Wave is one of the important carriers of information transmission and plays an important role in the application of information and communication technology. The exploration of the physical characteristics and transmission characteristics of the information wave field can guide the research and development of new information transmission technologies. In recent years, topological phase transition and boundary state transmission based on acoustic systems have attracted people's research interest. Compared with traditional waveguides, topological boundary states can achieve unidirectional protective transmission of waves, immune defects, and other characteristics, and have higher pseudo-spin degrees of freedom. So it has more advantages in regulating wave transmission. Acoustic metamaterials have high design freedom and many characteristics that natural materials do not have, making them an ideal platform for acoustic topology implementation and testing. The topological boundary state has unique protective effect on the backscattering caused by the disorder. It is an ideal carrier of classical information and has important research significance in the fields of wireless communication, passive sensing, and information processing. By studying the topological boundary states of phononic crystals in two-dimensional/three-dimensional systems and explores how to construct and realize phononic crystals with topological properties, to realize the flexible control of acoustic/elastic waves.

Dr. Chengxin Cai received his Ph.D. degree in electronic science and technology from Xi'an Jiaotong University in 2017. In 2008, he joined the School of Information Science and Engineering, Henan University of Technology. His main research focuses on the fundamental theory and application of acoustic/electromagnetic metamaterials, his research spans terahertz tunable multifunctional information metasurfaces, low-frequency underwater acoustic wave regulation, and low-frequency vibration/noise reduction for sound/elastic waves. He has led 10 projects including a National Natural Science Foundation Youth Project and Henan Provincial Science and Technology Key Projects, published 64 academic papers in Journal of Food Engineering, Results in Physics, IEEE Antennas and Wireless Propagation Letters, IEEE Transactions on Instrumentation and Measurement,et al. Awarded the Third Prize of Henan Provincial Science and Technology Progress and serves as a reviewer for Advanced Functional Materials, JASA, JSV, et al.