Prof. Qiu will present a fundamentally different light micromanipulation scheme which realizes stable trapping and continuous optical pulling force simultaneously, i.e., tractor beam. Moreover, they prove that all light can be tractor beam without using negative-index metamaterial, gain media, or complicated laser configuration. The origin of pulling force by modeling tractor beams and its explicit correlations on laser types, particle's parameters, and beam polarization modulation have been illustrated. Instead of treating the object as a "blackbox" and interfering multiple beams, their technique exploits a single beam with phase modulation, and more importantly the fundamentals of the energy exchange, force direction switching, and far-field radiation flipping. The major criterion is to manipulate the beam-particle interference to maximize the transfer of momentum along the forward direction, so that the reaction force will be dragging the particle all the way towards light source continuously. New schemes of sensing and trapping are to be presented based on plasmonics and a few recent research work will be introduced based on transformation optics.

Free sandwiches will be provided!