Abstract

We report the optimization of two-side sample imaging through two orthogonal objectives and sample manipulation by single-beam optical trapping through one of the objectives. A high numerical aperture objective (NA = 1.0) is used to generate multiple laser traps configured by phase diffractive optical elements implemented on a phase programmable modulator. Supplementary lateral imaging through a NA = 0.55 objective represents a trade-off between the resolution and the field of view that provides additional information about the sample and its environment, impossible to obtain from conventional optical trapping setups where imaging is performed only along the trapping objective axis. The usefulness of two-side imaging combined with optical manipulation is illustrated by three different experiments: multiple beads trapped in 3D arrays, red blood cells rotated by multiple tweezers and manipulation of a glass grain with irregular shape.