Spin and orbital angular momenta of acoustic beams
arXiv:1901.08962 · doi:10.1103/PhysRevB.99.174310
Abstract
We analyze spin and orbital angular momenta in monochromatic acoustic wave fields in a homogeneous medium. Despite being purely longitudinal (curl-free), inhomogeneous acoustic waves generically possess nonzero spin angular momentum density caused by the local rotation of the vector velocity field. We show that the integral spin of a localized acoustic wave vanishes in agreement with the spin-0 nature of longitudinal phonons. We also show that the helicity or chirality density vanishes identically in acoustic fields. As an example, we consider nonparaxial acoustic Bessel beams carrying well-defined integer orbital angular momentum, as well as nonzero local spin density, with both transverse and longitudinal components. We describe the nontrivial polarization structure in acoustic Bessel beams and indicate a number of observable phenomena, such as nonzero energy density and purely-circular transverse polarization in the center of the first-order vortex beams.
15 pages, 3 figures, 1 table, to appear in Phys. Rev. B
References in corpus (12)
- Chiral Quantum Optics
- Quantum spin Hall effect of light
- Chiral nanophotonic waveguide interface based on spin-orbit coupling of light
- Valley Vortex States in Sonic Crystals
- Angular Momenta and Spin-Orbit Interaction of Nonparaxial Light in Free Space
- Measuring the Transverse Spin Density of Light
- Transverse spin and momentum in two-wave interference
- Optical Momentum, Spin, and Angular Momentum in Dispersive Media
- Conservation of the spin and orbital angular momenta in electromagnetism
- Transverse spin and surface waves in acoustic metamaterials
- Polarization Transport of Transverse Acoustic Waves: Berry Phase and Spin Hall Effect of Phonons
- The ubiquitous photonic wheel
Cited by in corpus (34)
- Spatiotemporal Vortex Pulses: Angular Momenta and Spin-Orbit Interaction
- Roadmap on structured waves
- Water-Wave Vortices and Skyrmions
- Observation of polarization singularities and topological textures in sound waves
- Orbital angular momentum of optical, acoustic, and quantum-mechanical spatiotemporal vortex pulses
- Field-theory spin and momentum in water waves
- Spin-orbit interactions of transverse sound
- Elastic Valley Spin Controlled Chiral Coupling in Topological Valley Phononic Crystals
- Symmetry-protected photonic chiral spin textures by spin-orbit coupling
- Generation of Spatiotemporal Vortex Pulses by Simple Diffractive Grating
- Elastic Spin and Orbital Angular Momenta
- Acoustokinetics: Crafting force landscapes from sound waves
- Nonlinear interaction of acoustic waves with a spheroidal particle: radiation force and torque effects
- Polarization singularities and Möbius strips in sound and water-surface waves
- Dynamic Magnetoelastic Boundary Conditions and the Pumping of Phonons
- Momentum, angular momentum, and spin of waves in an isotropic collisionless plasma
- Spin/momentum properties of the paraxial optical beams
- From Elastic Spin to Phonon Spin: Symmetry and Fundamental Relations
- Confined phase singularities reveal the spin-to-orbital angular momentum conversion of sound waves
- Multifunctional acoustic holography based on compact acoustic geometric-phase meta-array
- Babinet-Complementary Structures for Implementation of Pseudospin-Polarized Waveguides
- Generation of twisted magnons via spin-to-orbital angular momentum conversion
- Acoustic circular dichroism in a three-dimensional chiral metamaterial
- Acoustic spin and orbital angular momentum using evanescent Bessel beams
- Spin-orbit interaction in nanofiber-based Brillouin scattering
- Momentum, spin, and orbital angular momentum of electromagnetic, acoustic, and water waves
- Radiation forces and torques in optics and acoustics
- Acoustic helical dichroism in a one-dimensional lattice of chiral resonators
- Imaging the transverse spin density of light via electromagnetically induced transparency
- Symmetry-driven Phononic Metamaterials
- Imaginary spin-orbital coupling in parity-time symmetric systems with momentum-dependent gain and loss
- Spacetime geometry of acoustics and electromagnetism
- Extraordinary transverse spin: Hidden vorticity of the energy flow and momentum distributions in propagating light fields
- Elastic Orbital Angular Momentum