Optimisation de la conversion Raman par accord de vitesse de groupe induit par lumière lente

International audienc

Cancellation of Raman pulse walk-off by slow light

International audienceWe theoretically demonstrate in a nonlinear optical fiber system with a narrowband Raman gain that pulse walk-off between the pump and the Raman Stokes waves can be fully compensated for by Raman slow light, leading to group-velocity matching between the interacting waves, greater useful interaction length, and thereby enhanced Raman amplification efficiency. Limitations due to Kerr effect are further discusse

Cancellation of pulse walk-off in Raman amplifiers via slow light

International audienc

All-optical tunable pulse frequency chirp via slow light

International audienceWe theoretically investigate slow light via stimulated Raman scattering, paying special attention to the picosecond regime where chromatic dispersion and cross-phase modulation must be considered. In addition to the control of the Raman pulse walk-off, we demonstrate that the cross-phase-modulation-induced frequency chirp can also be all-optically tuned via Raman slow light. We further demonstrate that this new implication is a consequence of the fact that the group velocity is significantly more affected than the phase velocity in slow-light media

Pressure broadening, shift, and interference effect for a multiplet line in the rovibrational anisotropic stimulated raman spectrum of molecular oxygen

0022-2852High-resolution stimulated inverse Raman spectroscopy has been applied to the study of collisional broadening, shifting, and line mixing for the O-o(J, N = 5) triplet line of the fundamental vibrational band of molecular oxygen. Accurate line broadening coefficients for the individual J components within the triplet have been measured for the first time and show a significant J dependence. The line broadening coefficients are larger than those previously obtained for unresolved pure rotational Raman lines. The additional broadening is expected to result from electronic spin relaxation. The pressure-induced line shift has been obtained for this Line and compared to the value obtained for the fundamental Q branch. By applying the Rosenkranz perturbation treatment to the collisionally mixed components of the triplet line, we have been able to obtain an estimate of the coupling parameters. (C) 1996 Academic Press, Inc

Collisional shifting and broadening coefficients for the rovibrational anisotropic S(J) lines of nitrogen studied by inverse Raman spectroscopy

0377-0486Line shifting and broadening coefficients of the anisotropic S(J) lines (v = 0, J --> v = 1, J + 2) of the nitrogen molecule were measured at room temperature using high-resolution stimulated Raman spectroscopy. A rotational quantum number dependence of the S(J) line shifts was observed. In order to avoid an asymmetry of experimental origin, a suitable theoretical profile was fitted to the experimental lineshapes. This study allows the testing of the theoretical methods for calculating the line broadening coefficients in anisotropic Raman scattering, which have already been used in the analysis of infrared absorption data. The behaviour of the modified sum rule and the RPA (random phase approximation) methods was studied

Collisional shifting and broadening coefficients for the rovibrational anisotropic lines of the v1/2v2 Fermi dyad in CO2 gas studied by stimulated Raman spectroscopy

0377-0486High-resolution stimulated Raman spectroscopy was applied to the study of collisional broadening and shifting for rovibrational anisotropic Raman Lines of the Fermi dyad of molecular carbon dioxide, The O(J) lines of the v1 band and the S(J) lines of the 2v2 band were recorded at 295 K. The pressure-induced line shifts were obtained and compared with the overall shift of the high-density Raman Q-branch, A rotational quantum number dependence of the rovibrational line broadening coefficients was observed. The experimental line broadening coefficients were used in order to check the ability of two theoretical methods (random phase approximation and sum rule) for calculating the line broadening coefficients in anisotropic Raman scattering. (C) 1998 John Wiley & Sons, Ltd

Fitting and scaling laws for high temperature Q branch collapse in the O2 stimulated Raman spectra in O2-H2O mixtures

0021-960

Collisions between vector and scalar spatial solitons

International audienc

Induced symmetry-breaking and polarization switching of spatial soliton through vector collision

International audienc