Study of efficient sonochemical reaction by focused ultrasound

Efficient methods of inducing sonochemical reactions with focused ultrasound produced with phased array transducers are described. One method uses periodic switching between clockwise and counterclockwise spiral focal fields, and the other uses superimposition of the second harmonic wave. Sonochemically induced oxidation of iodide ion was used to evaluate the efficiency of these methods. The first method exhibited about ten times higher oxidation rate at the optimum switching period (3 ms) than the conventional CW insonation. The second can drastically decrease the ultrasound intensity threshold for the sonochemical reaction and exhibited an even higher reaction rate than the first method