Statistical properties analysis of dynamic speckles produced by a rotating cylindrical surface

Dynamic speckles appear when a rotating cylindrical object with the angular velocity ω was illuminated by a Gaussian light beam. Speckle pattern on the observation screen changes continuously with object rotating, which is a random process. The statistical properties of dynamic speckles produced in the Fresnel diffraction field by the rotating cylindrical object considered to be a weak phase screen are investigated in detail. The parameters describing the properties of the space-time cross-correlation of dynamic speckles are given under some special conditions, as spatial correlation length, correlation time, translation distance and correlation distance. These parameters show that the statistical properties of dynamic speckles depend on optical conditions, surface roughness, curvature radius and angular velocity of the rotating object as well as geometry structure of optical setup. The motion forms of dynamic speckles are analyzed based on these parameters. From that one can find that the boiling motion of dynamic speckles depends on the distance between the object plane and the observation plane, the wave-front-curvature radius of the beam at the object plane, and the radius of object.