1,721,166 research outputs found
Gain saturation and output power of distributed feedback lasers
No full textA study is made of distributed feedback lasers operating above threshold. A set of non-linear differential equations governing the field distribution is obtained. Some properties of these equations are discussed analytically. Then the results of some numerical calculations are presented. As a result, it is shown that the field distribution inside the laser deviates notably from the linear case. Some explanations of what the analysis means in physical terms and how the different operating regimes are characterized are provided
Second harmonic generation as a tool for measuring mode coupling, pulse length and mode size in short laser pulses
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High-Power electron-beam pre-ionised CO2 cw laser modelling I : Description of the investigated device and numerical calculations on e-beam ionization
No full textPart I of the paper - devoted to modelling high-power CW lasers - gives a brief description of the investigated device and uses an analvtical approximation to Bethe’s formula to calculate the following quantities: the space profiles in the discharge chamber of the electron beam energy, the stopping power and the source term under operating conditions for four-component mixtures of practical interest. The energy loss of the primarv beam in travelling through a thin Al foil is calculated. Parts II and III will be published promptly. Part II will be devoted to the plasma characteristics in the discharge chamber and to the kinetic and fluid-dynamic model of the laser. Part III will be devoted to an assessment of the numerical results obtained from the model and their comparison with experimental data
Fabry-Perot Resonators with Oscillating Mirrors for Long Baseline Interferometers used as Detectors of Gravitational Waves
No full textStatus of Virgo
No full textIn this paper, we present the status of the VIRGO interferometer, the French–
Italian gravitational wave detector. During the last two years the construction
of the apparatus has been completed. At the same time, the commissioning
of the detector central part, the VIRGO central interferometer, has been used
to test all the technical solutions and in particular the most original part: the
seismic isolation system. In the next few months the commissioning of the
whole detector will start with the alignment and the locking of one of the two
3 km long Fabry–Perot cavities
Detection of ionized Hydrogen in resonant multiphoton ionisation of benzene in the visible.
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Experimental analysis of the presence of ionized atomic Hydrogen in resonant MPI of benzene in the visible
No full textModello di laser a CO2 di grande potenza
No full textSi presenta il modello numerico unidimensionale di un laser continuo a CO2 d’alta potenza con preionizzazione a fascio elettronico. Il codice simula il comportamento di una miscela di He:N2:CO2:CO in rapido flusso (≈100 m/s) in un condotto in cui viene addotta energia tramite scarica elettrica e prodotti elettroni secondari per mezzo di un fascio di elettroni energetici (≈60 keV). La densità degli elettroni prodotti nella camera di scarica è valutata facendo uso della teoria di Bethe secondo la formulazione di Rorhlich e Carlson. La densità degli elettroni della scarica elettrica è calcolata nella ipotesi di neutralità di carica locale tenendo conto dei processi di perdita per ricombinazione ione-elettrone ed attaccamento elettrone-molecola. La cinetica vibrazionale è descritta tramite un set di rate-equations che tengono conto della variazione, lungo la direzione di flusso della miscela, dell’energia immagazzinata in ciascun modo di vibrazione. L’insieme di equazioni cinetiche è accoppiato tramite l’equazione dell’entalpia al set di equazioni fluidodinamiche. Si presentano alcuni risultati forniti dal codice numerico quali ad esempio il coefficiente di guadagno per piccolo segnale, il flusso di saturazione, etc., e si confrontano con i dati sperimentali disponibili
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