Versatile and scalable fabrication method for laser-generated focused ultrasound transducers

E. Aytac-Kipergil, E. J. Alles, H. C. Pauw, J. Karia, S. Noimark, A. E. Desjardins
2019 Optics Letters  
A versatile and scalable fabrication method for laser-generated focused ultrasound transducers is proposed. The method is based on stamping a coated negative mold onto polydimethylsiloxane, and it can be adapted to include different optical absorbers that are directly transferred or synthesized in situ. Transducers with a range of sizes down to 3 mm in diameter are presented, incorporating two carbonaceous (multiwalled carbon nanoparticles and candle soot nanoparticles) and one plasmonic (gold
more » ... anoparticles) optically absorbing component. The fabricated transducers operate at central frequencies in the vicinity of 10 MHz with bandwidths in the range of 15-20 MHz. A transducer with a diameter of 5 mm was found to generate a positive peak pressure greater than 35 MPa in the focal zone with a tight focal spot of 150 μm in lateral width. Ultrasound cavitation on the tip of an optical fiber was demonstrated in water for a transducer with a diameter as small as 3 mm.
doi:10.1364/ol.44.006005 pmid:32628218 fatcat:2pc54lydh5d4bcd6thw3bykg3m