Affiliation: | a Central Laboratory of Optical Storage and Processing of Information, Bulgarian Academy of Sciences, P.O. Box 95, 1113, Sofia, Bulgaria b CNR, Department of Chemical Engineering, University of Pisa, I-56100, Pisa, Italy c Department of Solid State Physics, RISØ National Laboratory, DK-4000, Roskilde, Denmark d Optics and Fluid Dynamics Department, RISØ National Laboratory, DK-4000, Roskilde, Denmark |