Minoru K. Kurosawa

BEGINNING OF ACTUATOR APPLICATIONS OF SURFACE ACOUSTIC WAVE DEVICES 

Abstract
High power density and high vibration velocity are key issues for piezoelectric transducers in actuator applications. Surface acoustic wave devices use crystal piezoelectric materials, which provides excellent performance in generating high intensity acoustic waves. About 30 years ago, we tried to introduce SAW transducers into vibration actuators for friction drive motors, atomizers, and gyro-sensors. However, the problem was that at frequencies higher than 10 MHz, only small vibration amplitudes of less than 10 nanometers could be obtained. For friction drive motors such as ultrasonic motors, the smaller the vibration amplitude the more important the contact condition become. To solve the contact problem, high contact pressure conditions were considered at the slider contact area. With the specially designed slider, the SAW motor operated normally. Intermittent power supply was applied to the SAW atomizer in order to operate at a high vibration velocity with moderate average input power. The high frequency operation of tens MHz produced a much smaller particle mists than typical ultrasonic atomizers operating at several tens of kHz. At same time, we tried newly designed SAW gyro sensor, we could not get signals. Later, however, several groups succeeded in obtaining signals.

Bio
Minoru Kurosawa (formerly Kuribayashi) received the B.Eng. degree in electrical and electronic engineering, and the M. Eng. and D. Eng. degrees from Tokyo Institute of Technology, in 1982, 1984, and 1990, respectively. He started the research on ultrasonic motors using bulk PZT in 1983. He became a research associate of the Precision and Intelligence Laboratory, Tokyo Institute of Technology in 1984. In 1992, he became an associate professor at the Department of Precision Machinery Engineering, The University of Tokyo, where he started research on SAW motors and atomizers, piezo film deposition and actuators, and 1bit signal processing. In 1999, he returned to Tokyo Institute of Technology. He has been working on SAW motors, ultrasonic motors, piezo films, 1bit digital signal processing and its application. Currently, he is interested in audio engineering, and his research on distortion of passive components such as resisters, capacitors, coils, and cables for high-fidelity audio systems.

Zhixiong Gong

ACOUSTIC MANIPULATION OF MICROPARTICLES AND MICROFLUIDICS: STRUCTURED VORTEX BEAM INCIDENCE 

Abstract
Acoustic micromanipulation is induced by the acoustic radiation force and/or acoustic streaming from the sound field to the target and surrounding medium. The physical mechanisms are mainly attributed to the fact that the acoustic momenta are transferred to the microparticles or microfluidics by acoustic scattering and absorption. In this talk, we will present some theories on the general acoustic radiation force and the source term of bulk streaming with nonlinear propagation in a three-dimensional free field. Structured vortex beams are categorized into the cylindrical type for the pulling force as a tractor beam and the focused type for the selective trapping. Some challenges and ongoing work of these single-beam acoustical tweezers will be briefly discussed.

Bio
Zhixiong Gong has been an associate professor with the AcousticsX group from the State Key Laboratory of Ocean Engineering at Shanghai Jiao Tong University since 2022. Before he returned to China, He was a visiting scholar in the Physical acoustics group led by Prof. Philip L. Marston at Washington State University in the United States, and then worked as a postdoc with Profs. Michael Baudoin and Jean-Louis Thomas at CNRS UMR8520 IEMN in France. His research interests lie in the interdisciplinary subjects of physical acoustics, acoustofludics, and ocean acoustics. He has been awarded the National Natural Science Fund for Excellent Young Scientists Fund Program (Overseas), the Xiaomi Scholar of the Year 2023, and the Shanghai Jiao Tong University 2030 Initiative in 2024.
https://en.naoce.sjtu.edu.cn/teachers/GongZhixiong.html

Birgit Stiller

LIGHT-SOUND INTERACTIONS FOR OPTICAL NEURAL NETWORKS AND QUANTUM TECHNOLOGIES

Abstract
In this presentation, we will unveil some cutting-edge recent advancements in acoustic micro-actuators. First, we will demonstrate that GHz actuators not only uniquely enable the synthesis of microjets at speeds of up to meters per second, but also that these speeds could be reached in microseconds, leading to phenomenal accelerations in the mega-g range. Second, we will reveal our latest developments in IDT-based selective manipulation, including 3D trapping and displacement, precise rotation control, and high-resolution patterning. These advancements herald a new era of versatility and control in micro-actuation technology, opening doors to a myriad of transformative applications in micro-robotics, biomedicine, and beyond.

Bio
Birgit Stiller is a full professor at Leibniz University Hannover and a Max-Planck-Research Group Leader at the Max Planck Institute for the Science of Light in Erlangen. She is an experimental physicist and her expertise ranges from nonlinear to quantum optics, fiber optics to integrated photonics and applications to optical neural networks and quantum technologies. Before that she was a postdoctoral researcher at The University of Sydney in Australia working in integrated photonics. She completed her PhD at the CNRS Institute FEMTO-ST in Besançon in France on the topic of photonic crystal fibers, followed by a postdoctoral stay in quantum cryptography at the Max Planck Institute for the Science of Light.
www.optoacoustics.de/

Chuyi Chen

HARNESSING ACOUSTOFLUIDICS FOR BIOMEDICAL ADVANCEMENTS

Abstract
Biochips represent a frontier in biomedical technology, harnessing the interdisciplinary strengths to significantly enhance rapid testing and drug development capabilities. Within this realm, acoustofluidics has emerged as a groundbreaking field, merging sophisticated acoustic techniques with micro and nano-scale fluid mechanics to drive innovations in biomedical research. In this presentation, the speaker will outline her contributions to the development of acoustofluidic-based biochips, showcasing their broad application in addressing various biomedical challenges. She will detail the creation of high-purity methods for isolating biomarkers such as exosomes and the engineering of biocompatible platforms for precise manipulation of model organisms, tailored for drug screening applications. Our devices, capable of manipulating objects across seven orders of magnitude—from nanometers to centimeters—demonstrate exceptional versatility, precision, and biocompatibility. These qualities highlight the transformative potential of acoustofluidic devices in converting technological innovations into significant biological and medical breakthroughs. This talk will underscore these achievements, illustrating their profound impact on the field and their promising future applications.

Bio
Dr. Chuyi Chen received her Ph.D. degree in Mechanical Engineering and Materials Science at Duke University, M.S. and B.S. degree in acoustics from Nanjing University.  Prior to joining NC State, Dr. Chen was a Postdoctoral Fellow in the Koch Institute for Integrative Cancer Research at the Massachusetts Institute of Technology. She is the recipient of the Ludwig Center Postdoctoral Fellowship. Dr. Chen has published over 20 articles in journals such as Nature Materials, Nature Communications, Science Advances, PNAS, ACS Nano, and Lab on a Chip. Her research focuses on acoustics, acoustofluidics, micro/nano systems, sensing, and imaging with applications in healthcare, biology, materials, and manufacturing.
https://mae.ncsu.edu/people/chuyi-chen/
https://www.chuyichen.net

Philipp Schulmeyer

SURFACE ACOUSTIC WAVE SENSORS FOR ICE DETECTION AND THICKNESS MEASUREMENT ON WIND TURBINE ROTOR BLADES

(Winner of the 2024 W. Terence Coakley Award)

Abstract
Icing on wind turbine blades increases mechanical wear, reduces power output, and causes significant economic losses. Integrating standardized ice detection systems remains challenging due to the harsh rotor environment, and existing solutions often fail to measure ice thickness accurately. Surface Acoustic Wave (SAW) sensors offer a promising alternative, being small, retrofittable, and capable of passive wireless operation. This presentation introduces novel SAW-based concepts for ice detection, enabling discrete measurements of ice layer thickness on an industry-relevant scale. A key focus is the consideration of realistic, application-specific boundary conditions to facilitate technology transfer. Full-scale field tests on wind turbines play a crucial role in validating this approach.

Valdemar Frederiksen, Henrik Bruus

METAMATERIAL-BASED ACOUSTOFLUIDICS FOR NANOPARTICLE FOCUSING

Abstract
The conventional acoustic focusing of microparticles in acoustic pressure nodes fails for nanoparticles, because the streaming-induced Stokes drag, that swirls particles around, dominate over the acoustic radiation force that focuses particles with diameters less than 2 µm.  Suppressing the acoustic streaming by using inhomogeneous liquids or shape-optimized devices, or altering it to consist of a single centered vortex, may lead to successful nanoparticle focusing. However, the throughput is low due to the smallness of the resulting acoustic radiation force, which is controlled by the typical mid-sized quality factors 100 - 1000 in these devices. In this numerical simulation study, we present a new strategy for acoustic focusing of suspended nanoparticles: By embedding a liquid-filled acoustofluidic channel in a metamaterial, whose coarse-grained elastic moduli are matched to the acoustic properties of the liquid, the acoustic streaming can be suppressed while simultaneously enhance the quality factor of the cavity at selected acoustic resonance modes by 2 to 3 orders of magnitude relative to a comparable conventional device.