Singularity distribution of the dynamic speckles in the nano-magnetic fluid interferometry

The optical vortex distribution of the dynamic speckles in the interferometry and the corresponding variation characteristics were obtained by Fourier transform with Laguerre-Gaussian filter. The change of dynamic speckle caused by the movement of the nano-magnetic particles is the same as appearing in the change of the singular distribution. And when the nanometer magnetic particles moved in the gathered process into dispered process, the dynamic speckle singularity distribution illustrated that there were two variations of the vortex density, to begin with from big to small, and to end with from small to big that corresponded to the magnetic liquid movement. The optical vortex density is big corresponding smaller spot speckles and the magnetic fluid in the steady moving. The optical vortex density is little corresponding to the larger spot speckles and the magnetic fluid in the intensely moving. Research results indicate the existence of the relation between the movement of the nano-magnetic particles and the variations of the singular distribution.