Manipulation of dielectric particles using photonic crystal cavities

The authors present a theoretical study of the optical trapping forces on dielectric particles occurring in the highly localized evanescent field of planar photonic crystal (PC) cavities. These forces are evaluated by means of finite element simulations for particle sizes ranging from several nanometers to micrometers, and characteristic size-dependent changes of the trapping behavior are found. The authors introduce the phenomenon of self-induced trapping due to the resonance shift of the cavity and propose a transport mechanism based on alternating excitation of different cavity modes. Thus, PC cavities are promising candidates for applications involving the manipulation and arrangement of dielectric particles.