Experimental investigation of multiple-particles pattern by a one-dimensional grating resonance field

Manipulation of particles by ultrasonic waves is a primary technique in the fields of precision manufacturing, materials engineering, in vitro diagnosis, since it can control the motion of objects in the sound field in a contactless and noninvasive manner. In general, the free sound field, such as, the focused field, plane wave, etc., generated by a single transducer can only manipulate a single particle. While the complex field generated by a transducer array should be actuated by complex electric control system, which makes the manipulation device expensive and cumbersome. Thus, modulated acoustic field for particle manipulation is still in demand. Here, we experimental realize a one-dimensional acoustic grating to tune sound fields for parallel pattern of multiple particles. The physical mechanism is that due to the resonance coupling between the periodic diffraction wave on the surface of the acoustic grating and the Fabry-Perot resonant in the acoustic grating slit, inducing a periodical gradient sound field on the surface of the acoustic grating. Then, particles in the periodical gradient sound field can be trapped in two stable positions in one period of the grating. These concepts and realizations of particle patterns in the acoustic grating pave the way for the parallel manipulation of particles in acoustic manipulation technologies.