Simulating Acoustic Orientation Trapping for Stable Levitation

Acoustic levitation permits non-contact handling of mm-scale samples. To improve its applicability, we did a simulation study to optimize orientation control of a sample residing in a phased array levitator. The acoustic forces and torques on asymmetric samples in asymmetric traps were determined by solving the acoustic scattering problem with the boundary element method. The angular stiffness of the trap was mapped as a function of the field shape. This allowed us to choose the optimal incidence field for different shaped samples. A mathematical model was created that predicts the results with good agreement.