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PhD subjects

13 sujets IRAMIS

Dernière mise à jour : 05-06-2020


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• Radiation-matter interactions

 

Coulomb phase in Rare-Earth hyperkagome networks

SL-DRF-20-0539

Research field : Radiation-matter interactions
Location :

Laboratoire Léon Brillouin

Groupe 3 Axes

Saclay

Contact :

SYLVAIN PETIT

Starting date : 01-10-2020

Contact :

SYLVAIN PETIT
CEA - DRF/IRAMIS/LLB/G3A

01 69 08 60 39

Thesis supervisor :

SYLVAIN PETIT
CEA - DRF/IRAMIS/LLB/G3A

01 69 08 60 39

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=spetit

Laboratory link : http://www-llb.cea.fr/NFMQ/

The last decades in solid-state research have seen the rise of rich and novel physics, beyond the Néel paradigm and transcending conventional descriptions based on Landau theory. Frustrated magnetism has contributed to these developments in major ways, through new concepts like the “Coulomb phase”, a highly degenerate state of matter brought to light by the discovery of spin ice in rare-earth pyrochlore networks. In the following PhD proposal, our aim is to use hyperkagome networks of rare-earths to further explore and develop this new physics.



Towards optical Cycle Dynamics Solids

SL-DRF-20-1007

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique (ATTO)

Saclay

Contact :

Stéphane GUIZARD

Starting date : 01-09-2020

Contact :

Stéphane GUIZARD
CEA - DRF/IRAMIS/LIDyL

0169087886

Thesis supervisor :

Stéphane GUIZARD
CEA - DRF/IRAMIS/LIDyL

0169087886

Personal web page : http://iramis.cea.fr/Pisp/stephane.guizard/

Laboratory link : http://iramis.cea.fr/LIDYL/ATTO/

More : https://loa.ensta-paristech.fr/research/appli-research-group/

The fundamental TOCYDYS research program aims to probe the dynamics of solids with temporal resolution at the optical cycle scale and to cross the femtosecond resolution limit. We will initially concentrate on insulators such as silica and quartz (SiO2) or sapphire (Al2o3).

The experiments will be carried out on the facilities recently opened at LOA and LIDYL of Equipex Attolab (http://attolab.fr/), where we will have access to phase-stabilized lasers and associated ultra short VUV pulses.

The experiments will consist of exciting the samples with pulses of a few optical cycles (intensity in the range 1012 to 1015 W/cm2) and probing the dynamics by measuring change of reflectivity, in the IR and visible domains, then with attosecond pulse trains in the VUV.

We will have direct access to the physical mechanisms of the material laser interaction and to the initial stages of the electronic relaxation of the solid: multiphoton, tunnel or Zener ionization, modulation of the band gap, inelastic diffusion of the carriers, impact ionization, Auger effect, etc.

During the first part of the program, at the Laboratory of Applied Optics- LOA, the measurements will be made in the visible and near IR domains, with the objective to achieve the resolution of the optical cycle. Then, in the second part, we will construct a set-up for the reflectivity measurement in the VUV domain, capable of recording variations in the amplitude of the probe pulse, but also of the phase using spatial interferometry in the VUV domain.

The TOCYDYS research program received funding from the National Research Agency (ANR) for the period 2020-2023. So the Masters internship is funded. The experimental part will be conducted at LOA in collaboration with Davide Boschetto (https://loa.ensta-paristech.fr/research/appli-research-group/).

Influence of a nano-antenna on the intersystem crossing rate of a single molecule

SL-DRF-20-1085

Research field : Radiation-matter interactions
Location :

Service de Physique de l’Etat Condensé

Laboratoire d’Electronique et nanoPhotonique Organique

Saclay

Contact :

Simon VASSANT

Fabrice CHARRA

Starting date : 01-10-2020

Contact :

Simon VASSANT
CEA - DRF/IRAMIS

+33 169 089 597

Thesis supervisor :

Fabrice CHARRA
CEA - DRF/IRAMIS

+33/169089722

Personal web page : http://iramis.cea.fr/Pisp/simon.vassant/index.php

Laboratory link : http://iramis.cea.fr/SPEC/LEPO

As part of the ANR JCJC PlasmonISC project, we are proposing a mainly experimental thesis subject in nano-photonics.

The objective of the thesis is to study the influence of a nano-antenna (plasmonic or magnetic) on the intersystem crossing rate of a single fluorescent molecule.



When a fluorescent molecule is optically pumped, an electron goes from the ground singlet state to an excited singlet state. The electron thus promoted can then follow different relaxation paths: radiative (emission of a fluorescence photon), non-radiative (giving its energy directly to the environment), but it can also go into a triplet state which is generally dark. This passage is called intersystem crossing.

Thanks to a measurement protocol based on the simultaneous monitoring of the photon flux over time and anticorrelation measurements, it is possible to go back to the different rates governing the photophysics of the molecule, and in particular the transition from the singlet state into the triplet state.



The thesis will take place in two main parts:

- Robust functionalization of an atomic force microscope tip by a nanoparticle.

- Optical measurements on a single molecule in the presence and absence of the nanoparticle to obtain a quantitative measurement of the influence of the nanoparticle.

In addition to the usual training in scientific work, the skills developed during the thesis will be the following:

- Atomic force microscopy

- Micro / nanofabrication

- Optical microscopy and spectroscopy on single objects

- Quantum optics with single photons

- Nanophotonics



The candidate must be a graduate of an engineering school or a research master, preferably in nanoscience. He must have a strong taste for experimental physics. Previous experience in microscopy / spectroscopy, and / or in clean room manufacturing will be a plus.
Encapsulated profluorescent molecules for radioactive trace detection for nuclear dismantling

SL-DRF-20-0385

Research field : Radiation-matter interactions
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l’Energie

Laboratoire Interdisciplinaire sur l’Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Jean-Philippe RENAULT

Thierry LEGALL

Starting date : 01-09-2020

Contact :

Jean-Philippe RENAULT
CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 50

Thesis supervisor :

Thierry LEGALL
CEA - DRF/JOLIOT/SCBM/LCB / Chimie Bioorganique

01 69 08 71 05

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=jrenault

Laboratory link : http://iramis.cea.fr/nimbe/lions/

Electronic excitations of borophene: novel graphical tool for the electron density

SL-DRF-20-0552

Research field : Radiation-matter interactions
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Francesco SOTTILE

Starting date : 01-10-2020

Contact :

Francesco SOTTILE
Ecole Polytechnique - UMR 7642

0169334549

Thesis supervisor :

Francesco SOTTILE
Ecole Polytechnique - UMR 7642

0169334549

Personal web page : https://etsf.polytechnique.fr/People/Francesco

Laboratory link : https://etsf.polytechnique.fr

To describe, analyze and predict the effects of electronic excitations and the related changes in the electronic density is of paramount importance, both for the understanding of materials' properties and for designing functionalities in new frontiers applications. The density fluctuations are directly related to important physical concepts like plasma oscillations, the ideal bridge between classical physics, as described by the Maxwell equations, and quantum phenomena, like plasmonics.



In this thesis project, we propose to build an intuitive approach for the analysis of electronic excitations, based on the accurate determination and visualization of the electron density in real space and time. This will constitute a new tool for the description of electronic properties of materials. In the linear response regime, it requires complete knowledge of the polarizability. This goes well beyond the state-of-the art of calculations of spectra such as optical absorption, where only the macroscopic component is needed. We propose to develop this new tool to study the plasmonic features of borophene (single atomic plane of boron atoms), a novel 2D structure with unique features including unusual polymorphism and anisotropy, metallicity and transparency, flexibility and superconductivity.

SL-DRF-20-0386

Research field : Radiation-matter interactions
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l’Energie

Laboratoire Interdisciplinaire sur l’Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Jean-Philippe RENAULT

Geraldine CARROT

Starting date : 01-09-2020

Contact :

Jean-Philippe RENAULT
CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 50

Thesis supervisor :

Geraldine CARROT
CEA - DRF/IRAMIS/NIMBE/LICSEN

01 69 08 41 47

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=jrenault

Laboratory link : http://iramis.cea.fr/nimbe/lions/

Fluorescence detection for remote discriminating chemical dosimetry of aplha and beta sources

SL-DRF-20-0390

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Saclay

Contact :

Gérard BALDACCHINO

Starting date : 01-10-2020

Contact :

Gérard BALDACCHINO
CEA - DRF/IRAMIS/LIDYL

01 69 08 57 02

Thesis supervisor :

Gérard BALDACCHINO
CEA - DRF/IRAMIS/LIDYL

01 69 08 57 02

Personal web page : http://iramis.cea.fr/Pisp/gerard.baldacchino/

Laboratory link : http://iramis.cea.fr/LIDYL/dico/

In the context of the Sanitation and Decommissioning of nuclear installations, it is important to locate very quickly alpha, beta and gamma source terms on the surfaces that can be treated, isolated and removed from the site in a regulated way. Gamma imaging is a technique that works very well now. On the other hand, the alpha or beta sources are localizable only in contact with materials, on the surface, because these emissions do not propagate over distances of more than a few cm. Fluorescence dosimetry and chemical scavenging during radiolysis processes have made tremendous progress recently. This allowed for example to highlight the effects of ionization density and Linear Energy Transfer (TEL effect) in radiolysis of water by heavy ions and alpha. Beta and alpha found in nuclear have very different TEL leading to very different yields of free radical production (H, OH, hydrated electron, HO2) and molecules (H2, H2O2), resulting from the ionization of the water. The objective of the proposed thesis is to exploit these differences by using non-toxic chemical sensors producing a fluorescent molecule detectable at long distance (objective, several meters), under laser illumination. Starting from the known chemical mechanisms, the doctoral student will have to give the experimental and applied conditions (on site) allowing the acquisition of images exploitable quickly.
Optimization of the plasmonic hot electrons emission from metallic nanoobjects for targeted photodynamic oncological therapies

SL-DRF-20-0295

Research field : Radiation-matter interactions
Location :

Service de Physique de l’Etat Condensé

Laboratoire d’Electronique et nanoPhotonique Organique

Saclay

Contact :

Ludovic DOUILLARD

Starting date : 01-10-2020

Contact :

Ludovic DOUILLARD
CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 36 26

Thesis supervisor :

Ludovic DOUILLARD
CEA - DRF/IRAMIS/SPEC/LEPO

01 69 08 36 26

Personal web page : http://iramis.cea.fr/Pisp/ludovic.douillard/

Laboratory link : http://iramis.cea.fr/spec/LEPO/

The interaction of a metal nanoparticle with an ultrashort laser light pulse is accompanied by an emission of hot electrons of interest for biomedical applications, especially in targeted oncology therapies. Related to the occurrence of plasmon resonances of a metal nanoparticle, this emission of hot electron manifests itself in the transparency wavelength window of the human body (red 700 nm - near infrared 1500 nm) thus allowing a wide therapeutic access. In biological environment, this electronic emission generates locally reactive oxygen species (ROS) in a micrometer radius around the source. These ROS species are the source of an important oxidative stress for the cells and are the driving agents of phototherapies under development.



The objective of this work is to optimize the production of hot electrons by a sub-wavelength metal object for photothermal and photodynamic therapies applied to breast cancer. It is an experimental work in close collaboration with a relevant partnership of physicists, chemists, biologists and oncologists (CEA, CentraleSupélec, ENS Paris Saclay, AP-HP Avicenne Hospital). It will benefit from the experience acquired by the CEA IRAMIS SPEC group in LEEM / PEEM (Low Energy Electron / PhotoEmission Electron Microscopy) microscopy, the principle of which is based on the monitoring of the distribution of electrons emitted in response to a plasmon resonance. This technique makes it possible to determine, at the scale of the individual object, the temporal dynamics of the emission of electrons, and their spatial as well as energetic distributions through their kinetic energy spectra.



Within the INSERM Plan Cancer HEPPROS project, the targeted nanoobjects optimized for an efficient emission of hot electrons, are then further covered by a biocompatible polymer for in vitro and in vivo studies on tumours of the Avicenne Hospital tumour library.



Keywords: hot electrons, oncology, phototherapy, plasmon, laser, LEEM-PEEM.



[Douillard 2017, 2012, 2011] S. Mitiche et al. J. of Phys. Chem. C 121 (2017) 4517–4523, C. Awada, et al. J. of Phys. Chem. C 16 (2012) 14591, L. Douillard, F. Charra. J. of Phys. D: Applied Physics 44 (2011) 464002, C. Hrelescu, et al. Nano Lett. 11 (2011) 402–407



Laboratoire d’accueil CEA IRAMIS SPEC UMR 3680

Correspondant CEA chargé du suivi de la thèse ludovic.douillard@cea.fr

Ecole doctorale Ondes et Matière, Univ. Paris Saclay.

SL-DRF-20-0545

Research field : Radiation-matter interactions
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l’Energie

Laboratoire Interdisciplinaire sur l’Organisation Nanométrique et Supramoléculaire

Saclay

Contact :

Jean-Philippe RENAULT

Daniel Camparat

Starting date : 01-09-2020

Contact :

Jean-Philippe RENAULT
CEA - DRF/IRAMIS/NIMBE/LIONS

01 69 08 15 50

Thesis supervisor :

Daniel Camparat
Université Paris Saclay / Laboratoire Aimé Cotton - UMR 9188


Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=jrenault

Laboratory link : http://iramis.cea.fr/nimbe/lions/

Development of an integrated high-sensitivity polymer into a remotely readable wireless gamma dosimeter

SL-DRF-20-0610

Research field : Radiation-matter interactions
Location :

Centre de recherche sur les Ions, les Matériaux et la Photonique

Centre de recherche sur les Ions, les Matériaux et la Photonique

Saclay

Contact :

Yvette NGONO-RAVACHE

Starting date : 01-10-2020

Contact :

Yvette NGONO-RAVACHE
CEA - DRF/IRAMIS/CIMAP/CIMAP

02 31 45 47 51

Thesis supervisor :

Yvette NGONO-RAVACHE
CEA - DRF/IRAMIS/CIMAP/CIMAP

02 31 45 47 51

Personal web page : http://iramis.cea.fr/Phocea/Membres/Annuaire/index.php?uid=ngono

Laboratory link : http://cimap.ensicaen.fr/spip.php?rubrique17

Dosimetric monitoring in decommissioning activities is of the first importance. In order to overcome the limitations of currently available dosimeters, new passive real-time wireless dosimeters are developed. They are based on the frequency variation of a microwave resonator induced by the overpressure resulting from the radiation-induced gas emission of the polymer placed in the cavity. Commercial polyethylenes (PE) currently used in theses dosimeters are of variable compositions and their out-gassing levels involve the use of high masses of polymers, thus high cavity filling ratios, at low doses (1-100 kGy) leading to poor reproducibility. The aim of this thesis is to develop a highly radiosensitive polymer leading to high reproducibility, reliability and sensitivity sensors at low doses; by inserting nanometric inclusions of high Z metal atoms (in metallic or organometallic form) into PE, in order to triple its gas emission efficiency. The PhD student will be responsible for: 1) selecting the most suitable atom between Pt and Au and the most suitable chemical form, on the basis of the literature and with the help of ab-initio modeling, 2) synthesize or chemically modify PE materials containing inclusions of so selected compounds at various concentrations, 3) characterize them and 4) study their behavior under gamma radiations (gaseous emission and macromolecular defects) in order to extract the most emissive.
Influence of irradiation on infrared optical properties of ZnGeP2

SL-DRF-20-1103

Research field : Radiation-matter interactions
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Valérie VENIARD

Starting date : 01-10-2020

Contact :

Valérie VENIARD
CNRS - LSI/Laboratoire des Solides Irradiés

01 69 33 45 52

Thesis supervisor :

Valérie VENIARD
CNRS - LSI/Laboratoire des Solides Irradiés

01 69 33 45 52

Personal web page : https://etsf.polytechnique.fr/People/Valerie

Laboratory link : https://portail.polytechnique.edu/lsi/fr/recherche/spectroscopie-theorique

The compound ZnGeP2, in its monocrystalline form, is a remarkable and very promising material in the infrared optical range: it is transparent between 1 and 8 microns and, because of its positive birefringence, it has very effective nonlinear optical properties.



Improving the transparency properties in the IR domain of this material is therefore a scientific and technical challenge. However, the presence of defects comes from absorption bands induced during the synthesis, limiting its physical properties. Irradiation could be a new way to change the nature and concentration of the defects responsible for the absorption process in this compound.



The objective of these thesis is therefore to define the optimal irradiation conditions in terms of fluence, nature and energy of the particles, irradiation temperature, to improve the properties in the IR domain. To this end, a quantitative method such as Electron paramagnetic resonance will be used to determine the mechanisms of production of irradiation defects and their interaction with the defects resulting from the synthesis.
Generation of XUV attosecond pulses for the real-time study of ultrafast gas ionization

SL-DRF-20-0601

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique (ATTO)

Saclay

Contact :

Pascal SALIERES

Starting date : 01-10-2020

Contact :

Pascal SALIERES
CEA - DRF/IRAMIS/LIDyL/ATTO

0169086339

Thesis supervisor :

Pascal SALIERES
CEA - DRF/IRAMIS/LIDyL/ATTO

0169086339

Personal web page : http://iramis.cea.fr/Pisp/pascal.salieres/

Laboratory link : http://iramis.cea.fr/LIDYL/atto/

More : http://attolab.fr/

Summary :

The student will first generate XUV attosecond pulses using an intense Titanium:Sapphire laser (ATTOLab Excellence Equipment), and then use them to investigate the ionization dynamics of atomic and molecular gases: electron ejection, electronic rearrangements in the ion, charge migration…



Detailed summary :

Recently, the generation of sub-femtosecond pulses, so-called attosecond pulses (1 as=10-18 s), has made impressive progress. These ultrashort pulses open new perspectives for the exploration of matter at unprecedented timescale. Their generation result from the strong nonlinear interaction of short intense infrared (IR) laser pulses (~20 femtoseconds) with atomic or molecular gases. High order harmonics of the fundamental frequency are produced, covering a large spectral bandwidth in the extreme ultraviolet (XUV) range. In the temporal domain, this coherent radiation forms a train of 100 attosecond pulses [1]. In order to generate isolated pulses, it is necessary to confine the generation in an ultrashort temporal window, which implies the development of various optical confinement techniques.



With such attosecond pulses, it becomes possible to investigate the fastest dynamics in matter, i.e., electronic dynamics that occur naturally on this timescale. Attosecond spectroscopy thus allows studying fundamental processes such as photo-ionization, in order to answer questions such as: how long does it take to remove one electron from an atom or a molecule? The measurement of such tiny ionization delays is currently a “hot topic” in the scientific community. In particular, the study of the ionization dynamics close to resonances gives access to detailed information on the atomic/molecular structure, such as the electronic rearrangements in the remaining ion upon electron ejection [2].



The objective of the thesis is first to generate attosecond pulses with duration and central frequency adequate for the excitation of various atomic and molecular systems. The objective is then to measure the instant of appearance of the charge particles, electrons and ions. Finally, the measurement of the photoelectron angular distribution, in combination with the temporal information, will allow the reconstruction of the full 3D movie of the electron ejection.

The experimental work will include the development and operation of a setup installed on the FAB1 laser of the ATTOLab Excellence Equipment allowing: i) the generation of attosecond XUV radiation, ii) its characterization using quantum interferometry, iii) its use in photo-ionization spectroscopy. The theoretical aspects will also be developed. The student will be trained in ultrafast optics, atomic and molecular physics, quantum chemistry, and will acquire a good mastery of charged particle spectrometry. A background in ultrafast optics, nonlinear optics, atomic and molecular physics is required.

Part of this work will be performed in collaboration with partner French and European laboratories through joint experiments in the different associated laboratories (Milano, Lund).



References :

[1] Y. Mairesse, et al., Science 302, 1540 (2003)

[2] V. Gruson, et al., Science 354, 734 (2016)
Studying quantum decoherence in photoionization with attosecond spectroscopy and artificial intelligence

SL-DRF-20-1162

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique (ATTO)

Saclay

Contact :

Pascal SALIERES

Starting date : 01-10-2020

Contact :

Pascal SALIERES
CEA - DRF/IRAMIS/LIDyL/ATTO

0169086339

Thesis supervisor :

Pascal SALIERES
CEA - DRF/IRAMIS/LIDyL/ATTO

0169086339

Personal web page : http://iramis.cea.fr/Pisp/pascal.salieres/

Laboratory link : http://iramis.cea.fr/LIDYL/ATTO/

More : http://attolab.fr/

For the past ten years, the generation of attosecond pulses has made it possible to study the fastest dynamics in matter, those associated with electrons, which take place naturally on this timescale. Attosecond spectroscopy thus allows the study of fundamental processes such as photoionization. In particular, studying the coherence of the ionization dynamics would provide access to very fine information on the atomic / molecular structure, such as electronic rearrangements in the ion following the ejection of an electron.



The objective of the thesis is to measure the complete quantum state of an electronic wave packet obtained after the photoemission. Experimentally, the student will study the coherence of the ionization dynamics of atomic and molecular gases using attosecond pulses generated from an intense Titanium:sapphire laser (ATTOLab Excellence Equipment). Theoretically, he / she will implement digital tools allowing the extraction of the quantum state of the photoelectron from experimental measurements.

 

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