Optical trapping of large metallic particles in air

In this paper, we introduce a horizontally oriented photophoretic "boat" trap that is capable of capturing and self-loading the largest reported (radius >= 1 mu m) photophoreticaly trapped solid gold particles in air for more than 1 h. Once trapped, particles are held stably, without hopping, even as the trap is modified to scan axially or expanded to a larger size to increase the capture cross section. We theoretically present and experimentally demonstrate each of these affordances.