Three-dimensional ultrasonic trapping of micro-particles in water with a simple and compact two-element transducer

Amanda Franklin, Asier Marzo, Robert Malkin, Bruce Drinkwater

Research output: Contribution to journalArticle (Academic Journal)peer-review

37 Citations (Scopus)
371 Downloads (Pure)


We report a simple and compact piezoelectric transducer capable of stably trapping single and multiple micro-particles in water. A 3D-printed Fresnel lens is bonded to a two-element kerfless piezoceramic disk and actuated in a split-piston mode to produce an acoustic radiation force trap that is stable in three-dimensions. Polystyrene micro-particles in the Rayleigh regime (radius λ/14 to λ/7) are trapped at the focus of the lens (F# = 0.4) and manipulated in two-dimensions on an acoustically transparent membrane with a peak trap stiffness of 0.43 mN/m. Clusters of Rayleigh particles are also trapped and manipulated in three-dimensions, suspended in water against gravity. This transducer represents a significant simplification over previous acoustic devices used for micro-particle manipulation in liquids as it operates at relatively low frequency (688 kHz) and only requires a single electrical drive signal. This simplified device has potential for widespread use in applications such as micro-scale manufacturing and handling of cells or drug capsules in biomedical assays.
Original languageEnglish
Article number094101
Number of pages5
JournalApplied Physics Letters
Early online date28 Aug 2017
Publication statusPublished - Aug 2017


  • Transducers
  • Chemical compounds
  • Cell communication
  • Ultrasonics
  • Acoustical measurements


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