On May 16, 2026, as part of the signature lecture series “NanGaoShi·Physics Salon” organized by the School of Physics and Technology, Professor Zheng Xu, a tenured professor and doctoral supervisor at Tongji University, delivered an academic lecture titled “Research on Nondiffracting Beam Generation Based on Pure Phase Information” to faculty members and students at Nanjing Normal University. Faculty members in related research areas, together with some graduate and undergraduate students, attended the report session.

During the presentation, Professor Zheng Xu first introduced the basic physical picture and research background of nondiffracting beams. He pointed out that nondiffracting beams can maintain an invariant transverse amplitude distribution during free-space propagation and exhibit self-healing behavior after obstruction. These properties give them important application potential in particle manipulation, high-resolution imaging, long-distance communication, and acoustic field control. Starting from plane-wave propagation characteristics and Huygens' principle, Professor Xu explained the propagation behavior of acoustic beams under finite-aperture conditions and further introduced the generation of Weber and Mathieu beams in more complex geometric coordinate systems.

Subsequently, Professor Xu focused on a method for generating nondiffracting beams based on pure phase information. To address the high computational cost of conventional methods that rely on complicated numerical evaluations of special functions when constructing complex beams, he presented a strategy based on approximate analytical expressions for the target phase distribution. Combined with numerical simulation results, the report demonstrated the effectiveness of this method for generating Weber and Mathieu beams. By comparing amplitude-and-phase modulation with phase-only sources, Professor Xu illustrated the advantages of pure phase modulation in maintaining beam quality, propagation invariance, and self-healing capability. This work provides a concise and practical technical route for the rapid design and engineering implementation of nondiffracting acoustic beams.

The report addressed frontier issues in nondiffracting acoustic beams and integrated theoretical derivation, numerical verification, and application-oriented insights. Following the presentation, Professor Xu engaged in in-depth discussions with faculty members and students present on topics including the experimental implementation of pure phase modulation, phase differences between Weber and Airy beams, parameter selection in complex acoustic field construction, and the potential biomedical applications of ultrasonic effects.

Short Bio of Prof. Zheng Xu:

Professor Zheng Xu is a tenured professor and doctoral supervisor at Tongji University. He received his M.S. degree from Nanjing University in 2009 and his Ph.D. degree from Nagoya University in 2012. He is a recipient of a national-level major young talent program. He has led multiple national, provincial, and ministerial research projects and participated in national key R&D programs. He has published more than 40 papers as first or corresponding author in internationally recognized academic journals, with more than 1,200 citations. His research interests focus on ultrasonic effects and their biomedical applications.