showing 30 related works from this author
Tunable source of infrared pulses in gas-filled hollow core capillary
2020
International audience; We report a tunable source that generates pulses in the infrared from an optical parametric amplification in a gas-filled hollow core capillary based on four-wave mixing process, in which the phase matching strongly depends on the gas pressure and the pump. In our case, we have generated pulses from 1 to 1.6 m in the sub-µJ level together with a parametric amplification in the visible.
Interpretation of negative birefringence observed in strong-field optical pump-probe experiments: High-order Kerr and plasma grating effects
2013
The analysis of negative birefringence optically induced in major air components (Loriot et al., [1, 2]) is revisited in light of the recently reported plasma grating-induced phase-shift effect predicted for strong field pump-probe experiments (Wahlstrand and Milchberg, [3]). The nonlinear birefrin- gence induced by a short and intense laser pulse in argon is measured by femtosecond time-resolved polarimetry. The experiments are performed with degenerate colors, where the pump and probe beam share the same spectrum, or with two different colors and non-overlapping spectra. The in- terpretation of the experimental results is substantiated using a numerical 3D+1 model accounting for nonlinear…
Towards CEP stable sub two cycle IR pulse compression with bulk material
2010
We demonstrate both experimentally and numerically that self-steepening during propagation in a hollow-fiber followed by linear propagation through glass in the anomalous dispersion enables pulse compression down to 1.9 cycles at 1.8 micron wavelength.
Experimental investigation of the optical Kerr effect at large laser intensity: impact on the propagation of a short and intense laser pulse
2010
Talk given by O. Faucher; International audience
Higher-order Kerr terms allow ionization-free filamentation in gases
2010
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
Optical kerr effect in the strong field regime
2013
The optical Kerr response of hydrogen atom submitted to a strong and short near infrared laser pulse excitation is studied by solving the full 3D time-dependent Schro¨dinger equation. The nonlinear polarization evaluated at the driving field frequency is compared to the canonical expression derived from perturbation theory. A discrepancy between the two models is observed at large intensity affecting the nonlinear propagation of short and intense laser pulses.
Observation d'effets Kerr d'ordres élevés (HOKE) dans les gaz
2011
Talk given by O. Faucher; National audience
Mid-infrared supercontinuum generation from 2 to 14 μm in various chalcogenide glasses optical fibers
2019
Chalcogenide glasses optical fibers with step index or microstructured profiles are drawn from low toxicity compositions. Supercontinuum generation lead to an infrared spectrum spanning from 2 to 14µm with a 10µm core fiber of 40mm length.
Mechanism of hollow-core-fiber infrared-supercontinuum compression with bulk material
2010
We numerically investigate the pulse compression mechanism in the infrared spectral range based on the successive action of nonlinear pulse propagation in a hollow-core fiber followed by linear propagation through bulk material. We found an excellent agreement of simulated pulse properties with experimental results at 1.8 {mu}m in the two-optical-cycle regime close to the Fourier limit. In particular, the spectral phase asymmetry attributable to self-steepening combined with self-phase modulation is a necessary prerequisite for subsequent compensation by the phase introduced by glass material in the anomalous dispersion regime. The excellent agreement of the model enabled simulating pressur…
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.
Transition from plasma-driven to Kerr-driven laser filamentation.
2011
While filaments are generally interpreted as a dynamic balance between Kerr focusing and plasma defocusing, the role of the higher-order Kerr effect (HOKE) is actively debated as a potentially dominant defocusing contribution to filament stabilization. In a pump-probe experiment supported by numerical simulations, we demonstrate the transition between two distinct filamentation regimes at 800 nm. For long pulses (1.2 ps), the plasma substantially contributes to filamentation, while this contribution vanishes for short pulses (70 fs). These results confirm the occurrence, in adequate conditions, of filamentation driven by the HOKE rather than by plasma.
Filament-induced visible-to-mid-IR supercontinuum in a ZnSe crystal: Towards multi-octave supercontinuum absorption spectroscopy
2016
Abstract We report on the generation of multiple-octave supercontinuum laser source spanning from 0.5 μm to 11 μm induced by multi-filamentation in a ZnSe crystal. The generated supercontinuum is both spatially and spectrally characterized. It is then exploited in a proof-of-principle experiment for methane spectroscopy measurements by means of the supercontinuum absorption spectroscopy technique. The entire absorption spectrum is successfully recorded within the whole spectral bandwidth of the supercontinuum. Experimental results are in fairly good agreement with the HITRAN database, confirming the reliability and stability over several hours of the generated supercontinuum.
Molecular quantum interface for storing and manipulating ultrashort optical vortex
2022
Light beams carrying orbital angular momentum (OAM) have become over the past few years a subject of widespread interest with unprecedented applications in various fields such as optical communication, super-resolution imaging, optical tweezers, or quantum processing. We demonstrate in the present work that gas-phase molecules can be used as a quantum interface to store an OAM carried by an ultrashort laser pulse. The interplay between spin angular momentum and OAM is exploited to encode the spatial phase information of light beams into rotational coherences of molecules. The embedded spatial structure is restored on-demand with a reading beam by taking advantage of field-free molecular ali…
Spectral dependence of purely-Kerr driven filamentation in air and argon
2010
5 pags, 4 figs.-- PACS number(s): 42.65.Jx, 42.65.Tg, 78.20.Ci. -- Publisher error corrected 27 September 2010, Erratum Phys. Rev. A 82, 039905 (2010): https://doi.org/10.1103/PhysRevA.82.033826
Optical parametric amplification in gas-filled hollow core capillary for the generation of tunable pulses in the infrared
2020
International audience; Ultrashort pulses in the near-infrared (NIR) to mid-infrared (MIR) are widely used for laser matter interaction experiments, e.g. the relaxation process of carrier semiconductors and chemical dynamics at the femtosecond and attosecond time scale [1,2]. Many different approaches based on nonlinear processes or laser devices can be found to generate pulses in theses spectral ranges. Recently, four wave mixing (FWM) based parametric amplification in gas-filled hollow core capillary (HCC) has been used to create a tunable source of ultrashort pulses. For example, pulses can be generated in the visible with an energy at the 10 µJ level [4] and in the near infrared at ~1.4…
Harmonic Generation and Nonlinear Propagation: When Secondary Radiations Have Primary Consequences
2014
In this Letter, it is experimentally and theoretically shown that weak odd harmonics generated during the propagation of an infrared ultrashort ultraintense pulse unexpectedly modify the nonlinear properties of the medium and lead to a strong modification of the propagation dynamics. This result is in contrast with all current state-of-the-art propagation model predictions, in which secondary radiations, such as third harmonic, are expected to have a negligible action upon the fundamental pulse propagation. By analyzing full three-dimensional ab initio quantum calculations describing the microscopic atomic optical response, we have identified a fundamental mechanism resulting from interfere…
General approach to spatiotemporal modulational instability processes
2011
International audience; In this article, we derive the general exact solution of the modulation instability gain. The solution described here is valid for 1-D, 2-D, and 3-D cases considering any temporal response function of the medium and with possible higher order Kerr nonlinearities. In particular, we show that the gain induced by modulation instability is initial condition dependent, while the usual calculations do not lead to such a dependence. Applications for current and high-interest nonlinear propagation problems, such as 1-D optical fiber propagation with delayed Raman response and 2-D filamentation in gases, are investigated in detail. More specifically, we demonstrate that the 2-D …
Higher-order Kerr effects improve quantitative modelling of harmonics generation and laser filamentation
2013
The consideration of the higher-order Kerr effect (HOKE) drastically improves the quantitative agreement between measured and simulated harmonic yield as well as intensity and electron density in laser filaments generated by pulses below a few hundreds of fs. In longer pulses, the plasma defocusing plays a much more important role.
Four-wave mixing process induced by a self-phase modulated pulse in a hollow core capillary
2021
International audience; <span class="markedContent" id="page11R_mcid8"><span style="left: 247.583px; top: 366.24px; font-size: 16.6667px; font-family: sans-serif;" role="presentation" dir="ltr"></span><span style="left: 253px; top: 366.24px; font-size: 16.6667px; font-family: sans-serif; transform: scaleX(0.941702);" role="presentation" dir="ltr">In this work, we investigate the modal </span><span style="left: 518.183px; top: 366.24px; font-size: 16.6667px; font-family: sans-serif;" role="presentation" dir="ltr"> </span><span style="left: 519.8px; top: 366.24px; font-size: 16.6667px; font-family: sans-serif; transform: scaleX(0.958087);" role="presentation" dir="ltr">four wa…
Filamentation-induced spectral broadening and pulse shortening of infrared pulses in Tellurite glass
2016
Abstract Filamentation of infrared femtosecond pulses in Tellurite glass is reported, leading to the generation of a supercontinuum generation spanning from the visible up to 4 μm. The angular distribution of the supercontinuum shows clear evidence of conical waves generation, in particular, in the visible region. Moreover, taking advantage of the spatio-temporal self-focusing effect occurring in the Tellurite glass, a twofold pulse shortening is demonstrated. Tellurite glass appears as a very convenient, versatile and promising medium for femtosecond nonlinear optics in the infrared region.
Higher-order Kerr terms allow ionization-free filamentation in gases.
2010
We show that higher-order nonlinear indices ($n_4$, $n_6$, $n_8$, $n_{10}$) 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.
Towards CEP stable, single-cycle pulse compression with bulk material
2010
We demonstrate both experimentally and numerically that self-steepening during propagation in a hollow-fiber followed by linear propagation through glass in the anomalous dispersion enables pulse compression down to 1.6 cycles at 1.8 µm wavelength.
High-field quantum calculation reveals time-dependent negative Kerr contribution
2013
The exact quantum time-dependent optical response of hydrogen under strong field near infrared excitation is investigated and compared to the perturbative model widely used for describing the effective atomic polarization induced by intense laser fields. By solving the full 3D time-dependent Schr\"{o}dinger equation, we exhibit a supplementary, quasi-instantaneous defocusing contribution missing in the weak-field model of polarization. We show that this effect is far from being negligible in particular when closures of ionization channels occur and stems from the interaction of electrons with their parent ions. It provides an interpretation to higher-order Kerr effect recently observed in v…
Visualizing coherent molecular rotation in a gaseous medium
2021
Inducing and controlling the ultrafast molecular rotational dynamics using shaped laser fields is essential in numerous applications. Several approaches exist that allow following the coherent molecular motion in real-time, including Coulomb explosion-based techniques and recovering molecular orientation from the angular distribution of high harmonics. We theoretically consider a non-intrusive optical scheme for visualizing the rotational dynamics in an anisotropic molecular gas. The proposed method allows determining the instantaneous orientation of the principal optical axes of the gas. The method is based on probing the sample using ultra-short circularly polarized laser pulses and recor…
Optical Imaging of Coherent Molecular Rotors
2020
International audience; Short laser pulses are widely used for controlling molecular rotational degrees of freedom and inducing molecular alignment, orientation, unidirectional rotation and other types of coherent rotational motion. To follow the ultra-fast rotational dynamics in real time, several techniques for producing molecular movies have been proposed based on the Coulomb explosion of rotating molecules, or recovering molecular orientation from the angular distribution of high-harmonics. The present work offers and demonstrates a novel non-destructive optical method for direct visualization and recording of movies of coherent rotational dynamics in a molecular gas. The technique is b…
Optical parametric amplification in gas-filled hollow-core capillary for the generation of tunable pulses in the infrared
2020
International audience; Ultrashort pulses in the near-infrared (NIR) to mid-infrared (MIR) are widely used for laser matter interaction experiments, e.g. the relaxation process of carrier semiconductors and chemical dynamics at the femtosecond and attosecond time scale [1, 2]. Many different approaches based on nonlinear processes or laser devices can be found to generate pulses in theses spectral ranges. Recently, four wave mixing (FWM) based parametric amplification in gas-filled hollow core capillary (HCC) has been used to create a tunable source of ultrashort pulses. For example, pulses can be generated in the visible with an energy at the 10 µJ level [4] and in the near infrared at ~1.…
Negative and positive 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
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.
DEVICE AND METHOD FOR CHARACTERISING A FEMTOSECOND LASER PULSE
2016
The invention relates to a device for characterising a laser pulse (Pu), comprising at least: - a Fresnel biprism (BPF) that separates an incident laser beam; a detector (CAM) comprising at least one linear semiconductor detector disposed in an overlap zone in which the separated beams interfere and generate a trace by absorption of two photons of at least two beams separated by the Fresnel biprism, said generated trace comprising information characterising the laser pulse (Pu); and a computer (K) that processes a signal from the detector (CAM), produced by the generation of the trace, in order to deduce therefrom a laser pulse duration.
CHARACTERISATION OF A RADIATION PULSE BY TIME-RESOLVED OPTICAL WINDOWING
2022
The invention relates to a system (10) for characterising a pulse (I) of electromagnetic radiation by time-resolved optical windowing, which comprises an device (1) for forming an interference which is suitable for superimposing four parts of the pulse. The system also comprises a matrix image sensor (3) which selectively captures an interference pattern formed by the pulse from two-photon absorptions. Said system allows the pulse shape to be obtained completely and accurately, and is particularly suitable for characterising ultrashort pulses. In various embodiments, the two-photon absorption can be produced in the matrix image sensor, or replaced by optical frequency doubling which is prod…