Strong radiation force induced in two-dimensional photonic crystal slab cavities

Radiation force induced by an electromagnetic field stored in a two-dimensional photonic crystal slab is examined. We considered two different types of photonic crystal cavities, namely, double-layer slab cavity structures and air-slot cavity structures. With double-layer structures, induced force is attractive or repulsive depending on the spatial symmetry of the stored electromagnetic field profile. For air-slot structures, we showed that a horizontal attractive force is induced between slabs, and it could be stronger than that for double-layer structures in the case considered here. The induced force on a photonic crystal slab is so strong that it can be detected experimentally with the microelectromechanical systems technique. A simple physical model based on a coupled-resonator well describes these results.