showing 33 related works from this author
Femtosecond non linear pulse shaping with a pair of co-propagating solitons
2010
Manipulation expérimentale de la cohérence temporelle d'ondes partiellement cohérentes
2019
National audience; Nous décrivons deux expériences nous permettant de manipuler les propriétés de cohérence d'ondes partiellement cohérentes. Les montages expérimentaux développés reposent sur la manipulation de la phase spectrale du champ initial, assistée éventuellement d'une modulation sinusoïdale préalable de sa phase temporelle. Les signaux d'autocorrélation en intensité mesurés soulignent le changement significatif des caractéristiques temporelles des signaux incohérents obtenus.
Two-wave interferences space-time duality: Young slits, Fresnel biprism and Billet bilens
2017
International audience; Taking advantage of the analogy that can be drawn between the spatial and temporal propagations, we explore two-wave temporal interference in textbook cases such as Young's double slits, Fresnel's biprism and Billet's bilens. We illustrate our approach by numerical simulations for short pulses propagating in dispersive optical fibers with parameters typical of those found in modern optical telecommunications.
Linear and nonlinear fiber propagation of partially coherent fields exhibiting temporal correlations
2019
International audience; Using ultrafast photonic first-order differentiator applied on a partially coherent field, we report the generation of two correlated temporal waveforms and study their correlation properties upon linear and nonlinear propagation along the two orthogonal polarization axis of a dispersive optical fiber. Temporal correlations are maintained in linear propagation whereas Kerr nonlinearity generates anti-correlated temporal intensity patterns for both partially and uncorrelated fields. Experiments are in close agreement with the theoretical analysis.
All-fiber transform-limited spectral compression by self-phase modulation of amplitude shaped pulses
2012
International audience; We demonstrate efficient spectral compression of picosecond pulses in an all-fiber configuration at telecommunication wavelengths. Thanks to parabolic pulse shaping, a spectral compression by a factor 12 is achieved with an enhanced Strehl ratio.
Transverse chemical interface detection with coherent anti-Stokes Raman scattering microscopy
2011
International audience; Transverse "chemical" interfaces are revealed with a conventional two beam narrowband coherent anti-Stokes Raman scattering microscopy setup in a collinear configuration. The exciting "pump" and "Stokes" beams are focused on the sample in two opposite directions. The subtraction of the two generated anti-Stokes signals gives rise to a signal that is directly proportional to the pure Raman spectrum of the resonant medium. This property is used to highlight an interface between glass and N,N-dimethylformamide (DMF) and recover the pure Raman spectrum of DMF around its 1408 cm−1 vibrational band.
Background-free nonlinear Raman microscopy and spectroscopy at interfaces
2010
Gaussian focused beams exhibit specific properties that drive the emitted fields in nonlinear optical microscopy. We discuss here how the basic field and object symmetry properties can be favorably used to obtain background-free images and spectra in third-order nonlinear optical processes. We concentrate here on coherent anti-Stokes Raman scattering (CARS), the non-linear analogue of Raman scattering. In CARS microscopy, the vibrational related (“resonant”) signal is often overwhelmed by an electronic related (“nonresonant”) background. Various strategies have been implemented to circumvent the undesirable effects of this nonresonant background: picosecond pulse excitation, time resolved, …
The Gouy Phase Shift
2013
Réseau temporel dispersif dans une fibre optique
2015
National audience; Nous exploitons l’analogie entre les domaines temporels et spectraux pour démontrer la génération de l’équivalent temporel d’un réseau de diffraction. En combinant une modulation de phase périodique et une propagation dispersive, nous observons en effet l’émergence de répliques temporelles de l’impulsion initiale correspondant aux ordres +1 et -1 d’un réseau de diffraction traditionnel.
Méthode pour la détection d'un signal optique non linéaire résonant et dispositif pour la mise en œuvre de ladite méthode (II)
2010
L'invention concerne une méthode et un dispositif pour détecter un signal optique non linéaire résonant induit dans un échantillon, l'échantillon comprenant un milieu résonant et un milieu non résonant formant une interface, le dispositif comprenant : - une source d'émission d'au moins un premier faisceau lumineux d'excitation du milieu résonant, dit faisceau pompe, à une première pulsation omega_p donnée, ledit faisceau pompe étant incident sur l'échantillon selon un axe optique, et interceptant l'échantillon à une position donnée d'une interface transverse entre le milieu résonant et non résonant, - un premier module optique de détection du signal optique non linéaire résultant de l'inter…
Obtention d'impulsions en limite de Fourier par compression spectrale réalisée dans une fibre optique
2012
National audience; Nous démontrons la compression spectrale d'impulsions picosecondes dans un montage totalement fibré aux longueurs d'onde des télécommunications optiques. Grâce à un façonnage préalable du profil d'intensité en une parabole, un facteur de compression dépassant 10 est démontré avec un facteur de Strehl significativement augmenté par rapport à une impulsion de forme sécante hyperbolique.
Experimental observation of temporal dispersion gratings in fiber optics
2017
We experimentally demonstrate a temporal analog to the diffraction optical grating in the Fraunhofer formalism. Using amplitude and phase temporal periodic modulations, we show that the accumulation of dispersion in fiber optics induces the development of temporally well-separated sidebands similar to the spatial orders of diffraction that are commonly observed in an optical grating operating in the far field.
Enhanced Second Harmonic Generation from individual metallic nano-apertures
2010
International audience
Broadband multiplex CARS micro-spectroscopy in the picosecond regime
2010
International audience
Microscopie non-linéaire vibrationnelle CARS affranchie de bruit non-résonant aux interfaces
2010
L'effet CARS (acronyme anglais de “coherent anti-Stokes Raman scattering”) est un analogue non-linéaire de l'effet Raman. A ce titre, il donne une information vibrationnelle sur l'échantillon étudié. Utilisé en microscopie, c'est une technique résolue chimiquement et qui permet de s'affranchir de marquage fluorescent. CARS est un processus de mélange à quatre ondes dans lequel deux faisceaux laser décalés en fréquence optique dénotés « pompe » et « Stokes » interagissent avec l'échantillon d'étude pour générer un signal dénoté « anti-Stokes » et décalé vers le bleu. Le signal anti-Stokes est la somme cohérente de deux composantes : une composante vibrationnelle, dite « résonante », générée …
Spectral analog of the Gouy phase shift
2013
We demonstrate the existence of the spectral phase shift a pulse experiences when it is subjected to spectral focusing. This $\frac{\ensuremath{\pi}}{2}$ phase shift is the spectral analog of the Gouy phase shift a 2D beam experiences when it crosses its focal plane. This spectral Gouy phase shift is measured using spectral interference between a reference pulse and a negatively chirped parabolic pulse experiencing spectral focusing in a nonlinear photonic crystal fiber. To avoid inherent phase instability in the measurement, both reference and parabolic pulses are generated with a $4\mathrm{\text{\ensuremath{-}}}f$ pulse shaper and copropagate in the same fiber. We measure a spectral phase…
Experimental observation of the spectral Gouy phase shift
2013
We experimentally observe and measure the spectral phase shift of a pulse subjected to spectral focusing. We find a phase shift of π/2, reaffirming the Gouy phase shift as a general consequence of wave confinement whether in space/momentum or frequency/time coordinates.
Nonlinear pulse shaping in normally dispersive fibers : experimental examples
2014
International audience; While the combination of Kerr nonlinearity with dispersion in optical fibers can seriously impair high speed optical transmissions, it also provides an attractive solution to generate new temporal and spectral waveforms. We explain in this talk how to take advantage of the progressive temporal and spectral reshapings that occur upon propagation in a normally dispersive fiber. We base our discussion on several experimental results obtained at telecommunication wavelengths.
Transform-limited spectral compression by self-phase modulation of amplitude-shaped pulses with negative chirp
2011
International audience; Spectral compression by self-phase modulation of amplitude- and phase-shaped pulses is demonstrated as superior compared to pulses that have only been phase shaped. We synthesize linearly negatively chirped parabolic pulses, which we send through a nonlinear photonic crystal fiber, in which self-phase modulation compresses the spectrum of the pulses to within 20% of the Fourier transform limit.
Fibre optique microstructurée double gaine et coeur creux : Vers un endoscope CARS
2010
Nonlinear Pulse Shaping Using photonic Crystal fibers
2010
All-fiber spectral compression of picosecond pulses at telecommunication wavelength enhanced by amplitude shaping
2012
International audience; We demonstrate efficient spectral compression of picosecond pulses in an all-fiber configuration at telecommunication wavelengths. A spectral compression by a factor 12 is achieved. Performing temporal shaping with a parabolic pulse significantly improves the spectral compression with much lower substructures and an enhanced Strehl ratio.
Source optique fibrée pour la microscopie CARS
2012
Nonlinear fiber propagation of partially coherent fields exhibiting temporal correlations
2020
Using photonic first-order differentiator applied on a partially coherent field, we generate two correlated temporal waveforms and experimentally study their correlation properties upon nonlinear propagation along the two orthogonal polarization axis of an optical fiber.
Coherent Anti-Stokes Raman Scattering (CARS) in a microcavity
2009
Experimental control over soliton interaction in optical fiber by pre-shaped input field
2011
Interactions between femtosecond solitons in a nonlinear photonic-crystal fiber are of fundamental interest. But many practical applications would abound if solitons could be arbitrarily superposed into multiples in the fiber. Here, we numerically and experimentally demonstrate a first step towards this aim, the creation of a soliton pair with arbitrary relative phase, delay, and frequency throughout almost the entire output parameter space with the aid of a pre-shaped fiber input field.
Polarized multiplex coherent anti-Stokes Raman scattering using a picosecond laser and a fiber supercontinuum
2011
International audience; We perform multiplex coherent anti-Stokes Raman scattering (CARS) micro-spectroscopy with a picosecond pulsed laser and a broadband supercontinuum (SC) generated in photonic crystal fiber. CARS signal stability is achieved using an active fiber coupler that avoids thermal and mechanical drifts. We obtain multiplex CARS spectra for test liquids in the 600–2000 cm−1 spectral range. In addition we investigate the polarization dependence of the CARS spectra when rotating the pump beam linear polarization state relative to the linearly polarized broad stokes SC. From these polarization measurements we deduce the Raman depolarization ratio, the resonant versus nonresonant …
Impact of initial pulse shape on the nonlinear spectral compression in optical fibre
2018
International audience; We theoretically study the effects of the temporal intensity profile of the initial pulse on the nonlinear spectral compression process arising from nonlinear propagation in an optical fibre. Various linearly chirped input pulse profiles are considered, and their dynamics is explained with the aid of time-frequency representations. While initially parabolic-shaped pulses show enhanced spectral compression compared to Gaussian pulses, no significant spectral narrowing occurs when initially super-Gaussian pulses are used. Triangular pulses lead to a spectral interference phenomenon similar to the Fresnel bi-prism experiment.
Optimisation de la densité spectrale d'énergie obtenue par auto-décalage fréquentiel Raman dans une fibre microstructurée
2010
National audience
Polarization-resolved coherent Raman microscopy
2010
International audience
Nonlinear pulse shaping by coherent addition of multiple redshifted solitons
2011
International audience; The injection of a phase- and amplitude-shaped pulse into a photonic-crystal fiber provides additional degrees of freedom that can significantly influence the nature of nonlinear propagation and nonlinear and dispersive interactions. This strong sensitivity of nonlinear effects-particularly the Raman soliton self-frequency shift-greatly extends the parameter space available to generate tailored output fields for applications such as microscopic imaging. By numerical simulations, we identify the relevant interpulse interactions, and we experimentally demonstrate the additional capabilities of this nonlinear pulse-shaping method.
La tache d’Arago temporelle en optique fibrée non-linéaire
2021
National audience
Propagation non-linéaire de champs partiellement incohérents mais avec une cohérence mutuelle contrôlée
2021
National audience