Fully-structured counter-propagating optical trap sculpted by spherical aberration

Aberrations of light are commonly known as undesired effects in different applications, including optical trapping. However, here we demonstrate how to take advantage of controlled spherical aberration in order to shape extended optical trapping landscapes, fully-structured in three-dimensional (3D) space and embedding transverse as well as longitudinal electric field contributions. We numerically analyze the light field customization by the simple means of including glass plates in a counter-propagating trapping configuration, presenting sculpted intensity as well as 3D polarization ellipse structures. Experimentally, we prove the realized counter-propagating optical structure by particle velocimetry as well as the analysis of scattered light of optically guided micro-particles. Finally, we demonstrate the potential of our approach by creating extended 3D particle assemblies.