FIG. 7.
Ratio of maximum lateral acoustic force FAx to sphere weight in a 10-W vortex beam versus the ratio of sphere diameter to beam width η. Theoretical lines connect a few discrete values calculated for discrete values of M and therefore discrete beam widths for a specific sphere diameter and composition. Theoretical lines are also truncated where there was no lateral acoustic radiation force as the sphere was too large. Regardless of the sphere material, the most efficient trapping occurred at η close to 1.