0000000000273237
AUTHOR
E. Hertz
Experimental investigation of the optical Kerr effect at large laser intensity: impact on the propagation of a short and intense laser pulse
Talk given by O. Faucher; International audience
Higher-order Kerr terms allow ionization-free filamentation in gases
Talk given by J. Kasparian; International audience; Higher-order nonlinear indices, rather than plasma, provide the main defocusing contribution to filamentation in gases at 800 nm. Developing generalized Miller formulae, we discuss the generality of this as a function of the laser wavelength
Stratégies de contrôle pour la manipulation spatiale de molécules
Talk given by E. Hertz; National audience
Observation d'effets Kerr d'ordres élevés (HOKE) dans les gaz
Talk given by O. Faucher; National audience
Alignement moléculaire sous impulsions laser ultracourtes
Talk given by O. Faucher; National audience
Higher-order Kerr terms allow ionization-free filamentation in gases
International audience; We show that higher-order nonlinear indices (n4 , n6 , n8 , n10) provide the main defocusing contribution to self-channeling of ultrashort laser pulses in air and Argon at 800 nm, in contrast with the previously accepted mechanism of filamentation where plasma was considered as the dominant defocusing process. Their consideration allows to reproduce experimentally observed intensities and plasma densities in self-guided filaments.
Mesure de l'effet Kerr d'ordre élevé des constituants de l'air
Talk given by V. Loriot
Spectral phase reconstruction of femtosecond laser pulse from interferometric autocorrelation and evolutionary algorithm
International audience; We report on the complete temporal characterization of femtosecond laser pulses from second-order interferometric autocorrelation and laser spectrum measurements. The method exploits a newly developed autocorrelator based on a two photon-absorption signal produced directly within a camera sensor so as to provide a single-shot interferometric autocorrelation of great reliability and robustness. Interferometric autocorrelation trace and laser spectrum are exploited for a spectral phase retrieval via an evolutionary algorithm. The quality of the reconstruction for highly modulated spectral phases imprinted by a pulse shaper confirms the reliability of the method. The au…
Laser induced field-free molecular alignment
Talk given by O. Faucher; International audience
Negative and positive Kerr nonlinearity of air calibrated with transient molecular alignment
Talk given by O. Faucher; International audience; Nonlinear electronic Kerr index of the major air constituents has been measured up to high order terms using transient molecular alignment as a reference. Sign reversal associated to negative nonlinearity is observed above a pulse intensity of 26 TW/cm^.2
TIGER: TIme-Gated Electric field Reconstruction
We present a novel self-referenced method for the complete temporal characterization (phase and amplitude) of ultrashort optical laser pulses. The technique, called TIme-Gated Electric field Reconstruction (TIGER), measures a second-order nonlinear signal (namely, second harmonic generation or two-photon absorption) produced by four time-delayed replicas of the input pulse. The delays are spatially encoded in the beam profile using a four-faced pyramid-like optical element. The presented technique enables single shot measurement and does not require any spectral measurements, in contrast with well-known self-referenced characterization methods. Depending on the chosen geometry, the recorded…
High-order Kerr nonlinearity of air calibrated with transient molecular alignment
Talk given by O. Faucher; International audience; Nonlinear electronic Kerr index of the major air constituents has been measured up to high order terms using transient molecular alignment as a reference. Sign reversal associated to negative nonlinearity is observed above a pulse intensity of 26 TW/cm^2.