1,721,164 research outputs found
Resonantly absorbing one-dimensional photonic crystals
No full textA compact theoretical description of the effects of dissipation on the propagation of light waves through a
multilayer periodic mirror built from resonant absorbing atoms is presented. Depending on the lattice periodicity,
ultranarrow photonic gaps, weak polaritonic gaps, as well as rather atypical gap structures may be
observed. Because of the atom’s absorption line shape Bloch gap modes may acquire quite a cumbersome
structure which is thoroughly studied here or which may even disappear when dissipation becomes sufficiently
strong. The same approach well applies also to resonantly absorbing photonic crystals based on excitonic
resonances
Two-photon transitions to excited states in atomic hydrogen
No full textResonant two-photon transition rates from the ground state of atomic hydrogen to ns excited states have been computed as a function of photon frequencies in the length and velocity gauges in order to test the accuracy of the calculation and to discuss the rate of convergence over the intermediate states. The dramatic structure of the transition rates produced by intermediate-state resonances is exhibited. A two-photon transparency is found in correspondence to each resonance. © 1982 The American Physical Society
Modelli esplicativi e tendenze di ricerca sulle differenze psicologiche tra maschi e femmine
No full textElectromagnetic induced tranparency in bulk and microcavity semiconductors
No full textWe discuss our recent results on electromagnetically induced transparency (EIT) effects based on intrinsic free exciton and biexciton states in semiconductors. The Lambda configuration obtained from the IS and 2P yellow exciton levels of Cu2O leads to a well-developed EIT regime, akin to the atomic case. The coherent driving of the exciton-biexciton transition in CuCl induces a tunable transparency window within the polaritonic stop-band, due to the presence of a third polariton branch in the dressed system. In a microcavity configuration, this gives rise to three reflectivity dips in the strong coupling regime
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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