A new twist on light: applications of the optical vortex soliton

An optical vortex appears as a black circular spot surrounded by bright illumination in the transverse cross-section of a light beam. This phenomenon is attributed to the phase of the beam, which twists like a spiral stair-case, along the optical axis. In fact, this field is a well known mode in both waveguide and scattering theory, and is given in cylindrical coordinates. As will be shown, there are simple methods of producing such linear waves. In self-defocusing nonlinear refractive media, the refractive index is greatest where the intensity is zero, e. g., in the center of an optical vortex