Propagation properties of optical vortices in random speckle field based on Fresnel diffraction scheme

We illustrated the propagation properties of optical vortices in random field based on Fresnel diffraction scheme using computer simulations. Vortex distribution, phase distribution and the zero-crossing lines of the real and imaginary parts of the optical field were analyzed comparatively in two dimensional space perpendicular to z direction. Then, the evolution of optical vortices was studied along propagation direction. And the relation between vortex density and the distance was analyzed. Moreover, the vortex lines were visualized and discussed in a cube of 256×256×256 μm3 with speckle patterns and phase maps of different sections superposed.