transmission of in plane and out of plane fully polarized components poses substantial challenges for elastic wave energy transmission and trapping applications. To tackle the above mentioned problems, this paper proposes a fully polarized elastic topological heterostructure based on the quantum valley Hall effect. First, symmetric unit cell structures are designed to obtain unit cells with distinct topological properties for in plane and out of plane modes, and multiple types of supercell structures are fabricated to realize the simultaneous transmission of fully polarized elastic wave energy for both in plane and out of plane components. Furthermore, a gradient valley locked structure is designed using large area waveguide states to constrain and converge the transmitted energy, and its energy harvesting performance is analyzed. The results demonstrate that the proposed structure enables coupled transmission of fully polarized elastic wave components. Moreover, the energy harvesting capability of the gradient valley locked phononic crystal plate is approximately 4.79 times that of conventional single component transmission structures, which greatly improves the efficiency and transmission stability of acoustic energy harvesting. This work provides new insights for the engineering application of topological metamaterials in the field of energy harvesting.

physics.app-ph↗

arXiv2026

Topological Skyrmion-type microparticle manipulation based on surface acoustic wave phase modulations

Surface acoustic wave (SAW) micromanipulation enables the precise, non-contact handling of microscale particles and has attracted considerable interest in microfluidics and biomedicine. However, conventional SAW platforms generally rely on simple interference fields which are susceptible to fabrication imperfections and environmental perturbations, resulting in limited trapping stability. Here, we develop a SAW-based acoustofluidic platform that generates an acoustic skyrmion lattice through the coherent interference of three SAWs. The topologically structured field provides robust phase singularities and a stable gradient-force landscape, enabling microparticles to be localized at predefined lattice sites and supporting controllable rotational manipulation. Independent modulation of the amplitude and phase of the electrical inputs allows the field strength to be tuned for particles of different sizes. Numerical simulations and proof-of-concept experiments confirm particle trapping and ordered lattice assembly in the acoustic skyrmion field, demonstrating the feasibility of translating topological acoustic textures into practical on-chip manipulation functions. This reconfigurable strategy offers a route to robust SAW manipulation and may support applications in single-cell analysis, three-dimensional cell assembly, high-throughput screening, and microscale and nanoscale device assembly.

physics.app-ph↗

arXiv2026

Non-Hermitian-induced higher-order topological phases in acoustic fractal lattices

For fractal (non-integer-dimension) geometries in Hermitian system, high-order topological phases were realized in the past few years, for which, it is difficult to tune the energy concentration degree of topological states flexibly and smoothly. Non-Hermiticity method is expected to solve this problem. However, in non-integer-dimension system, the non-Hermitian-fractal coupled topological mechanism is unclear and topological phases induced by non-Hermiticity remain unrealized. By introducing a loss contrast in a fractal lattice, this study proposes a non-Hermitian route to realize higher-order topological phases in acoustic fractal lattices with good tunability. Based on the tight-binding approximation, calculations on the Hamiltonian of the system yield the wave-function distribution of the zero-energy modes, revealing the formation mechanisms and conditions for the topological phase transitions induced by non-Hermiticity in acoustic fractal lattices. We numerically and experimentally realize non-Hermitian-induced topological edge and corner states in a fractal structure. Furthermore, a tunable acoustic energy concentrator has been realized, namely, the degree of acoustic energy localization can be tuned conveniently by merely adjusting the loss contrast, rather than redesigning the structure parameters. This work not only establishes an effective mechanism for manipulating higher-order topology in complex fractal geometries through non-Hermiticity but also provides a theoretical framework for exploring exotic topological states of matter in non-integer dimensions.

physics.app-ph↗

arXiv2025

Realization of Friedrich-Wintgen QBIC with high Q-factors based on acoustic-solid coupling and sensing applications

In recent years, bound states in the continuum (BICs) have attracted extensive attentions in the sensing field due to their theoretically ultra-high resonance quality factors (Q-factors). Among them, Friedrich-Wintgen (F-W) BICs, which arise from the interference between different coupled modes, are particularly promising for acoustic sensing applications owing to the easy realization. Most existing F-W BICs are realized in open systems through the interference between waveguides and resonant cavities. However, with increasing demands for higher resolution and sensitivity in modern chemical and biological sensing, the practically measured Q-factors of conventional open-system F-W BICs often fall short of expectations.In this work, we introduce F-P resonance via acoustic-solid coupling to explore the formation mechanism and realization method of high-Q F-W BICs in quasi-closed systems, and further investigate their application in gas sensing. A coupled resonator model combining elastic and acoustic waves in a quasi-closed cavity is first established. Coupled mode theory is employed to calculate the eigenmodes of both localized and radiative modes. Based on this, the Hamiltonian matrix of the coupled system is constructed, from which the acoustic transmission spectrum is derived. The results show that the Q-factor of the F-W BIC induced by acoustic-solid coupling is significantly higher than that of open systems, which is further validated by experiments.Based on this, a gas concentration sensing technique based on acoustic-solid coupled F-W BIC behavior is developed. A sensing device is fabricated accordingly, and gas concentration measurements are carried out. Experimental results demonstrate a pronounced response to gases with different concentrations, confirming the feasibility and reliability of this novel gas sensing approach.

physics.app-ph↗

arXiv2024

Tunable acoustic energy concentrations based on pseudo-spin locking waveguides and topological rainbow trappings

In this work, tunable acoustic energy concentrations are realized based on pseudo-spin locking waveguides and topological rainbow trappings. Firstly, a tunable pseudo-spin locking is proposed, and the broad acoustic energy transport and spin-locked one-way transport are verified. The results show that acoustic wave transports based on pseudo-spin locking waveguides are more robust to structure defects than conventional topological edge-state waveguides. Besides, topological rainbow trappings are realized by adjusting the distribution of liquid in tubes. Based on those, we investigate the coupling of the pseudo-spin locking waveguides and the topological rainbow trappings. The results show that high acoustic energy concentrations can be obtained conveniently by using the coupling energy concentrator based on the pseudo-spin locking waveguides and the topological rainbow trappings. The results present a novel method to concentrate acoustic wave energy, which is vital in the application field of acoustic sensings and microfludics. The according experimental verifications will be presented in the near future.

physics.app-ph↗

arXiv2024

Particle manipulations based on acoustic valley topological rainbow defect-state trapping

Acoustic microfluidic is an important technology in particle manipulations in biomedical analyses and detections. However, the particle-movement manipulations achieved by the standing surface acoustic wave is suitable for particles in a thin layer of fluids, however it is difficult to manipulate particles in deeper solutions due to the energy loss of surface acoustic waves. The traditional standing bulk wave method can realize the particle manipulation in deep solutions, but it cannot work properly for particle manipulation within a long distance due to the energy loss. In this work, the topological rainbow defect-state trapping is realized, the results show that an effect of point accumulation of acoustic pressure in the waveguide path exists, the position of maximum acoustic pressure can be adjusted flexibly by changing the frequency of the incident acoustic wave, based on which, long-distance movement and capture manipulations of particles in deep solution have been realized. The phenomenon presented in this work can provide a reliable method for manipulations of continuous long-distance particle movement and capture to meet the demand of multiple processing steps in biochemical analyses and detections. The experiment verification results will be presented in the near future.

physics.class-ph↗

arXiv2024

Topological resonance behaviors of surface acoustic waves under a surface liquid-layer loading and sensing applications

In this work, topological resonance behaviors of surface acoustic waves (SAW) under a surface liquid-layer loading are investigated. By revealing influences of the liquid-layer loading on wave velocity of SAW and topological indices (Berry curvature and Chern number) of topological interface-modes, a topological resonance peak with a high Q-factor is obtained based on couplings of a topological interface-mode waveguide and a resonant cavity under a surface liquid-layer loading. The results show that the degree of spatial-inversion-symmetry breaking resulting from structure parameters has an obvious influences on the topological resonance Q-factor, while the influences of the thickness of the liquid-layer loading on that is weak. It is worth noting that the topological resonance frequency is significantly sensitive to the liquid parameters. Based on that, a novel topological-resonance SAW liquid-phase sensor is proposed. Furthermore, sensing performances of this kind of sensor are simulated, which are used to sensing the concentration of hemoglobin, albumin, NaCl and NaI in aqueous solutions, and high sensitivities and Q-factors are obtained. The results presented in this paper can provide an important basis for the realization of highly sensitive and stable SAW micro-liquid-sample biomedical sensors in the future.

physics.app-ph↗

arXiv2024

Evolution of static to dynamic mechanical behavior in topological nonreciprocal robotic metamaterials

Based on the Maxwell-Beatty reciprocity theorem, static non-reciprocity has been realized by using nonlinearity, but this non-reciprocity has strict restrictions on input amplitude and structure size (number of units). Here, we propose a robotic metamaterial with two components of displacement and rotation, which uses active control to add external forces on the units to break reciprocity at the level of the interactions between the units. We show analytically and simulatively that breaking reciprocity at the level of the interactions directly leads to a strong asymmetric response of displacement in a static system, this displacement-specific characteristic not only has no restrictions on size, input amplitude, and suitable geometric asymmetry, but also can be transmitted to rotation by coupling under large deformation. After the evolution from statics to dynamics, asymmetric transmission and unidirectional amplification of vector solitons are both implemented in this system. Our research uncovers the evolution of static non-reciprocity to dynamic non-reciprocity while building a bridge between non-reciprocity physics and soliton science.

cond-mat.soft↗

arXiv2023

Anomalous size effects with fixed criticality in bistable flexible mechanical metamaterials

When the structure deformation is dominated by the low-energy deformation mode, the structure hardens with the increase in the size (number of units) at small sizes. This anomalous behavior will eventually disappear with the decay length of the finite structure converging to a size-independent characteristic quantity, but the specific critical point at which the anomalous behavior disappears still cannot be accurately and concisely described. Here, under two steady states of the bistable chain, we observed anomalous size effects with constant and oscillating criticality (the proportion of inhomogeneous deformation), two criticalities exactly separate the increasing and decreasing intervals of stiffness variation. They are interrelated due to the implied symmetries between the two steady states. On the other hand, they are distinguished because of the opposite superposition modes under the two steady states. Specifically, the constant criticality corresponds to the anomalous size effect achieved by the competition mechanism, while the oscillating criticality reveals an anomalous size effect achieved by the new mechanism (cancellation mechanism). In the anomalous size effect achieved by the cancellation mechanism, the singular characteristics generated by the completely cancelled deformation make it very robust. This robustness reflects in that the anomalous effect is no longer limited to linear small deformation, but it can still be observed stably in nonlinear large deformation. Our study reinterprets the anomalous size effect at a quantitative level, and the proposed cancellation mechanism expands the possible application range of this anomalous effect.

physics.app-ph↗

arXiv2023

Elastic fractal higher-order topological states

Fractal is an intriguing geometry with self-similarity and non-integer dimensions, the elastic-wave topological phase based on fractal structures has not been revealed up to now. In this work, elastic-wave higher-order topological states in fractal structures are investigated. Elastic real-space quantized quadrupole moment is calculated and used to characterize the topology of elastic fractal metamaterials, and formation conditions of topological phase transitions in elastic fractal systems are revealed. The topological edge and corner states of elastic waves in fractal structures are realized theoretically and experimentally. It is found that different from the acoustic fractal system, the topological outer and inner edge states can emerge separately in elastic fractal systems, which is important for the integrated sensing and particle manipulation in microfluidics. Besides, the results show that the robustness of the topological corner states in rhombus fractal structures is obviously stronger than that in Sierpinski fractal structures, and the physical mechanism is clarified. Compared with traditional elastic-wave topological insulators based on periodic structures, the richness of topological states in elastic fractal structures is much higher (for the Sierpinski fractal structure, the number of topological states is 156, much greater than that of the periodic structure (only 28)), which is vital in integrated sensing and energy-location applications. The topological phenomena of elastic fractal systems revealed in this work, provides an unprecedented way of controlling elastic waves, enriches the topological physics of elastic systems and breaks the limitation of that relying on periodic elastic structures. The results have great application prospects in high-Q resonators, high-resolution elastic-wave energy locations, energy harvester, and high-sensitivity sensors.

physics.app-ph↗

arXiv2015

An Analysis of Thickness-shear Vibrations of an Annular Plate with the Mindlin Plate Equations

The Mindlin plate equations with the consideration of thickness-shear deformation as an independent variable have been used for the analysis of vibrations of quartz crystal resonators of both rectangular and circular types. The Mindlin or Lee plate theories that treat thickness-shear deformation as an independent higher-order vibration mode in a coupled system of two-dimensional variables are the choice of theory for analysis. For circular plates, we derived the Mindlin plate equations in a systematic manner as demonstrated by Mindlin and others and obtained the truncated two-dimensional equations of closely coupled modes in polar coordinates. We simplified the equations for vibration modes in the vicinity of fundamental thickness-shear frequency and validated the equations and method. To explore newer structures of quartz crystal resonators, we utilized the Mindlin plate equations for the analysis of annular plates with fixed inner and free outer edges for frequency spectra. The detailed analysis of vibrations of circular plates for the normalized frequency versus dimensional parameters provide references for optimal selection of parameters based on the principle of strong thickness-shear mode and minimal presence of other modes to enhance energy trapping through maintaining the strong and pure thickness-shear vibrations insensitive to some complication factors such as thermal and initial stresses.

cond-mat.mtrl-sci↗

arXiv2015

Thickness-shear Vibration Frequencies of an Infinite Plate with a Generalized Material Property Grading along the Thickness

For quartz crystal resonators of thickness-shear type, the vibration frequency and mode shapes, which are key features of resonators in circuit applications, reflect the basic material and structural properties of the quartz plate and its variation with time under various factors such as erosive gases and liquids that can cause surface and internal damages and degradation of crystal blanks. The accumulated effects eventually will change the surface conditions in terms of elastic constants and stiffness and more importantly, the gradient of such properties along the thickness. This is a typical functionally graded materials (FGM) structure and has been studied extensively for structural applications under multiple loadings such as thermal and electromagnetic fields in recent years. For acoustic wave resonators, such studies are equally important and the wave propagation in FGM structures can be used in the evaluation and assessment of performance, reliability, and life of sensors based on acoustic waves such as the quartz crystal microbalances (QCM). Now we studied the thickness-shear vibrations of FGM plates with properties of AT-cut quartz crystal varying along the thickness in a general pattern represented by a trigonometric function with both sine and cosine functions of the thickness coordinate. The solutions are obtained by using Fourier expansion of the plate deformation. We also obtained the frequency changes of the fundamental and overtone modes which are strongly coupled for the evaluation of resonator structures with property variation or design to take advantages of FGM in novel applications.

cond-mat.mtrl-sci↗

arXiv2014

Thickness-shear Frequencies of an Infinite Quartz Plate with Material Property Variation Along the Thickness

Properties of the quartz crystal blank of a resonator is assumed homogeneous, uniform, and perfect in design, manufacturing, and applications. As end products, quartz crystal resonators are frequently exposed to gases and liquids which can cause surface damage and internal degradation of blanks under increasingly hostile conditions. The combination of service conditions and manufacturing process including chemical etching and polishing can inevitably modify the surface of quartz crystal blanks with changes of material properties, raising the question of what will happen to vibrations of quartz crystal resonators of thickness-shear type if such modifications to blanks are to be evaluated for sensitive applications. Such questions have been encountered in other materials and structures with property variations either on purpose or as the effect of environmental or natural processes commonly referred to as functionally graded materials, or FGMs. Analyses have been done in applications as part of studies on FGMs in structural as well as in acoustic wave device applications. A procedure based on series solutions has been developed in the evaluation of frequency changes and features in an infinite quartz crystal plate of AT-cut with the symmetric material variation pattern given in a cosine function with the findings that the vibration modes are now closely coupled. These results can be used in the evaluation of surface damage and corrosion of quartz crystal blanks of resonators in sensor applications or development of new structures of resonators.

cond-mat.mtrl-sci↗