Figure 2.

Acoustophoretic separation of microbeads. Graph showing the proportion of 5 μm beads (gray) and 7 μm beads (black) collected in the central outlet, compared to the total number of beads collected, as a function of U², the piezoceramic transducer voltage squared. (U² is linearly proportional to the acoustic energy density and thus also the acoustic velocity of the beads.) Experiments were performed with acoustophoresis pre-alignment (PA) on (filled symbols) or off (open symbols). Measurements were repeated at two of the voltages on a later occasion (filled circles). The lines represent fits of a cumulative distribution function to the experimental data (see Supplementary Note 1). The values given are means, the error bars denoting min and max values (n=3).