This value is obtained shortly before and after the 2-mode experiment to allow direct comparison by keeping all other experimental conditions unchanged. Beyond that, the bubble gets destroyed. The thick dotted lines denote unstable bubble behaviour. The open circles show the maximum SL intensity achieved. The dashed line is the maximal photo current for pure sine wave driving.
H is the enthalpy of the liquid.
First, we calculated the driving sound signal that would lead to the most violent collapse, indicated by the smallest minimum radius during a bubble oscillation cycle using the above equation. Comparing equal power signals is convenient, because the power stays constant upon phase changes, making it possible to compare numerics and experiments. 2 shows the driving pressure and the bubble response of different driving signals. A strong increase in the maximum radius can be seen already by adding just the second harmonic to a sine wave. The numerically computed optimal phase difference is and the individual amplitudes are bar and bar.