Dynamics of Optical Vortices in Speckle Patterns with Sub-Nanometric Spectral Resolution

By exploiting a novel quantitative imaging technique based on Synthetic Optical Holography, we describe the dynamic behaviour of optical vortices in a speckle pattern generated by the interference of random scattered waves from the rough surface of a glass substrate. The system combines the advantages of digital holography and low-coherence interferometry to retrieve multiple holograms with sub-nanometric spectral resolution. The collection of multiple images of the complex scattered field allows to provide a statistical characterization of the phase singularities by changing the exciting wavelength.