EXPERIMENTAL OBSERVATION OF FLUIDLIKE MOTION OF OPTICAL VORTICES

We have observed the fluidlike rotation of a pair of identical optical vortices (OV’s) as they propagate through free space. Similar to vortex filaments in a fluid, the initial rotation rate is found to be inversely proportional to the squared distance of separation. Owing to unusually small vortex cores, we obtained rotation rates that were 2 orders of magnitude larger than expected for “conventional” large core OV’s. [S0031-9007(97)04388-3]