Laser-Induced Electron Diffraction in Chiral Molecules

Strong laser pulses enable probing molecules with their own electrons. The oscillating electric field tears electrons off a molecule, accelerates them, and drives them back toward their parent ion within a few femtoseconds. The electrons are then diffracted by the molecular potential, encoding its structure and dynamics with angstrom and attosecond resolutions. Using elliptically polarized laser pulses, we show that laser-induced electron diffraction is sensitive to the chirality of the target. The field selectively ionizes molecules of a given orientation and drives the electrons along different sets of trajectories, leading them to recollide from different directions. Depending on the handedness of the molecule, the electrons are preferentially diffracted forward or backward along the light propagation axis. This asymmetry, reaching several percent, can be reversed for electrons recolliding from two ends of the molecule. The chiral sensitivity of laser-induced electron diffraction opens a new path to resolve ultrafast chiral dynamics

Shaped liquid drops generate MeV temperature electron beams with millijoule class laser

MeV temperature electrons are typically generated at laser intensities of 1018 W cm−2. Their generation at non-relativistic intensities (~1016 W cm−2) with high repetition rate lasers is cardinal for the realization of compact, ultra-fast electron sources. Here we report a technique of dynamic target structuring of micro-droplets using a 1 kHz, 25 fs, millijoule class laser, that uses two collinear laser pulses; the first to create a concave surface in the liquid drop and the second, to dynamically-drive electrostatic plasma waves that accelerate electrons to MeV energies. The acceleration mechanism, identified as two plasmon decay instability, is shown to generate two beams of electrons with hot electron temperature components of 200 keV and 1 MeV, respectively, at an intensity of 4 × 1016 Wcm−2, only. The electron beams are demonstrated to be ideal for single shot high resolution (tens of μm) electron radiography

Shaped liquid drops generate MeV temperature electron beams with millijoule class laser

MeV temperature electrons are typically generated at laser intensities of 1018 W cm−2. Their generation at non-relativistic intensities (~1016 W cm−2) with high repetition rate lasers is cardinal for the realization of compact, ultra-fast electron sources. Here we report a technique of dynamic target structuring of micro-droplets using a 1 kHz, 25 fs, millijoule class laser, that uses two collinear laser pulses; the first to create a concave surface in the liquid drop and the second, to dynamically-drive electrostatic plasma waves that accelerate electrons to MeV energies. The acceleration mechanism, identified as two plasmon decay instability, is shown to generate two beams of electrons with hot electron temperature components of 200 keV and 1 MeV, respectively, at an intensity of 4 × 1016 Wcm−2, only. The electron beams are demonstrated to be ideal for single shot high resolution (tens of μm) electron radiography

Measuring and manipulating chiral light-matter interaction on the attosecond timescale

Les molécules chirales existent sous deux formes images mirroir, appelées énantiomères, qui ont les mêmes propriétés physiques et chimiques et ne peuvent être distinguées que via leur interaction avec un autre système chirale, comme de la lumière polarisée circulairement. De nombreux processus biologiques sont chiro-sensibles, et élucider les aspects dynamiques de la chiralité est d’importance primordiale pour la chimie, la biologie et la pharmacologie. L’étude des processus chiraux ultrarapides nécessite de nouvelles techniques expérimentales à l’échelle attoseconde. L’objectif de cette thèse sera de développer de nouvelles approches pour mesurer et contrôler l’interaction lumière-matière chirale en utilisant les trois pilliers de la science attoseconde: la génération d’harmoniques d’ordre élevé, la photoionisation, et l’absorption transitoire.Chiral molecules exist as two mirror forms, so-called enantiomers, which haveessentially the same physical and chemical properties and can only be distinguished via theirinteraction with a chiral system, such as circularly polarized light. Many biological processesare chiral-sensitive and unraveling the dynamical aspects of chirality is of prime importancefor chemistry, biology and pharmacology. Studying the ultrafast electron dynamics of chiralprocesses requires characterization techniques at the attosecond timescale. The thesis aimsat developing new approaches to measure and manipulate chiral lightmatter interaction usingthe three pillars of attosecond science: high-order harmonic generation, photoionization, andtransient absorption

Mesure et contrôle de l'interaction lumière-matière chirale à l'échelle attoseconde.

Chiral molecules exist as two mirror forms, so-called enantiomers, which haveessentially the same physical and chemical properties and can only be distinguished via theirinteraction with a chiral system, such as circularly polarized light. Many biological processesare chiral-sensitive and unraveling the dynamical aspects of chirality is of prime importancefor chemistry, biology and pharmacology. Studying the ultrafast electron dynamics of chiralprocesses requires characterization techniques at the attosecond timescale. The thesis aimsat developing new approaches to measure and manipulate chiral lightmatter interaction usingthe three pillars of attosecond science: high-order harmonic generation, photoionization, andtransient absorption.Les molécules chirales existent sous deux formes images mirroir, appelées énantiomères, qui ont les mêmes propriétés physiques et chimiques et ne peuvent être distinguées que via leur interaction avec un autre système chirale, comme de la lumière polarisée circulairement. De nombreux processus biologiques sont chiro-sensibles, et élucider les aspects dynamiques de la chiralité est d’importance primordiale pour la chimie, la biologie et la pharmacologie. L’étude des processus chiraux ultrarapides nécessite de nouvelles techniques expérimentales à l’échelle attoseconde. L’objectif de cette thèse sera de développer de nouvelles approches pour mesurer et contrôler l’interaction lumière-matière chirale en utilisant les trois pilliers de la science attoseconde: la génération d’harmoniques d’ordre élevé, la photoionisation, et l’absorption transitoire

Measuring and manipulating chiral light-matter interaction on the attosecond timescale

Les molécules chirales existent sous deux formes images mirroir, appelées énantiomères, qui ont les mêmes propriétés physiques et chimiques et ne peuvent être distinguées que via leur interaction avec un autre système chirale, comme de la lumière polarisée circulairement. De nombreux processus biologiques sont chiro-sensibles, et élucider les aspects dynamiques de la chiralité est d’importance primordiale pour la chimie, la biologie et la pharmacologie. L’étude des processus chiraux ultrarapides nécessite de nouvelles techniques expérimentales à l’échelle attoseconde. L’objectif de cette thèse sera de développer de nouvelles approches pour mesurer et contrôler l’interaction lumière-matière chirale en utilisant les trois pilliers de la science attoseconde: la génération d’harmoniques d’ordre élevé, la photoionisation, et l’absorption transitoire.Chiral molecules exist as two mirror forms, so-called enantiomers, which haveessentially the same physical and chemical properties and can only be distinguished via theirinteraction with a chiral system, such as circularly polarized light. Many biological processesare chiral-sensitive and unraveling the dynamical aspects of chirality is of prime importancefor chemistry, biology and pharmacology. Studying the ultrafast electron dynamics of chiralprocesses requires characterization techniques at the attosecond timescale. The thesis aimsat developing new approaches to measure and manipulate chiral lightmatter interaction usingthe three pillars of attosecond science: high-order harmonic generation, photoionization, andtransient absorption

Mesure et contrôle de l'interaction lumière-matière chirale à l'échelle attoseconde.

Chiral molecules exist as two mirror forms, so-called enantiomers, which haveessentially the same physical and chemical properties and can only be distinguished via theirinteraction with a chiral system, such as circularly polarized light. Many biological processesare chiral-sensitive and unraveling the dynamical aspects of chirality is of prime importancefor chemistry, biology and pharmacology. Studying the ultrafast electron dynamics of chiralprocesses requires characterization techniques at the attosecond timescale. The thesis aimsat developing new approaches to measure and manipulate chiral lightmatter interaction usingthe three pillars of attosecond science: high-order harmonic generation, photoionization, andtransient absorption.Les molécules chirales existent sous deux formes images mirroir, appelées énantiomères, qui ont les mêmes propriétés physiques et chimiques et ne peuvent être distinguées que via leur interaction avec un autre système chirale, comme de la lumière polarisée circulairement. De nombreux processus biologiques sont chiro-sensibles, et élucider les aspects dynamiques de la chiralité est d’importance primordiale pour la chimie, la biologie et la pharmacologie. L’étude des processus chiraux ultrarapides nécessite de nouvelles techniques expérimentales à l’échelle attoseconde. L’objectif de cette thèse sera de développer de nouvelles approches pour mesurer et contrôler l’interaction lumière-matière chirale en utilisant les trois pilliers de la science attoseconde: la génération d’harmoniques d’ordre élevé, la photoionisation, et l’absorption transitoire

Interaction of Tungsten tips with Laguerre-Gaussian beams

Interaction of femtosecond laser pulses with metallic tips have been studied extensively and they have proved to be a very good source of ultrashort electron pulses. We present our study of interaction of Laguerre-Gaussian (LG) laser modes with Tungsten tips. We report a change in the order of the interaction for LG beams and the difference in the order of interaction is attributed to ponderomotive shifts in the energy levels corresponding to the enhanced near field intensity supported by numerical simulations

Ultrafast polarization-tunable monochromatic extreme ultraviolet source at high-repetition-rate

International audienceWe report on the development of a high-order harmonic generation (HHG)-based ultrafast high-repetition-rate (250 kHz) monochromatic extreme ultraviolet (21.6 eV) source with polarization tunability, specifically designed for multi-modal dichroism in time- and angle-resolved photoemission spectroscopy. Driving HHG using an annular beam allows us to spatially separate the high-power 515 nm driving laser from the XUV beamlet while preserving the linear polarization axis angle tunability. This enables controlling the polarization state of the XUV radiation with a fixed all-reflective phase-shifter. This scheme leads to a source brightness of 5.7 × 10 12 photons s −1 at 21.6 eV (up to 4 × 10 11 photons s −1 on target) with ellipticities as high as 90%