... The Chordoma Foundation requests cell lines or animal models that can be used for research in... more ... The Chordoma Foundation requests cell lines or animal models that can be used for research into chor Immortalized Insect Cell Line for Neuronal Studies. ... Femtosecond time-resolved X-ray diffraction from laser-heated organic films. ...
By focusing an ultraintense laser onto a helium gaz jet, a collimated beam of ultrafast broadband... more By focusing an ultraintense laser onto a helium gaz jet, a collimated beam of ultrafast broadband X-ray radiation can now be generated. The X-ray radiation results from the betatron oscillations of relativistic electrons in the laser created plasma channel. Thus, just as in a synchrotron, the spectral and flux properties of the X-ray beam can be linked to the electron beam through the plasma wiggler strength. The radiation has been observed within 1-10 keV with filters and presents a divergence of as low as 20 mrad. In addition, this source possesses the unique properties to be ultrafast and perfectly synchronized with the laser system, which opens the way toward new types of pump probe experiments.
Laser-plasma technology promises a drastic reduction of the size of high-energy electron accelera... more Laser-plasma technology promises a drastic reduction of the size of high-energy electron accelerators. It could make free-electron lasers available to a broad scientific community and push further the limits of electron accelerators for high-energy physics. Furthermore, the unique femtosecond nature of the source makes it a promising tool for the study of ultrafast phenomena. However, applications are hindered by the lack of suitable lens to transport this kind of high-current electron beams mainly due to their divergence. Here we show that this issue can be solved by using a laser-plasma lens in which the field gradients are five order of magnitude larger than in conventional optics. We demonstrate a reduction of the divergence by nearly a factor of three, which should allow for an efficient coupling of the beam with a conventional beam transport line.
2007 Quantum Electronics and Laser Science Conference, 2007
We show that the reflectivity of laser-excited solid relates to phonons, driven by thermal forces... more We show that the reflectivity of laser-excited solid relates to phonons, driven by thermal forces, through the electron-phonon coupling rate. Controlled excitation of phonons is available by the optimum combination of laser and material parameters.
Ultrafast time-resolved optical spectroscopy has revealed new classes of physical, chemical and b... more Ultrafast time-resolved optical spectroscopy has revealed new classes of physical, chemical and biological reactions, in which directed, deterministic motions of atoms have a key role. This contrasts with the random, diffusive motion of atoms across activation barriers that typically determines kinetic rates on slower timescales. An example of these new processes is the ultrafast melting of semiconductors, which is believed to arise from a strong modification of the inter-atomic forces owing to laser-induced promotion of a large fraction (10% or more) of the valence electrons to the conduction band. The atoms immediately begin to move and rapidly gain sufficient kinetic energy to induce melting--much faster than the several picoseconds required to convert the electronic energy into thermal motions. Here we present measurements of the characteristic melting time of InSb with a recently developed technique of ultrafast time-resolved X-ray diffraction that, in contrast to optical spect...
Applications of X Rays Generated from Lasers and Other Bright Sources II, 2001
ABSTRACT We have characterized the ultrafast solid-liquid transition of InSb and CdTe semiconduct... more ABSTRACT We have characterized the ultrafast solid-liquid transition of InSb and CdTe semiconductors by time resolved x-ray diffraction in the femtosecond timescale. Visible spectroscopic data were obtained together with x-ray measurements to characterize the dense electron-ho9le plasma at the origin of the phase transition following the IR excitation.
2008 Conference on Lasers and Electro-Optics, 2008
We present the first detailed spectral measurement of 1-3 keV Betatron X-ray radiation with two h... more We present the first detailed spectral measurement of 1-3 keV Betatron X-ray radiation with two high resolution crystal spectrometers. Electron trajectories in the laser produced plasma can be determined with this measurement.
The energy distribution and yield of electrons and hard x-ray photons were investigated by irradi... more The energy distribution and yield of electrons and hard x-ray photons were investigated by irradiating tungsten and tantalum targets with ~ 30 fs pulses in the intensity range 1018 --- 1019 W cm-2 by using the Laboratoire d'Optique Appliquee (LOA) as well as the Max Born Institut (MBI) multiterawatt Ti:sapphire lasers. For the measurement of the hard x-ray emission in
We demonstrate that betatron x-ray radiation accurately provides direct imaging of electrons traj... more We demonstrate that betatron x-ray radiation accurately provides direct imaging of electrons trajectories accelerated in laser wakefields. Experimental far field x-ray beam profiles reveal that electrons can follow similar transverse trajectories with typical excursions of 1.5 microm+/-0.5 microm in the plane of laser polarization and 0.7 microm+/-0.2 microm in the plane perpendicular.
... The Chordoma Foundation requests cell lines or animal models that can be used for research in... more ... The Chordoma Foundation requests cell lines or animal models that can be used for research into chor Immortalized Insect Cell Line for Neuronal Studies. ... Femtosecond time-resolved X-ray diffraction from laser-heated organic films. ...
By focusing an ultraintense laser onto a helium gaz jet, a collimated beam of ultrafast broadband... more By focusing an ultraintense laser onto a helium gaz jet, a collimated beam of ultrafast broadband X-ray radiation can now be generated. The X-ray radiation results from the betatron oscillations of relativistic electrons in the laser created plasma channel. Thus, just as in a synchrotron, the spectral and flux properties of the X-ray beam can be linked to the electron beam through the plasma wiggler strength. The radiation has been observed within 1-10 keV with filters and presents a divergence of as low as 20 mrad. In addition, this source possesses the unique properties to be ultrafast and perfectly synchronized with the laser system, which opens the way toward new types of pump probe experiments.
Laser-plasma technology promises a drastic reduction of the size of high-energy electron accelera... more Laser-plasma technology promises a drastic reduction of the size of high-energy electron accelerators. It could make free-electron lasers available to a broad scientific community and push further the limits of electron accelerators for high-energy physics. Furthermore, the unique femtosecond nature of the source makes it a promising tool for the study of ultrafast phenomena. However, applications are hindered by the lack of suitable lens to transport this kind of high-current electron beams mainly due to their divergence. Here we show that this issue can be solved by using a laser-plasma lens in which the field gradients are five order of magnitude larger than in conventional optics. We demonstrate a reduction of the divergence by nearly a factor of three, which should allow for an efficient coupling of the beam with a conventional beam transport line.
2007 Quantum Electronics and Laser Science Conference, 2007
We show that the reflectivity of laser-excited solid relates to phonons, driven by thermal forces... more We show that the reflectivity of laser-excited solid relates to phonons, driven by thermal forces, through the electron-phonon coupling rate. Controlled excitation of phonons is available by the optimum combination of laser and material parameters.
Ultrafast time-resolved optical spectroscopy has revealed new classes of physical, chemical and b... more Ultrafast time-resolved optical spectroscopy has revealed new classes of physical, chemical and biological reactions, in which directed, deterministic motions of atoms have a key role. This contrasts with the random, diffusive motion of atoms across activation barriers that typically determines kinetic rates on slower timescales. An example of these new processes is the ultrafast melting of semiconductors, which is believed to arise from a strong modification of the inter-atomic forces owing to laser-induced promotion of a large fraction (10% or more) of the valence electrons to the conduction band. The atoms immediately begin to move and rapidly gain sufficient kinetic energy to induce melting--much faster than the several picoseconds required to convert the electronic energy into thermal motions. Here we present measurements of the characteristic melting time of InSb with a recently developed technique of ultrafast time-resolved X-ray diffraction that, in contrast to optical spect...
Applications of X Rays Generated from Lasers and Other Bright Sources II, 2001
ABSTRACT We have characterized the ultrafast solid-liquid transition of InSb and CdTe semiconduct... more ABSTRACT We have characterized the ultrafast solid-liquid transition of InSb and CdTe semiconductors by time resolved x-ray diffraction in the femtosecond timescale. Visible spectroscopic data were obtained together with x-ray measurements to characterize the dense electron-ho9le plasma at the origin of the phase transition following the IR excitation.
2008 Conference on Lasers and Electro-Optics, 2008
We present the first detailed spectral measurement of 1-3 keV Betatron X-ray radiation with two h... more We present the first detailed spectral measurement of 1-3 keV Betatron X-ray radiation with two high resolution crystal spectrometers. Electron trajectories in the laser produced plasma can be determined with this measurement.
The energy distribution and yield of electrons and hard x-ray photons were investigated by irradi... more The energy distribution and yield of electrons and hard x-ray photons were investigated by irradiating tungsten and tantalum targets with ~ 30 fs pulses in the intensity range 1018 --- 1019 W cm-2 by using the Laboratoire d'Optique Appliquee (LOA) as well as the Max Born Institut (MBI) multiterawatt Ti:sapphire lasers. For the measurement of the hard x-ray emission in
We demonstrate that betatron x-ray radiation accurately provides direct imaging of electrons traj... more We demonstrate that betatron x-ray radiation accurately provides direct imaging of electrons trajectories accelerated in laser wakefields. Experimental far field x-ray beam profiles reveal that electrons can follow similar transverse trajectories with typical excursions of 1.5 microm+/-0.5 microm in the plane of laser polarization and 0.7 microm+/-0.2 microm in the plane perpendicular.
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Papers by A. Rousse