1,894 research outputs found
Detection of Spiral photons in Quantum Optics
We show that a new type of photon detector, sensitive to the gradients of
electromagnetic fields, should be a useful tool to characterize the quantum
properties of spatially-dependent optical fields. As a simple detector of such
a kind, we propose using magnetic dipole or electric quadrupole transitions in
atoms or molecules and apply it to the detection of spiral photons in
Laguerre-Gauss (LG) beams. We show that LG beams are not true hollow beams, due
to the presence of magnetic fields and gradients of electric fields on beam
axis. This approach paves the way to an analysis at the quantum level of the
spatial structure and angular momentum properties of singular light beams.Comment: 5 pages, 4 figure
Delayed coupling of logistic maps
We study the synchronization of logistic maps in a one-way coupling configuration. The master system is coupled to the slave system with a delay n1, and the slave is a delayed logistic map with a delay n2. We show that when the slave system has no delay (n2=0), perfectly synchronized solutions exist for strong enough coupling. In these solutions the slave variable y is retarded with respect to the master variable x with a retardation equal to the delay of the coupling [y(i+n1)=x(i)]. When n2Âż0, a regime of generalized synchronization is observed, where y(i+n1) is synchronized with x(i), but not completely, since the master and the slave systems obey different maps. We introduced a similarity function as an indicator of the degree of synchronization and, using a noisy master source, distinguished synchronization from noise-induced correlations.Peer ReviewedPostprint (published version
MAPPING OF FOCUSED LAGUERRE-GAUSS BEAMS: THE INTERPLAY BETWEEN SPIN AND ORBITAL ANGULAR MOMENTUM AND ITS DEPENDENCE ON DETECTOR CHARACTERISTICS
accepted for publication (april 18, 2012) in Physicial Review AInternational audienceWe show that propagating optical fields bearing an axial symmetry are not truly hollow in spite of a null electric field on-axis. The result, obtained by general arguments based upon the vectorial nature of electromagnetic fields, is of particular significance in the situation of an extreme focusing, when the paraxial approximation no longer holds. The rapid spatial variations of fields with a "complicated" spatial structure are extensively analyzed in the general case and for a Laguerre-Gauss beam 2 as well, notably for beams bearing a |l| = 2 orbital angular momentum for which a magnetic field and a gradient of the electric field are present on-axis. We thus analyze the behavior of a atomic size light-detector, sensitive as well to quadrupole electric transitions and to magnetic dipole transitions, and apply it to the case of Laguerre-Gauss beam. We detail how the mapping of such a beam depends on the nature and on the specific orientation of the detector. We show also that the interplay of mixing of polarization and topological charge, respectively associated to spin and orbital momentum when the paraxial approximation holds, modifies the apparent size of the beam in the focal plane. This even leads to a breaking of the cylindrical symmetry in the case of a linearly polarized transverse electric field
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