Reverse propagation of femtosecond pulses in optical fibers

We present a numerical technique for reversing femtosecond pulse propagation in an optical fiber, such that given any output pulse it is possible to obtain the input pulse shape by numerically undoing all dispersion and nonlinear effects. The technique is tested against experimental results, and it is shown that it can be used for fiber output pulse optimization in both the anomalous and normal dispersion regimes

Il flusso inverso. Un primo inquadramento geografico degli italiani di ritorno

The Reverse Flow: A First Geographical Overview of Returning Italians. By historical tradition, the emigration of compatriots is a structural phenomenon. However, as the number of expatriates increases over the last fifteen years, an objectively new fact becomes increasingly evident: a progressive growth of repatriations. Starting from an examination of the geographical literature on the subject, this contribution presents an initial geographical reflection on the areas of origin and the places of new residence of Italians who have returned in recent years, disaggregating the available statistical data (registry entries from abroad of Italian citizens made available by ISTAT and AIRE data provided by the Ministry of the Interior) at a provincial level

Feasibility experiments on time-resolved fluorosensing applied to oil slicks

The introduction of time resolved observations can provide a very penetrating tool in the practice of laser fluorosensing. The investigations have demonstrated a relevance of multispectral, time resolved analysis for oil fingerprinting. By comparative studies on a variety of crude oils and their most significant fractions, it was found that the process of time decay in a composite oil is characterized by a few steps, which are associated with specific components in the medium light range. The average decay times of these pure fractions are markedly differentiated as to absolute values and spectral spread; as a consequence, the corresponding parameters in the resultant crude are quite sensitive to the particular mixture of these components. Measurements of the time response give then a finer discrimination between oil classes, depending on the relative content of certain fractions. Experiments were pursued with an improved fluorosensor facility, in order to test the application of time resolved fluorosensing to remote samples on water

Continuous-wave spontaneous lasing in mercury pumped by resonant two-photon absorption

The first continuous-wave two-photon absorption laser-induced stimulated emission (CTALISE) is demonstrated. The 7^1S-6^1P transition in mercury at 1014nm wavelength is used and selective lasing of different isotopes is observed.Comment: 3 pages, 5 figure