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 large (radius $\ge 1$ $\mu$m) solid gold particles in air for more than one hour. Once trapped, particles are held stably, 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. We describe the utility of such to investigate large, metallic, and plasmonic particles for display applications.