Acoustic radiation force on cylindrical particles near subwavelength slits

We theoretically and experimentally investigate the acoustic radiation force (ARF) on cylindrical steel particle near subwavelength slits. By using finite-difference-time-domain (FDTD) method combined with momentum-flux tensor, the dependence of the ARF on the frequency, width of slit are analyzed, respectively. It is predicted that the particle near the slit surface could suffer a trapping effect when the resonance of the slit occurs. This trapping effect is also observed in experiment.