Acoustic aligning of micro-particles by phononic crystal slab

Among various manipulation methods, acoustic manipulation has some advantages including penetrability, non-contact and versatility, without any biochemical decorations to particles. Recently, we have theoretically demonstrated that phononic crystal slab (PCS) can generate periodically gradient field near the surface, which can be used for trapping particles. In this letter, we experimentally realize aligning polystyrene micro-particles by PCS. The PCS we fabricated consists of a stainless steel slab patterned with periodical arrays of rectangular gratings on the downside, and the upside of the plane surface is used for particle manipulation. Since the manipulation system is fabricated on a chip, which can be easily integrated with MEMS technology and combined with other micro-processing technology, we believe this technology can be developed to meet the needs of non-contact and precise manipulation of cells and biological particles.