Affiliation:
1. Sharif University of Technology
Abstract
Optical tweezers are proven and indispensable micro-manipulation tools.
It is very common to use an immersion-assisted high NA objective for
optical trapping of micrometer-sized beads. However, such objectives
suffer from low working depth range. Here we show, both by theory and
experiment, that a dry objective can be utilized for optimal trapping
of even sub-micrometer objects. For the first time, to the best of our
knowledge, we were able to stably trap polystyrene beads with radii of
270 and 175 nm in 3D using an objective with numerical aperture
of 0.9.
Subject
Atomic and Molecular Physics, and Optics,Statistical and Nonlinear Physics