Self-Trapping of Optical Beams: Spatial Solitons

Although people have always been fascinated by visual manifestations of nonlinear wave phenomena, such as tsunamis and tidal waves, the first scientifically documented report of a self-trapped wave did not come until 1834, when a Scottish scientist, John S. Russell, observed a “rounded smooth and well defined heap of water” propagating in a narrow and shallow canal “without change of form or diminution of speed.” The water was calm on both sides of this unusual wave, and Russell noted that it had the form of a “solitary elevation.”