STANDING-WAVE ACOUSTIC TRAP FOR NONINTRUSIVE POSITIONING OF MICROPARTICLES

A nonintrusive three-dimensional trap for microscopic particles in a Liquid is described. The trap is based on acoustic radiation forces in an ultrasonic confocal standing-wave cavity. Experiments at 11 MHz demonstrate the concept and verify the theoretically calculated forces. Theoretical calculations for higher-frequency systems indicate a significant potential for low-rms-displacement trapping of submicrometer particles, making the trap suitable for nonintrusive scanning near-field optical microscopy. (C) 1995 American Institute of Physics.