Topologically crafted spatiotemporal vortices in acoustics.

Area of Science:

• Acoustics
• Wave Physics
• Metamaterials

Background:

• Wave vortices, characterized by phase singularities and topological charges, are fundamental in classical and quantum physics.
• Optical spatiotemporal vortex states, with phase singularities in both space and time, have recently been explored.
• Vortex beams have diverse applications in optics and other scientific domains.

Purpose of the Study:

• To report the topologically robust generation of acoustic spatiotemporal vortex pulses.
• To demonstrate the use of an acoustic meta-grating with broken mirror symmetry for this purpose.
• To explore the potential applications of these acoustic vortices.

Main Methods:

• Utilizing an acoustic meta-grating with broken mirror symmetry.
• Inducing a topological phase transition within the meta-grating.
• Observing the emergence of phase singularities with opposite topological charges in the momentum-frequency domain.

Main Results:

• Successfully generated topologically robust acoustic spatiotemporal vortex pulses.
• Demonstrated that the generated vortices are resilient to structural perturbations of the meta-grating.
• Confirmed the emergence of a pair of phase singularities with opposite topological charges.

Conclusions:

• The developed acoustic meta-grating enables robust generation of spatiotemporal vortex pulses.
• These acoustic vortices hold promise for advanced studies and applications in acoustics.
• This work opens new avenues for exploring spatiotemporal structured waves in various wave systems.