2024/01/09 by Andrew Kille, Andrei Afanasev, Kille, Andrew +1 · 2 citations
Engineering · #Advanced Antenna and Metasurface Technologies #Classical Physics (physics.class-ph) #FOS: Physical sciences #Material Properties and Processing #Other Condensed Matter (cond-mat.other) #RFID technology advancements
paper · pdf · doi:10.48550/arxiv.2402.00873
openalex publication_date 2024/01/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this work, we examine the extraordinary behavior of polarization and spin angular momentum (AM) density in the vicinity of longitudinal field zeros in three-dimensional monochromatic acoustic fields. We demonstrate that, as governed by the continuity equation, the velocity fields of arbitrary acoustic sources maintain non-diffractive elliptical polarization structures that enclose longitudinal field zeros, despite having divergent transverse spatial profiles of intensity. Furthermore, embedded in these nonparaxial field contours, for infinite distance, are threads of circular polarization singularities. We illuminate these inherent properties in acoustic vortex fields, dipole arrays, and the famous Young's double slit experiment. Our results reveal novel characteristics of vector sound waves that provide a platform for future studies and applications of structured acoustic waves and chiral acoustic phenomena.