Zhongqing Su, Ph.D.
Chair Professor of Intelligent Structures and Systems
Head of Department of Mechanical Engineering
The Hong Kong Polytechnic University
Keynote Title: Femtosecond Laser-enabled Nondestructive Material Characterization: From Induction of Picosecond Surface Acoustic Waves to Imaging of Microchip Anisotropy
Abstract: Path-breaking advances in photostriction have shed new light on optical–acoustic coupling and opened up intriguing application prospects. In this talk, we will report a new nondestructive evaluation framework based on the ultrafast laser ultrasonics, from fundamental theory to implementation details, for precise material characterization of monocrystalline semiconductor wafers which are of a high degree of anisotropy, and for rapid imaging of interior features of stacked micro-systems. The femtosecond-laser-enabled ultrasonics techniques, which are operated in a non-contact manner, offer new possibilities in high-resolution material characterization, making use of the ultrashort acoustic wavelength of laser-generated ultrasound. The developed approach has paved a new way for selectively acquiring the high-sensitivity optoacoustic wave components for high-definition characterization of opaque, structurally complicated semiconductors. In addition, we will also present a fully noncontact, opto-acoustic approach for easy inducing, customizing and manipulating picosecond surface acoustic waves (SAWs) using an ultrafast femtosecond laser. The proposed research will provide a new approach to induce and flexibly steer gigahertz SAWs, to facilitate the ease generation of parameter-adjustable SAWs for applications such as ultrahigh-frequency nondestructive evaluation and acoustofluidics research.
Biography: Prof. Zhongqing Su is the Chair Professor of Intelligent Structures and Systems and Head of the Department of Mechanical Engineering at The Hong Kong Polytechnic University (PolyU). He is the current Editor-in-Chief of the journal Ultrasonics, holds the Changjiang Chair Professorship, and has been the Vice President of the Hong Kong Society of Theoretical and Applied Mechanics since 2023. He is an elected Distinguished Fellow of the International Institute of Acoustics and Vibration. He earned his PhD in 2004 from the School of Aerospace, Mechanical and Mechatronic Engineering at The University of Sydney, Australia, where he also completed his postdoctoral training under the "Australian Research Council – Australian Postdoctoral Fellowship" before he joined PolyU. His research interests span the area of ultrasonics, structural health monitoring (SHM), wave propagation, nondestructive evaluation, smart materials and advanced composites. He was/is the Chair of a number of key international conferences in the field, including the 7th Asia-Pacific Workshop on SHM (Hong Kong, 2018), the SPIE Conference on Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2023 (Long Beach, the United States, 2023), and the SPIE Conference on Health Monitoring of Structural and Biological Systems XVIII (Long Beach, the United States, 2024).