Propagation characteristics of controllable dark-hollow beams in a quadratic-index medium.

In this paper, the propagation of controllable dark-hollow beams (CDHBs) passing through a quadratic-index medium is studied. An analytical expression for the propagation of CDHBs in a quadratic-index medium is presented based on the ABCD matrix method, and the effect of the beam parameters on the evolution of a CDHB is investigated. It is found that the intensity distribution of CDHBs evolves periodically during propagation in the quadratic-index medium. The results indicate that the distance in which the dark-hollow center of a CDHB disappears can be increased by the beam parameters.