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Thursday, February 4, 2016

3D micromanipulation at low numerical aperture with a single light beam: the focused-Bessel trap

Yareni A. Ayala, Alejandro V. Arzola, and Karen Volke-Sepúlveda

Full-three-dimensional (3D) manipulation of individual glass beads with radii in the range of 2–8 μm is experimentally demonstrated by using a single Bessel light beam focused through a low-numerical-aperture lens (NA=0.40). Although we have a weight-assisted trap with the beam propagating upward, we obtain a stable equilibrium position well away from the walls of the sample cell, and we are able to move the particle across the entire cell in three dimensions. A theoretical analysis for the optical field and trapping forces along the lateral and axial directions is presented for the focused-Bessel trap. This trap offers advantages for 3D manipulation, such as an extended working distance, a large field of view, and reduced aberrations.

DOI

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