Abstract

In this work, we present a number of near-field optics devices that we have developed and tested for trapping particles ranging in size from 30 nm to a few micron. In the first system, an ultrathin optical fiber is used to trap micron-sized particles in the evanescent field. By milling the ultrathin fiber using a focused ion beam, we can form a slot in which we can trap silica particles of 200 nm diameter. An alternative system we have developed relies on an array of nano-apertures or nano-disks in a thin gold film. Using this plasmonic optical tweezers, we have trapped particles as small as 30 nm using powers as low as 0.4 mW at 980 nm. These traps allow us to study topics as diverse as orbital angular momentum propagation through ultrathin fibers to optical binding.

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