Ge Hao, Liu Shuai, Xu Xiang-Yuan, Long Zi-Wei, Tian Yuan, Liu Xiao-Ping, Lu Ming-Hui, Chen Yan-Feng
National Laboratory of Solid State Microstructures & Department of Materials Science and Engineering, Nanjing University, Nanjing, Jiangsu 210093, China.
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
Phys Rev Lett. 2023 Jul 7;131(1):014001. doi: 10.1103/PhysRevLett.131.014001.
Recently, the discovery of optical spatiotemporal (ST) vortex beams with transverse orbital angular momentum (OAM) has attracted increasing attention and is expected to extend the research scope and open new opportunities for practical applications of OAM states. The ST vortex beams are also applicable to other physical fields that involve wave phenomena, and here we develop the ST vortex concept in the field of acoustics and report the generation of Bessel-type ST acoustic vortex beams. The ST vortex beams are fully characterized using the scalar approach for the pressure field and the vector approach for the velocity field. We further investigate the transverse spreading effect and construct ST vortex beams with an ellipse-shaped spectrum to reduce the spreading effect. We also experimentally demonstrated the orthogonality relations between ST vortex beams with different charges. Our study successfully demonstrates the versatility of the acoustic system for exploring and discovering spatiotemporally structured waves, inspiring further investigation of exotic wave physics.
最近，具有横向轨道角动量（OAM）的光学时空（ST）涡旋光束的发现引起了越来越多的关注，并有望扩展研究范围，为OAM态的实际应用开辟新机遇。ST涡旋光束也适用于其他涉及波动现象的物理领域，在此我们在声学领域拓展了ST涡旋概念，并报告了贝塞尔型ST声涡旋光束的产生。利用压力场的标量方法和速度场的矢量方法对ST涡旋光束进行了全面表征。我们进一步研究了横向扩展效应，并构建了具有椭圆形频谱的ST涡旋光束以减小扩展效应。我们还通过实验证明了不同电荷的ST涡旋光束之间的正交关系。我们的研究成功展示了声学系统在探索和发现时空结构波方面的多功能性，激发了对奇异波物理的进一步研究。
