0000000000928740
AUTHOR
G. Millot
Nonlinear pulse propagation in microstructured fibers
International audience
Study of Collisional Effects on Band Shapes of the v1/2v2 Fermi Dyad in CO2 Gas with Stimulated Raman-Spectroscopy .1. Rotational and Vibrational-Relaxation in the 2v2 Band
0021-9606
Measurements of Collisional Line Widths in the Stimulated Raman Q-Branch of the v1 Band of Silane
0377-0486; Self-broadened widths of 28SiH4 in the v1 Q-branch have been measured at room temperature (295 K) using high-resolution stimulated Raman spectroscopy. These collisional widths have been obtained by fitting a superposition of Voigt profiles to the experimental spectra in the pressure range 28-154 Torr. No evidence for line mixing within the tetrahedral components of a Q(J) line has been found. The line broadening coefficients for J up to 13 depend weakly on the rotational quantum number. The mean value is 103.7 x 10(-3) cm-1 atm-1.
Wavelengths Measurements of Continuous Wave Lasers with a Wavemeter - Applications to High-Resolution Raman-Spectra Calibration
0150-536X
Study of Rotational Relaxation Fitting Laws from Calculation of SRS N2 Q-Branch
0301-0104
Accurate Spectroscopic Constants of Nitrogen Determined from Stimulated Raman Spectra of the Fundamental and 1st Hot Bands
0377-0486; Nitrogen specta of the Q-branch of the fundamental and the first hot bands were recorded with a high-resolution stimulated Raman spectrometer at atmospheric pressure and ca. 1300 K. The absolute frequencies of the Raman lines were measured with high accuracy, leading to a refinement of spectroscopic constants. A temperature estimation was also performed from the Raman intensities.
Collisional Line Broadening and Line Shifting in N2-CO2 Mixture Studied by Inverse Raman-Spectroscopy
0301-0104
Propagation autosimilaire et similariton optique
National audience
Collisional shifting and broadening coefficients for the rovibrational anisotropic lines of the v1/2v2 Fermi dyad in CO2 gas studied by stimulated Raman spectroscopy
0377-0486; High-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 lin…
Ondes scélérates optiques
International audience; Nous montrons que les systèmes fibrés présentent des caractéristiques remarquables pour la génération et le contrôle d'impulsions rares et intenses similaires aux vagues scélérates océaniques. En particulier, l'amplificateur Raman faiblement dispersif pompé par une onde incohérente a permis de mettre en évidence l'apparition d'ondes scélérates optiques. Un bon accord théorie - expérience est observé.
Collisional Broadening, Line Shifting, and Line Mixing in the Stimulated Raman 2-v2 Q-Branch of CH4
0021-9606; Self-, argon-, and helium-broadening coefficients have been measured for 13 lines in the 2v2 Raman Q branch of CH4 using stimulated inverse Raman spectroscopy. The linewidths clearly show the symmetry-state dependence characteristic of pressure broadening, and inelastic processes in general, involving spherical-top molecules. Pressure-induced line shifts have also been measured for these features in pure methane. The pressure-shift coefficients do not display the symmetry-state dependence found for the linewidths. By applying the Rosenkranz perturbation treatment to a pair of collisionally mixed lines, we have been able to obtain an estimate of individual state-to-state contribut…
Soliton-based optical communication systems: basic concepts and new trends
International audience
Dunham Coefficients of 14N2 from CARS Measurements of High Vibrational-States in a Low-Pressure Discharge
0377-0486
Raman Intensities of the ν1/ν3 Dyad of 28SiH4
0022-2852; The stimulated Raman spectrum of 28SiH4 has been recorded in the ν1/ν3 region between 2182 and 2190 cm(-1). The intensities of the Raman transitions were modeled using a dyad scheme for the two interacting bands with a first-order polarizability expansion. The involved polarizability parameter; have been adjusted to fit about 800 measured intensities of transitions reaching upper states up to J = 18. The resulting standard deviation is about 10%. (C) 1994 Academic Press, Inc.
Mélange à quatre photons dans les fibres optiques micro-structurées à haute biréfringence
National audience
Rotational Relaxation of Nitrogen in Ternary Mixtures N2-CO2-H2O - Consequences in Coherent Anti-Stokes-Raman Spectroscopy Thermometry
0021-9606; The influence of CO2 and H2O on the rotational relaxation processes of N2 in ternary mixtures N2-CO2-H2O is investigated. The efficiency of these perturbers is responsible for significant modifications of the state-to-state relaxation rates and broadening coefficients. Flame data are well reproduced by taking into account these modifications. The role of these minor species in the determination of temperatures in premixed flames is analyzed. The present relaxation model allows us to understand why the discrepancy between observed and calculated coherent anti-Stokes Raman spectroscopy (CARS) spectra in flames is sometimes resolved by empirically adding a dephasing component to pur…
Modulation de phase croisée lors de la collision de similaritons optiques
National audience; Nous étudions théoriquement et expérimentalement les effets intervenant lors de la collision de similaritons optiques dans un amplificateur Raman à dispersion normale. L'évolution temporelle du profil d'intensité montre l'apparition dans la zone de recouvrement d'une modulation sinusoïdale dont la fréquence diminue linéairement lors de la collision. L'analyse du spectre des impulsions met en évidence les effets de modulation de phase croisée qui interviennent lors de la collision. Néanmoins, après la collision, les similaritons retrouvent globalement leur forme parabolique caractéristique.
Exploitation de l'autoglissement frequentiel soliton limite par des radiations de cherenkov pour generer deux impulsions au decalage frequentiel ou temporel continument ajustable
National audience; Nous exploitons l'apparition de radiations de Cherenkov qui limitent l'autoglissement fréquentiel d'une impulsion soliton pour proposer une source de deux impulsions ultrabrèves dont, suivant l'énergie initiale, il est possible de contrôler de manière continue soit l'écart fréquentiel, soit l'écart temporel.
Enhancement of Sensitivity in High-Resolution Stimulated Raman-Spectroscopy of Gases - Application to the 2v2 (1285 cm-1) Band of CO2
0377-0486