  Optical dipole-traps are used in various scientific fields, including
classical optics, quantum optics and biophysics. Here, we propose and implement
a dipole-trap for nanoparticles that is based on focusing from the full solid
angle with a deep parabolic mirror. The key aspect is the generation of a
linear-dipole mode which is predicted to provide a tight trapping potential. We
demonstrate the trapping of rod-shaped nanoparticles and validate the trapping
frequencies to be on the order of the expected ones. The described realization
of an optical trap is applicable for various other kinds of solid-state
targets. The obtained results demonstrate the feasibility of optical
dipole-traps which simultaneously provide high trap stiffness and allow for
efficient interaction of light and matter in free space.
