Acoustic radiation force on a rigid sphere exerted by a Gaussian pulsed wave

Area of Science:

• Acoustics
• Wave Physics
• Particle Manipulation

Background:

• Acoustic radiation force (ARF) is crucial for particle manipulation.
• Most ARF studies use steady-state fields, limiting transient pulse investigations.
• Transient ARF offers superior selectivity and spatial tuning with simpler hardware.

Purpose of the Study:

• To develop a unified theory for transient acoustic radiation force on arbitrary-sized objects.
• To provide a closed-form solution for pulse-parameter-dependent transient forces.
• To extend transient ARF theory beyond the Rayleigh scattering limit.

Main Methods:

• Derivation of a unified transient ARF theory from scattering theory.
• Development of a closed-form solution for transient forces.
• Analysis of the coupling between pulse spectrum and object scattering response.

Main Results:

• The theory recovers exact solutions in the monochromatic limit.
• Transient ARF arises from the coupling of pulse spectrum and object's frequency-dependent scattering.
• Pulse width and center frequency dictate spectral probing of scattering resonances.
• Observed phenomena include parameter-dependent saturation, oscillations, and strength hierarchies.

Conclusions:

• The presented theory provides a predictive tool for pulsed acoustic tweezers.
• It breaks the Rayleigh scattering limit for transient ARF.
• Opens new avenues for pulsed wave-particle interactions and applications.