Application of flat-top focus to 2D trapping of large particles

Hao Chen, K. C. Toussaint

Research output: Contribution to journalArticlepeer-review


The 2D optical trapping ability of larger-than average-particles is compared for three different beam types: a flat-top, a Gaussian beam, and a donut shaped beam. Optical force-displacement curves are calculated in four different size regimes of particle diameters (1.5-20 μm). We find that the trapping efficiency increases linearly with ratio of particle diameter to wavelength for all three beams. As the ratio reaches a specific threshold value, the flat-top focus exhibits the largest trapping efficiency compared to the other two beam types. We experimentally demonstrate that flat-top focusing provides the largest transverse trapping efficiency for particles as large as 20 μm in diameter for our given experimental conditions. The overall trend in our experimental results follows that observed in our simulation model. The results from this study could facilitate light manipulation of large particles.

Original languageEnglish (US)
Pages (from-to)6653-6660
Number of pages8
JournalOptics Express
Issue number6
StatePublished - 2014

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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