Search results for "Ultra"
showing 10 items of 4451 documents
Polarization angle dependence of the breathing modes in confined one-dimensional dipolar bosons
2021
Probing the radial collective oscillation of a trapped quantum system is an accurate experimental tool to investigate interactions and dimensionality effects. We consider a fully polarized quasi-one dimensional dipolar quantum gas of bosonic dysprosium atoms in a parabolic trap at zero temperature. We model the dipolar gas with an effective quasi-one dimensional Hamiltonian in the single-mode approximation, and derive the equation of state using a variational approximation based on the Lieb-Liniger gas Bethe Ansatz wavefunction or perturbation theory. We calculate the breathing mode frequencies while varying polarization angles by a sum-rule approach, and find them in good agreement with re…
All-optical extinction-ratio enhancement of a 160 GHz pulse train by a saturable-absorber vertical microcavity
2006
International audience; A vertical-access passive all-optical gate has been used to improve the extinction ratio of a 160 GHz pico-second pulse train at 1555 nm. An extinction ratio enhancement of 6 dB is observed within an 8 nm bandwidth. Such a device is a promising candidate for low-cost all optical reamplication and reshaping (211) regeneration at 160 Gbits/s.
Alignement moléculaire sous impulsions laser ultracourtes
2006
Talk given by O. Faucher; National audience
Higher-order Kerr terms allow ionization-free filamentation in gases
2010
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.
Laser induced field-free molecular alignment
2008
Talk given by O. Faucher; International audience
Field-free molecular alignment of ethylene
2007
Talk given by O. Faucher; International audience
High-order Kerr nonlinearity of air calibrated with transient molecular alignment
2009
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.
La molécule d'éthylène soumise à des impulsions laser femtosecondes : spectroscopie rotationnelle et alignement
2006
Talk given by B. Lavorel
Control and optimization of postpulse molecular alignment by shaped laser pulse
2008
Talk given by O. Faucher; International audience
Laser induced molecular alignment of ethylene
2007
Talk given by O. Faucher