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Bondani M.,CNR Institute for Photonics and Nanotechnologies | Allevi A.,University Dellinsubria And Cnism | Andreoni A.,University Dellinsubria And Cnism
European Physical Journal: Special Topics | Year: 2012

We present what is to our knowledge the first experimental implementation of a ghost imaging protocol based on an intense multimode spontaneous parametric down-conversion process, that is a PDC starting from vacuum. Temporal and spatial properties of the quantum field used in the protocol are also discussed. © 2012 EDP Sciences and Springer. Source

Iskhakov T.,Max Planck Institute for the Science of Light | Allevi A.,University Dellinsubria And Cnism | Kalashnikov D.A.,Agency for Science, Technology and Research Singapore | Sala V.G.,University Pierre and Marie Curie | And 4 more authors.
European Physical Journal: Special Topics | Year: 2011

We demonstrate measurement of normalized Glauber's intensity correlation functions of different orders using an array photodetector. As the light source, we use a laser beam scattered by a rotating ground-glass disc, which has statistics close to that of thermal light. We compare the measurements of the normalized correlation functions to that of the difference-intensity variance and show that they are in a certain sense complementary. The independence of the variance measurement on the number of temporal modes has been demonstrated for the first time. Different versions of high-order ghost imaging are also realized and characterized quantitatively. © 2011 EDP Sciences and Springer. Source

Stromqvist J.,KTH Royal Institute of Technology | Nardo L.,University Dellinsubria And Cnism | Broekmans O.,VU University Amsterdam | Kohn J.,University of Fribourg | And 8 more authors.
European Physical Journal: Special Topics | Year: 2011

The Biotin-Streptavidin complex is a widely studied system in biology and biophysics, because of its extremely strong non-covalent binding affinity. The latter is often exploited to link molecules to substrates or to one another. However, the details of the Biotin-Streptavidin binding have not been fully elucidated so far. Particularly, the role of cooperative effects in enhancing the binding affinity has not been clarified. Our long-term aim is to investigate this point by implementing two complementary approaches, fluorescence correlation spectroscopy and time-correlated single-photon counting. As both methods rely on the analysis of fluorescence signals, biotin labeled with Atto-550-dye was used. In this work, in order to get a first overview of the system, we analyzed solutions in three paradigmatic ranges of Biotin-to-Streptavidin concentration ratio. Fluorescence correlation spectroscopy measurements allowed us to extract diffusion times of free biotin and of biotin-Streptavidin complexes, and also to gain information about the dynamics of the intersystem crossing between the first excited triplet and the first excited singlet states. Time-correlated single-photon counting made it possible to derive the lifetimes of the different species in solution, as well as to deduce relevant information about the relative abundance of Streptavidin-complexed and free Biotin. © 2011 EDP Sciences and Springer. Source

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