Near-field optical forces arise from evanescent electromagnetic fields and can be advantageously used for on-chip
optical trapping. In this work, we investigate how evanescent fields at the surface of photonic cavities can efficiently trap
micro-objects such as polystyrene particles and bacteria. We study first the influence of trapped particle’s size on the
trapping potential and introduce an original optofluidic near-field optical microscopy technique. Then we analyze the
rotational motion of trapped clusters of microparticles and investigate their possible use as microfluidic micro-tools such
as integrated micro-flow vane. Eventually, we demonstrate efficient on-chip optical trapping of various kinds of bacteria.
In this work, we demonstrate an original single-nanoparticle deposition process based on near-field optical forces
arising from much localized plasmonic resonant gap-mode. At first, nanoparticles exclusively made of fluorescent dye
molecules are fabricated in aqueous colloidal suspension. Near-field optical forces are then used to attract and deposit
single nanoparticles in the nanogap of plasmonic nanoantennas. This one-step deposition process allows targeted
deposition of nanoscale materials directly from a colloidal dispersion to a few-nanometer large area of interest.