Polarization singularities and Möbius strips in sound and water-surface waves

Abstract

We show that polarization singularities, generic for any complex vector field but so far mostly studied for electromagnetic fields, appear naturally in inhomogeneous yet monochromatic sound and water-surface (e.g., gravity or capillary) wave fields in fluids or gases. The vector properties of these waves are described by the velocity or displacement fields characterizing the local oscillatory motion of the medium particles. We consider a number of examples revealing C-points of purely circular polarization and polarization Möbius strips (formed by major axes of polarization ellipses) around the C-points in sound and gravity wave fields. Our results (i) offer a new readily accessible platform for studies of polarization singularities and topological features of complex vector wavefields and (ii) can play an important role in characterizing vector (e.g., dipole) wave-matter interactions in acoustics and fluid mechanics.

arXiv comment9 pages, 5 figures, to appear in Phys. Fluids

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Cited by in corpus (8)

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• Generation of Spatiotemporal Vortex Pulses by Simple Diffractive Grating
• Topological near fields generated by topological structures
• Confined phase singularities reveal the spin-to-orbital angular momentum conversion of sound waves
• Babinet-Complementary Structures for Implementation of Pseudospin-Polarized Waveguides
• Electric-Magnetic Geometric Phase