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Séminaires - Colloquiums - Institut des Sciences de la Lumière

 

 

 

Watching atoms and electrons in action with HHG and short wavelength free electron laser sources

Kiyoshi UEDA

kiyoshi.ueda@tohoku.ac.jp 

Tohoku University, Sendai, Japan

The present talk will illustrate the current status of short-wavelength free-electron laser (FEL) experiments, focusing on
characteristic properties of different facilities and compare them with laboratory-based HHG source experiments. The
advent of hard x-ray FELs, such as SACLA in Japan, opened a route to extract the structure of a single nanoparticle [1] and its change upon the intense laser irradiation, which transforms the nanoparticle into a nanoplasma [2]. The first high repetition rate soft x-ray FEL, the European XFEL, combined with a Reaction Microscope/COLTRIMS, made the long-standing dream to watch atoms in action - initiated by photoexcitation of a molecule - a tangible reality, using the so-called core-level photoelectron diffraction technique for fixed-in-space molecules [3]. Generation of two-color attosecond pulse pairs at the LCLS in the USA finally opened the door to watching charge migration in a molecule, before the nuclear dynamics sets in, with an attosecond transient absorption technique based on the detection of resonant Auger electrons [4]. Generating phase-coherent multi-color pulses at FERMI, on the other hand, provided a novel approach to coherently control the electronic wave-packets [5] and to read out the photoionization phase [6]. One can also directly access the energy dependent photoionization phases, or the photoionization time delays, by using the RABBITT technique with a laboratory-based HHG source, or attosecond pulse trains, which could also be used for studying the attosecond trapping of photoelectrons by the molecular shape resonances [7]. These works were carried out by a wide range of international
collaborations. I acknowledge all the collaborators in the authors list of [1-7] for fruitful collaborations.
[1] A. Niozu et al., IUCrJ 7, 276 (2020); A. Niozu et al., PNAS 118, e2111747118 (2021).
[2] T. Nishiyama et al., PRL 123, 123201 (2019); A. Niozu et al., PRX 11, 031046 (2021).
[3] G. Kastire et al., PRX 10, 021052 (2020).
[4] T. Barillot et al., PRX 11, 031048 (2021).
[5] K. Prince et al., Nature Photonics 10, 176 (2016); D. Iablonskyi et al., PRL 119, 073203 (2017).
[6] M. Di Fraia et al., PRL 123, 213904 (2019); D. You et al., PRX 10, 031070 (2020).
[7] X. Dong et al., PRX 12, 011002 (2022).

 

28 Juin 2022 à 11h au LIDYL, CEA Paris-Saclay, L'Orme des Merisiers, Bât 701, salle 17C, 91191 Gif-sur-Yvette

To attend the meeting via zoom:
https://cnrs.zoom.us/j/93622375451?pwd=b0lUR2xWRUpHU1htZVVBV3dONW1vdz09

Pollution/Climat : Que peut-on voir depuis l'espace avec le sondeur infrarouge IASI ?

Cathy Clerbaux

Cathy.Clerbaux@latmos.ipsl.fr

LATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, France

Le sondeur infrarouge IASI, construit par le CNES, vole à bord des 3 satellites Metop depuis 2006. Après plus de 15 années passées en orbite, le bilan de la mission IASI, en termes de retour scientifique, technologique et d’impact sociétal, est impressionnant. Les services météorologiques ont établi qu’il s’agit du meilleur sondeur météorologique jamais développé, apportant une contribution essentielle à la qualité des prévisions météorologiques. IASI est aussi le seul instrument qui mesure simultanément deux fois par jour en tout point du globe une vingtaine de composés atmosphériques, en temps réel.
L’exposé donnera des exemples des avancées récentes pour le suivi de la composition atmosphérique: les observations permettent de surveiller les pics de pollution au-dessus de l’ile de France, les panaches de gaz qui s’échappent de Chine, les grands feux qui font rage en été, les émissions d’ammoniac associées à l’agriculture intensive (première cartographie effectuée depuis l’espace), les épisodes météorologiques exceptionnels, ou encore la formation du trou dans la couche d’ozone. IASI a aussi joué un rôle important dans la fourniture de données permettant d’émettre des alertes rapides lors d’éruptions volcaniques, afin d’éviter le survol des zones contaminées en cendre par les avions ou de mettre en place des alertes d’évacuation des populations locales.

  • 19 Mai 2022 à 11h à l'AUDITORIUM de l'Institut d’Optique, 2 Av. Augustin Fresnel, 91127 Palaiseau

Polaritons in semiconductor lattices: emulating condensed matter physics

Jacqueline Bloch

jacqueline.bloch@universite-paris-saclay.fr

Center for Nanoscience and Nanotechnology, C2N / Université Paris Saclay / CNRS, Palaiseau, France

Photonic resonators, coupled within a lattice, have appeared in the recent years as a powerful synthetic platform to imprint on light some of the fascinating physical properties that can emerge in condensed matter, or even to go beyond what exists in nature. For instance, light can become superfluid, present spin orbit coupling, spin Hall effect or propagate along topologically protected edge states. New physical properties may emerge when drive and dissipation come into play. Such realizations are not only interesting from a fundamental point of view, but also inspire innovative photonic devices.
After a general introduction to polariton physics and polariton lattices [1], I will present some recent experiments we have performed at C2N. Using lattices of semiconductor microcavities, we explore single and many body physics of photons in 1D or 2D lattices and the emergence of novel physics related to the openness of the system [2]. Topological physics can be investigated when non-linearities come into play[3]. Interestingly, our photonic platform also enables exploring universal scaling related to the Kardar–Parisi–Zhang universality class [4].

References :
[1] Ciuti and I. Carusotto, Quantum fluids of light, Rev. Mod. Phys. 85, 299 (2013).
[2] A. Amo and J. Bloch, Exciton-polaritons in lattices: A non-linear photonic simulator, Comptes Rendus de l’Académie des Sciences 8, 805 (2016) (Elsevier).
[3] N. Pernet et al., Topological gap solitons in a 1D non-Hermitian lattice, arXiv:2101.01038 (to appear 2022).
[4] Q. Fontaine et al., Observation of KPZ universal scaling in a one-dimensional polariton condensate, arXiv:2112.09550 (2021).

  • 22 Avril 2022 à 11h à l'AUDITORIUM de l'Institut d’Optique, 2 Av. Augustin Fresnel, 91127 Palaiseau

 

Rise of the Machines: Making better photons by getting rid of experimentalists

Andrew White

Jihun Cha , Sebastian Malewicz , Fatemeh Mohit , Marcelo Alemida , Till Weinhold , and Andrew White

Centre for Engineered Quantum Systems , School of Mathematics and Physics , University of Queensland, Brisbane 4072, Australia

There is now an enormous opportunity to interconnect quantum components together into complex short and long range networks of sensing communication, and computational elements Photons are a natural choice for networking quantum technologies as their quantum nature survives at room temperature and long distance propagation is possible, either via optical fibre or through free space.

Here we explore using machine learning ( to optimise production, coupling routing and circuitry for single photons Our single photon source platform is resonant excitation of individual quantum dots coupled to a micropillar cavity Multiphoton suppression in the quantum dot emission as well as single photon indistinguishability and brightness are directly influenced by the spatiotemporal characteristics of the optical excitation pulses We use ML techniques to tailor the excitation laser pulse properties in real time, significantly reducing the search time for optimal parameters We also employ ML to control a deformable mirror correcting for aberration on the single photon wavefront field to maximise the coupling between the source output and a single mode fibre This combination provides a toolbox for enhancing the performance of any solid state single photon source.

Photonic integrated circuits ( will be essential for scalaby realising photonic quantum technologies Actively coupling photons into PICS requires high fidelity integrated switches Current best practice manual optimisation of electronic signals for each individual switch on a chip is slow and unscalable We use ML simulated annealing to optimise driving parameters for up to 4 switches on a single chip, achieving a significant speed up in tuning while retaining optimal performance PICS often interface light in and out of the chip using edge coupling which severely limits chip geometry as well as adding complication to fabrication Using ML inverse design we are developing efficient out of plane couplers and small footprint waveguide crossings that are easier to manufacture and have higher circuit density This new architecture lowers entry costs for photonic integrated circuitry development.

  • 25 Mars 2022 à 14h à l'amphithéâtre C2N - Centre de nanosciences et de naotechnologies, Palaiseau.

L'imagerie EUV pour explorer le Soleil : premiers résultats de la mission Spatiale Solar Orbiter

Frédéric Auchère
Astronome
Institut d'Astrophysique Spatiale

frederic.auchere@universite-paris-saclay.fr
 

L'imagerie et la spectroscopie UV/EUV sont des outils indispensables pour l'astrophysique. Les couronnes solaire et stellaires sont des plasmas portées à des températures de l'ordre du million de degrés qui émettent de nombreuses raies d’émission dans cette gamme du spectre. La mission Solar Orbiter, lancée avec succès en février 2020, embarque à son bord plusieurs instruments UV/EUV, réalisés avec une forte contribution de laboratoires français. Les caractéristiques uniques de l'orbite de la sonde l'amèneront à 0.29 unités astronomiques et 35° d’inclinaison par rapport au plan de l'écliptique, permettant des vues inédites de notre étoile. Nous verrons les caractéristiques principales des instruments utilisés ainsi que les premiers résultats déjà obtenus, dont des images parmi les plus détaillées jamais réalisées de la couronne du Soleil.

  • 15/03/2022 à 11h à l’Auditorium de l’Institut d’Optique (2 Av. Augustin Fresnel, 91120 Palaiseau)

Lien zoom pour assister au séminaire

 

Bright and Fast: Lasers to Capture the Dance Between Electrons and Nuclei in Molecular Systems

Nora Berrah

Chaire Blaise Pascal de la région d’Ile de France*

University of Connecticut, Physics department, Storrs, CT, USA
Groupe AttoPhysique, LIDYL, Université Paris-Saclay, CEA, CNRS, France


Photoionization of atoms, molecules, and small complexes creates a fundamental testing ground to understand better quantum mechanical phenomena arising from the interaction of photon with matter. With the ultrafast (~10-15 s) light sources, such as lab-based tabletop lasers and facility-based free electron lasers (FELs), one can investigate molecular processes in the time domain, thus mapping out their evolution. In that regard, it is possible to “make a molecular movie” of ultrafast reaction dynamics. In the seminar, we will present some of our work using photons in the XUV and X-ray regime from the Linac Coherent Light Source (LCLS) FEL at SLAC National Laboratory as well as the FLASH FEL in Hamburg, Germany.

  • 22/02/2022 à 11h à l’Auditorium de l’Institut d’Optique (2 Av. Augustin Fresnel, 91120 Palaiseau)

* Action financée par la région d'lle de France 

Prochains colloquiums

  • Frédéric Auchère, Institut d'Astrophysique Spatiale, 15 mars (11h), « L'imagerie EUV pour explorer le Soleil: premiers résultats de la mission Spatiale Solar Orbiter »
  • Jacqueline Bloch, Centre de Nanosciences et de Nanotechnologies (C2N), 22 avril (11h), « Polaritons in semiconductor lattices: emulating condensed matter physics »