Contactless microparticle control via ultrahigh frequency needle type single beam acoustic tweezers
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Updated: Mar 12, 2026

Utilization of Plasmonic and Photonic Crystal Nanostructures for Enhanced Micro- and Nanoparticle Manipulation
Published on: September 27, 2011
Chunlong Fei, Ying Li1, Benpeng Zhu2
1NIH Resource Center for Medical Ultrasonic Transducer Technology and Department of Biomedical Engineering, University of Southern California , Los Angeles, California 90089, USA.
Abstract:
This paper reports on contactless microparticle manipulation including single-particle controlled trapping, transportation, and patterning via single beam acoustic radiation forces. As the core component of single beam acoustic tweezers, a needle type ultrasonic transducer was designed and fabricated with center frequency higher than 300 MHz and -6 dB fractional bandwidth as large as 64%. The transducer was built for an f-number close to 1.0, and the desired focal depth was achieved by press-focusing technology. Its lateral resolution was measured to be better than 6.7 μm by scanning a 4 μm tungsten wire target. Tightly focused acoustic beam produced by the transducer was shown to be capable of manipulating individual microspheres as small as 3 μm. "USC" patterning with 15 μm microspheres was demonstrated without affecting nearby microspheres. These promising results may expand the applications in biomedical and biophysical research of single beam acoustic tweezers.

