Self-alignment of photonic wires by optical forces


Laser light may have significant mechanical effects on microscopic objects. We have theoretically demonstrated that a silicon photonic wire that is broken by a gap and an offset may tend to self-align by the forces generated by the very light it guides. The two parts of the silicon wire, each of cross-section dimensions of a few hundred nanometers, tend to bend to form a continuous wire. Conversely, depending on the geometrical parameters, the light flowing inside the waveguides may cause the two parts to deflect away from each other. These novel effects we present may be used for nanoscale machines on a silicon chip. The results suggest the guided light may hold a silicon wire cantilever in stable equilibrium or vibrate it, with application in sensing of nanoscale objects.