Investigation on the radius of a hemispherical microlens of an optical fiber end for three-dimensional trapping

We studied the optical forces acting on a sphere in order to corroborate the three-dimensional optical trapping by the laser beams from optical fiber ends inserted at an angle. From these investigations, we verified that there was only one stable point of equilibrium located below the beam-crossing point. Furthermore, we could reveal that employing microlenses in a dual-beam trap enhanced the trapping stability and increased the trapping volume.