Saturated negative and complementary speckle patterns

Marc Guillon, Neurophotonics laboratory, Paris V University.

We image saturated negatives of speckle patterns thanks to super-resolution
STED microscopy. Zeros of intensity then appear as bright spots centered on
optical vortices. Their topological charge is experimentally determined
from negative patterns playing with polarization, thus allowing the
observation of creation and annihilation processes along the propagation
axis. In addition, the ability of vortices of speckle pattern to confine
fluorescence to sub-diffraction dimensions is demonstrated, paving the way
to novel super-resolution imaging techniques through turbid media. A
microscope scheme based on two complementary speckle patterns, where
intensity maxima and zeros are exchanged, is proposed.