论文标题
狭窄的相奇异性揭示了声波的旋转角度动量转换
Confined phase singularities reveal the spin-to-orbital angular momentum conversion of sound waves
论文作者
论文摘要
我们确定了一个声学过程，在该过程中，其自旋和轨道形式之间的角动量转化。考虑了在两个不混溶的流体的界面和一个孤立的液滴下传播的evanevencent波之间的相互作用。支持入射波的流体的椭圆运动与简单的自旋角动量状态有关，这是文献中的声波最近引入的。我们从实验上观察到，该磁场主要迫使方向波传输圆形液滴的内部，从而揭示了狭窄的相位奇点的存在。该相的循环（围绕一个奇异点）是其轨道形式的角动量的特征，从而证明了转换机制。这项工作中提出的数值和实验观察对声波的角动量的基本理解以及诸如用辐射力或扭矩，声学传感和成像的粒子操纵等应用具有影响。
We identify an acoustic process in which the conversion of angular momentum between its spin and orbital form takes place. The interaction between an evanescent wave propagating at the interface of two immiscible fluids and an isolated droplet is considered. The elliptical motion of the fluid supporting the incident wave is associated with a simple state of spin angular momentum, a quantity recently introduced for acoustic waves in the literature. We experimentally observe that this field predominantly forces a directional wave transport circling the droplet's interior, revealing the existence of confined phase singularities. The circulation of the phase, around a singular point, is characteristic of angular momentum in its orbital form, thereby demonstrating the conversion mechanism. The numerical and experimental observations presented in this work have implications for the fundamental understanding of the angular momentum of acoustic waves, and for applications such as particle manipulation with radiation forces or torques, acoustic sensing and imaging.
