We present an approximate analysis of the nonlinear operation of the hollow-waveguide laser with Gaussian reflectivity profile output mirror, including gain saturation and longitudinal- as well as transverse-field distribution of the laser mode. The model presented is general and can be applied to the study of an arbitrary configuration of the waveguide laser. In particular, the laser characteristics show the influence of the position of the output mirror and the Gaussian mirror parameter on the power efficiency of the laser system. It was shown that optimal position of the output mirror, which provides maximal power efficiency (with other parameters constant), depends on output power level and the mirror reflectivity coefficient.
A novel method based on two-pulse excitation of a hollow cathode discharge to determine metal atoms diffusion coefficients in noble gases was tested in Cu-He and Cu-Ne systems. The excitation conditions such as time duration of the discharge current pulses and configurations of the hollow cathode discharge were checked. Measurements carried out over the wide range gas pressures allowed obtaining the Cu atoms time-decay curves from which the diffusion coefficients were calculated. The values for Cu atom diffusion coefficients of 570 and 310 cm^2 s^{-1} mbar in He and Ne, respectively were in a good agreement with earlier reported data achieved by using the absorption spectroscopy method. The diffusion coefficient of Cu in ^3He, the lighter isotope of helium, was also found to be 670 cm^2 s^{-1} mbar that agreed well with the kinetic theory of gases. To authors believe this value was not reported previously.
The results of experimental investigations of diffuse (volume) nanosecond elevated-pressure discharges in a non-uniform electric field at a time resolution of a recording system being equal to ≈100 ps are presented in this paper. The application of the runaway electrons preionized diffuse discharge is promising for obtaining high-power radiation pulses in the VUV and UV spectral region.
The paper deals with numerical simulation and theoretical study of injection-locked Fabry-Perot semiconductor laser diodes and their transient and steady-state properties. Motivation for this research comes from the fact that Fabry-Perot semiconductor laser diodes seem to be good candidates for transmitters applied in optical network units of new generation wavelength-division-multiplexed passive optical networks. We base our model on the full scale multimode rate equation system, which comprises all supported longitudinal modes of Fabry-Perot semiconductor laser diode, providing its high reliability and broad applicability. We analyze the influence of bias current and spontaneous emission coupling factor on injection-locking characteristics of Fabry-Perot semiconductor laser diodes and find that injection power of the master laser required to maintain an acceptable side-mode-suppression-ratio strongly depends on these parameters. The emphasis of our investigation is on spontaneous emission coupling factor, since its value is often assumed rather than thoroughly calculated or measured. As we show in the paper, variations of this parameter may affect theoretical results and their comparison with experimental data.
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