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PhD subjects

9 sujets IRAMIS

Dernière mise à jour : 17-09-2019


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• Radiation-matter interactions

 

SL-DRF-19-0432

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 :

Marie GELEOC

Jean-Philippe RENAULT

Starting date : 01-09-2019

Contact :

Marie GELEOC
CEA - DRF/IRAMIS/LIDyL/SBM


Thesis supervisor :

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

01 69 08 15 50

Personal web page : http://iramis.cea.fr/Pisp/marie.geleoc/

Laboratory link : http://iramis.cea.fr/lidyl/sbm/

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

SL-DRF-19-1103

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

Starting date : 01-10-2019

Contact :

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

01 69 08 15 50

Thesis supervisor :

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

01 69 08 15 50

Attosecond pulses generated in activeoptical gratings: experiments, theory and applications

SL-DRF-19-0487

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique

Saclay

Contact :

Thierry Ruchon

Starting date : 01-10-2019

Contact :

Thierry Ruchon
CEA - DRF/IRAMIS/LIDyL/ATTO

0169087010

Thesis supervisor :

Thierry Ruchon
CEA - DRF/IRAMIS/LIDyL/ATTO

0169087010

Personal web page : http://iramis.cea.fr/LIDYL/Pisp/thierry.ruchon/

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

Light in the extreme ultraviolet (XUV) is a universal probe of mater, may it be in diluted or condensed phase: photons associated with this spectral range carry energy of 10 to 100 eV, sufficient to directly ionize atoms, molecules or solids. Large scale instruments such as synchrotrons or the lately developed free electron lasers (FEL) work in this spectral range and are used to both study fundamental light matter interaction and develop diagnosis tools. However these instruments do not offer the temporal resolution require to study light matter interactions at their ultimate timescales, which is in the attosecond range (1as = 10-18s). An alternative is offered by the recent development of XUV sources based on high order harmonic generation (HHG). They are based on the extremely nonlinear interaction of a femtosecond intense laser beam with a gas target. Our laboratory has pioneered the development, control and design of these sources providing XUV attosecond pulses.



During this PhD project, we will develop specific setups putting at play two beams forming an active grating to generate attosecond pulses with controlled angular momenta, may it be spin or orbital angular momenta. This will open new applications roads through the observations of currently ignored spectroscopic signatures. On the one hand, the fundamental aspects of the coupling of spin and orbital angular momentum of light in the highly nonlinear regime will be investigated, and on the other hand, we will tack attosecond novel spectroscopies, may it be in diluted or condensed phase. In particular, we will chase helical dichroism, which manifest as different absorptions of beams carrying opposite orbital angular moments. These effects are largely ignored to date.

The student will acquire practical knowledge about lasers, in particular femtosecond lasers, and hands on spectrometric techniques of charged particles. He/she will also study strong field physical processes which form the basis for high harmonic generation. He/she will become an expert in attosecond physics. The acquisition of analysis skills, computer controlled experiments skills will be encouraged although not required.



Detailed presentation of the subject : http://iramis.cea.fr/LIDYL/Pisp/thierry.ruchon/

Irradiation effects on the infrared optical properties of ZnGeP2

SL-DRF-19-0056

Research field : Radiation-matter interactions
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Jérémie Lefevre

Bruno BOIZOT

Starting date : 01-10-2019

Contact :

Jérémie Lefevre
Ecole Polytechnique - Laboratoire des Solides Irradiés

01 69 33 45 30

Thesis supervisor :

Bruno BOIZOT
CEA - DRF/IRAMIS/LSI/LSI

01 69 33 45 22

Personal web page : https://www.polytechnique.edu/annuaire/fr/users/bruno.boizot

Laboratory link : https://portail.polytechnique.edu/lsi/fr/recherche/defauts-desordre-et-structuration-de-la-matiere

The ZnGeP2 compound, in its monocrystalline form, is a remarkable and very promising material for infrared optical applications: it is transparent between 1 and 8 µm and, due to its positive birefringence, it has highly-effective nonlinear optical properties.



The improvement of transparency properties in the infra-red (IR) domain of this material is thus both a scientific and technical challenge. However, defects coming from the synthesis processes induce absorption bands in the IR range, thus limiting the physical properties of this compound. Irradiation could be a new way for changing the nature and the content of defects responsible of this absorption in the IR domain.



The goal of the PhD is therefore to define the irradiation conditions (fluences, beam energy, irradiation temperature ...) for improving the IR properties of irradiated ZnGeP2. For that purpose, a quantitative spectroscopic tool like Electron Paramagnetic Resonance spectroscopy will be used in order to determine the mechanisms of irradiation defects production and their interactions with the defects produced during the pulling of ZnGeP2 crystals.
Ultra relativistic plasmonic

SL-DRF-19-0725

Research field : Radiation-matter interactions
Location :

Laboratoire des Solides Irradiés

Laboratoire des Solides Irradiés

Saclay

Contact :

Michèle RAYNAUD

Starting date : 01-10-2019

Contact :

Michèle RAYNAUD
CEA - DRF/IRAMIS/LSI/LSI


Thesis supervisor :

Michèle RAYNAUD
CEA - DRF/IRAMIS/LSI/LSI


Personal web page : http://www.polytechnique.edu/annuaire/fr/users/michele.raynaud-brun

Laboratory link : https://portail.polytechnique.edu/lsi/fr/recherche/theorie-de-la-science-des-materiaux/plasmonique-lechelle-quantique

The present PHD work aims at exploring theorically and numerically the generation of fast electron beams in relativistic laser-solid interaction by using properly-structured targets whose surface characteristics allow SPW excitation or local electromagnetic modes in regimes of laser intensity ranging above 10^21 W/cm2. The “upgrading” of Relativistic Plasmonics physics toward intensity regimes of magnitude larger than the typical values used in ordinary plasmonics, and such that nonlinear and relativistic effects play a major role is of fundamental interest for the physics of relativistic plasmas. It may also lead to groundbreaking ultra-short synchronized light and electron sources with applications in probing ultrafast electronic processes. In this context, this theoretical and numerical study will allow to suggest new experimental schemes feasible on the Apollon facility and multi-PW lasers.
Quantum fragmentation in frustrated magnets

SL-DRF-19-0538

Research field : Radiation-matter interactions
Location :

Laboratoire Léon Brillouin

Groupe 3 Axes

Saclay

Contact :

SYLVAIN PETIT

ELSA LHOTEL

Starting date : 01-10-2018

Contact :

SYLVAIN PETIT
CEA - DRF/IRAMIS

01 69 08 60 39

Thesis supervisor :

ELSA LHOTEL
CNRS - Insitut Néel

04 76 88 12 63

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

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

Magnetic frustration is one of the modern routes in condensed matter physics leading to the discovery of new states of matter. The “spin ice” and more generally, the “Coulomb phases” are celebrated examples of this physics. In contrast with classical magnetically ordered phases, these states remain disordered down to the lowest temperatures, yet form a correlated paramagnet with specific spin-spin correlations. In this context, a new concept has been recently proposed, called “magnetic fragmentation” [PRX 4, 011007 (2014)]. This is an original state where the magnetic moment fragments into two sub-fragments: one of them forms an antiferromagnetic phase with a reduced ordered moment, while the other keeps fluctuating and forms a Coulomb phase.



In combining magnetization measurements, elastic and inelastic neutron scattering experiments, we have shown that the pyrochlore compound Nd2Zr2O7 could be a realization of this theory [1,2], even if experimental evidences suggest that still not understood quantum phenomena are at play.



This thesis work aims at understanding the origin of fragmentation in this system. We especially plan to determine its stability range by studying doped samples. Actually, replacing part of the Zirconium (Zr) by Titanium (Ti), or Neodymium (Nd) by Lanthanum (La), magnetic interactions can be modified. Varying the substitution, we will explore the phase diagram and probe the possible existence of a quantum critical point predicted by theory. The complementarity between macroscopic and neutron scattering measurements is one of the key points to determine the quantum Hamiltonian and beyond, understand the microscopic mechanisms of magnetic fragmentation, along with the nature of the spin dynamics that emerge from this peculiar ground state.



The thesis work will take place in France both at the Institut Néel (Grenoble) and at LLB (Saclay). It consists in measuring both the magnetization and specific heat down to base temperature (100 mK) (Institut Néel) and to finely determine the magnetic structures as well as the spin excitations spectrum by the different neutron techniques. The latter will be carried out at LLB (Saclay) and at ILL (Grenoble). A large part of the data analysis will be based on numerical simulation tools. Most of them exist today but may be further developed.

Physics and applications of hot electrons of plasmonic origin

SL-DRF-19-0347

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 : 01-10-2019

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/

At small scale, the interaction of light with a metallic object results in the occurrence of remarkable resonances within the absorption spectrum, the plasmon resonances. These resonances correspond to collective oscillations of the charge carriers [Mie 1908] and constitute a research domain in itself known as Plasmonics. Beyond its interest in the manipulation of the near optical field, a metal object at plasmonic resonance is a source of hot electrons whose electronic properties can be used to achieve non classical chemistry reactions at the local scale.



This work aims to study the fundamental physics of the emission of hot electrons by a nanometric metallic object in connection with applications, particularly medical ones such as the anticancer photodynamic therapies. It is a work of experimental character in close collaboration to a relevant partnership of physicists, chemists, biologists and oncologists from different Institutions (CEA, CentraleSupélec, Hospital Saint-Louis). It will benefit from the experience acquired by the CEA IRAMIS SPEC group in LEEM / PEEM (Low Energy Electron / PhotoEmission Electron) microscopies, the principle of which is based directly on the acquisition of the distribution of the photoelectrons emitted in response to a plasmon resonance decay [Douillard 2017, 2012, 2011] and is therefore a unique technique of choice for this study.



The objectives are to answer fundamental questions related to the emission of hot electrons by a metallic particle under ultrafast multiphoton optical excitation. In particular, this involves determining the emission dynamics of the charge carriers (pump probe experiment) and their physical distributions: spatial mapping of the emission hot spots at the nano-object scale and energy mapping through the determination of the kinetic energy spectra. The ultimate goal takes place in the context of a project devoted to medical oncology (breast cancer) and more specifically on the optimization of anticancer therapies under development, namely the photothermal and photodynamic therapies.



Keywords: hot electrons, plasmon, laser, PEEM, LEEM
Plasma Mirrors 'on-chip': "Towards extreme intensity light sources and compact particle accelerators"

SL-DRF-19-0633

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Physique à Haute Intensité

Saclay

Contact :

Henri VINCENTI

Guy BONNAUD

Starting date : 01-10-2019

Contact :

Henri VINCENTI
CEA - DRF/IRAMIS/LIDyL/PHI

0169080376

Thesis supervisor :

Guy BONNAUD
CEA - DRF/IRAMIS/LIDyL/PHI

0169088140

Personal web page : http://iramis.cea.fr/Pisp/henri.vincenti/

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

More : https://picsar.net

Attosecond optoelectronics in semiconductors

SL-DRF-19-1100

Research field : Radiation-matter interactions
Location :

Service Laboratoire Interactions, Dynamique et Lasers

Attophysique

Saclay

Contact :

Hamed MERDJI

Starting date : 01-10-2019

Contact :

Hamed MERDJI
CEA - DRF/IRAMIS/LIDyL/ATTO

0169085163

Thesis supervisor :

Hamed MERDJI
CEA - DRF/IRAMIS/LIDyL/ATTO

0169085163

Personal web page : http://iramis.cea.fr/LIDYL/Pisp/hamed.merdji/

Laboratory link : http://iramis.cea.fr/LIDYL/Phocea/Page/index.php?id=99

Ultrafast nano-photonics science is emerging thanks to the extraordinary progresses in nano-fabrication and ultrafast laser science. Boosting extremely intense electric fields in nano-structured photonic devices has the potential of creating nano-localized sources of energetic photons or particles opening vast applications in science and in the industry. Optoelectronic is extending to the highly non-linear regime and frequencies reaching the petahertz domain. A recent impact of this capability of controlling the response of above band gap electrons under strong fields is the emergence of high harmonic generation (HHG) in crystal [1-6]. 2D and 3D semiconductors exhibits properties of high electron mobility that allows to drive intense electrons currents coherently in the conduction band. HHG are emitted when those electrons recombine to the valence band and are thus an excellent observable of the attosecond/petahertz dynamics. This is a pure above band gap non-perturbative phenomena which occurs efficiently in a few 10s to 100s nanometer exit layer of a crystal and down to an atomically thin layer [5,6]. The strong electron current from which HHG originate can be manipulated in space and time. The project will focus in the strong localization in space, and time, at the single optical cycle scale [7,8], of the petahertz electron current. This control can not only revolutionize attosecond science but also prepare a new generation of petahertz opto-electronic devices. Based on the CEA group expertise, experimental and theoretical resources [9-12], the fellow will seek for efficient ways to boost the interaction regime through plasmonic amplification and field confinement for the integration of novel optolectronic devices. A specific focus will be on 2D materials like graphene, MoS2 and h-BN. Attosecond pulse generation will also be investigated by using harmonic phase measurements available at CEA (RABBITT, FROG techniques). We will also develop an original nanostructured sample that will allow to control the attosecond electron current.

 

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