Acoustic tweezers are gaining increasing attention due to their excellent biological compatibility. Recently, the concept of topology has been expanded from condensed matter physics into acoustics, giving rise to a robust wave manipulation against defects and sharp turns. So far, topological acoustics have not been experimentally realized in on-chip level which can be worked as tweezers for microparticle manipulations. Here, we achieved a topological on-chip acoustic tweezer based on the topologically protected phononic mode. This tweezer consisted of one-dimensional arrays of Helmholtz resonant air cavities. Strong microfluidic oscillations induced by acoustic waves were experimentally observed at water-air surfaces of Helmholtz resonant air cavities at the topological interface. Acoustic radiation force induced by these microfluidic oscillations captured microparticles whose sizes were up to 20 um and made them do orbital rotations. Our topological on-chip acoustic tweezer realized non-contact label-free microparticle manipulations in microfluidics and exhibited enormous application potential in the biomedical field.
Implementation of two-dimensional selective acoustic tweezers merely using four straight interdigitated transducers:a numerical proof of concept of radiation field synthesis by pulsed acoustic waves
Holographic acoustical tweezers (HAT) based on Archimedes-Fermat spiraling InterDigitated Transducers (S-IDTs) are a versatile tool for the selective manipulation of microparticles [Baudoin et. al., Sci. Adv., 5: eaav1967 (2019)] and cells [Baudoin et. al., Nat. Commu., 11, 4244 (2020)] in a standard microfluidic environment. These binary active holograms produce some focused helical wave, with the ability to trap particles at the vortex core. Yet, all the studies conducted with S-IDTs have so far been restricted to 2D manipulation only. Here we show (i) that 3D radiation trap for microparticl…
Acoustical tweezers open major prospects in microbiology for cells and microorganisms contactless manipulation, organization and mechanical properties testing since they are biocompatible, label-free and can exert forces several orders of magnitude larger than their optical counterpart at equivalent wave power. Yet, these tremendous perspectives have so far been hindered by the absence of selectivity of existing acoustical tweezers -- i.e., the ability to select and move objects individually -- and/or their limited resolution restricting their use to large particle manipulation only. Here, we …
Optical levitation of dielectric particles in vacuum is a powerful technique for precision measurements, testing fundamental physics, and quantum information science. Conventional optical tweezers require bulky optical components for trapping and detection. Here we design and fabricate an ultrathin dielectric metalens with a high numerical aperture of 0.88 at 1064 nm in vacuum. It consists of 500 nm-thick silicon nano-antennas, which are compatible with ultrahigh vacuum. We demonstrate optical levitation of nanoparticles in vacuum with a single metalens. The trapping frequency can be tuned by …
We investigate the prospects for micron-scale acoustic wave components and circuits on chip in solid planar structures that do not require suspension. We leverage evanescent guiding of acoustic waves by high slowness contrast materials readily available in silicon complementary metal-oxide semiconductor (CMOS) processes. High slowness contrast provides strong confinement of GHz frequency acoustic fields in micron-scale structures. We address the fundamental implications of intrinsic material and radiation losses on operating frequency, bandwidth, device size and as a result practicality of mul…
EPFL（洛桑联邦理工学院）；Vienna University of Technology (TU Wien)（维也纳工业大学）；Univ. Bordeaux, CNRS, Bordeaux INP, I2M（波尔多大学）；Arts et Metiers Institute of Technology（巴黎高科国立高等工艺学院）
The manipulation of acoustic waves plays an important role in a wide range of applications. Currently, acoustic wave manipulation typically relies on either acoustic metasurfaces or phased array transducers. The elements of metasurfaces are designed and optimized for a target frequency, which thus limits their bandwidth. Phased array transducers, suffering from high-cost and complex control circuits, are usually limited by the array size and the filling ratio of the control units. In this work, we introduce active coding piezoelectric metasurfaces; demonstrate commonly implemented acoustic wav…
Topological mechanical metamaterials translate condensed matter phenomena, like non-reciprocity and robustness to defects, into classical platforms. At small scales, topological nanoelectromechanical metamaterials (NEMM) can enable the realization of on-chip acoustic components, like unidirectional waveguides and compact delay-lines for mobile devices. Here, we report the experimental realization of NEMM phononic topological insulators, consisting of two-dimensional arrays of free-standing silicon nitride (SiN) nanomembranes that operate at high frequencies (10-20 MHz). We experimentally demon…
Manipulating micro-scale object plays paramount roles in a wide range of fundamental researches and applications. At micro-scale, various methods have been developed in the past decades, including optical, electric, magnetic, aerodynamic and acoustic methods. However, these non-contact forces are susceptible to external disturbance, and so finding a way to make micro-scale object manipulation immune to external perturbations is challenging and remains elusive. Here we demonstrate a method based on new trapping mechanism to manipulate micro-scale object in a gas flow at ambient conditions. We f…
Acoustic waves have emerged as versatile on-chip information carriers with applications ranging from microwave filters to transducers. Nonreciprocal devices are desirable for the control and routing of high-frequency phonons. This is challenging, however, due to the linear response of most acoustic systems. Here, we leverage the strong piezoelectricity of lithium niobate to demonstrate fully tunable gain, loss, and nonlinearity for surface acoustic waves using electric circuitry. This allows the construction of a nonlinear acoustic parity-time-symmetric system and enables nonreciprocal transmi…
Wireless communication through dynamic spectrum allocation over microwave bands, essential to accommodate exponentially growing data traffic, requires massive array of radio-frequency (RF) filters for adaptive signal shaping at arbitrary frequencies. However, conventional RF filters based on planar acoustic resonators are incapable to realize such massive integrated arrays, due to their large footprint and limited on-chip frequency scalability. Here, we present a signal processor enabled by integration of three-dimensional ferroelectric-gate fin (FGF) nano-acoustic resonators with extreme freq…
Experimental Realization of Topological Surface Acoustic Wave Resonances under Surface Liquid Loading for Micro-volume sample Sensings
Ningbo University（宁波大学）；Zhejiang-Italy Joint Lab for Smart Materials and Advanced Structures, School of Mechanics and Engineering Science, Ningbo University（宁波大学力学与工程科学系中意智能材料与先进结构联合实验室）；Key Laboratory of Impact and Safety Engineering, Ministry of Education, Ningbo University（宁波大学教育部冲击与安全工程重点实验室）
The combination of microfluidic technology and optical fluids characterization techniques has been recently applied to produce lab-on-a-chip systems. In the present work, bringing together the imaging technique called photoacoustic imaging (PAI) and microfluidic technology were implemented to obtain micro-scale imaging. Laser-induced ultrasound signals were measured from microdroplets produced in a simple T-junction microfluidic system. Single pulse laser images were produced as a result of the combination of the aforementioned techniques, allowing to obtain of geometrical information of the m…
Routing and guiding acoustic waves around sharp corners without backscattering losses is of great interest in the acoustics community. Sonic crystals have been primarily utilized to design backscattering-immune waveguides. While conventional approaches use defects to guide waves, a considerably more sophisticated and robust approach was recently developed based on topological edge states. In this paper, we propose a radically different theoretical framework based on extremely anisotropic metamaterials for engineering backscattering-immune waveguides. We theoretically derived the exact conditio…
Topological Skyrmion-type microparticle manipulation based on surface acoustic wave phase modulations
Zhejiang-Italy Joint Lab for Smart Materials and Advanced Structures, School of Mechanics and Engineering Science, Ningbo University（宁波大学力学与工程科学系智能材料与先进结构中意联合实验室）
Using a previously well-tested numerical model, we demonstrate theoretically that good acoustophoresis can be obtained in a microchannel embedded in an acoustically soft, all-polymer chip, by excitation of whole-system ultrasound resonances. In contrast to conventional techniques based on a standing bulk acoustic wave inside a liquid-filled microchannel embedded in an elastic, acoustically hard material, such as glass or silicon, the proposed whole-system resonance does not need a high acoustic contrast between the liquid and surrounding solid. Instead, it relies on the very high acoustic cont…
