Emission of Acoustic Point Sources near an Interface

The emission of point sources is a cornerstone of wave-based physics, underpinning applications in optics and acoustics. While optical theories for point sources near interfaces are well established, a unified acoustic framework, modeled after its optical counterpart to provide cohesive insights into emission behaviors, remains underdeveloped. In this Letter, we extend the optical framework to acoustics, focusing on point sources near solid-fluid interfaces. Our theory predicts far-field patterns with richer features than their optical analogs, including multiple peaks and nonmonotonic supercritical emission dependence on source depth. For circularly polarized sources, we uncover depth-dependent transverse spin angular momentum in leaky Rayleigh waves, revealing opposite directions for distinct peaks. These findings shed new light on polarization related phenomena in acoustic near fields, bridging optics and acoustics while advancing the understanding of wave-matter interactions.