Fig. 6.
Measurement of the dependence of the acoustic force on on the excitation frequency for a 5.8 μm diameter polystyrene bead in water. These data are valid for a probe chamber with 0.62 mm fluid layer thickness, the other probe chamber dimensions are given in table 1. The optically trapped bead was placed 400 μm above the bottom, and the driving voltage of the ultrasound transducer was 3Vp–p. Also shown are the results of our model calculations (dashed line). We scaled the calculated force such that the peak value for the most prominent resonance at 2380 kHz matches the observed data.