Offres de Post doctorat
Postdoctoral position : Mid-Infrared Metamorphic Interband Cascade Vertical cavity Surface Emitting Laser
Addressing individual ferromagnetic nano-objects for magneto-transport measurements
Postdoctoral position : Mid-Infrared Metamorphic Interband Cascade vertical cavity Surface Emitting Laser
Group: Photonics, LAAS-CNRS, Toulouse, France
The availability of electrically pumped VCSELs at wavelength longer than 3 µm is considered as a breakthrough for laser-based optical sensing applications. Indeed, these devices have a low cost potential, low power consumption and overall emits single frequency with mode-hop free tunability. These ideal and unmatched properties will enable widespread utilization of photonic sensor networks. This will contribute to the well being and health of the population by stimulating air pollution monitoring, detecting leaks and preventing fire as other possible application.
Electrically-pumped mid-IR VCSELs rely on GaSb-based materials. But entering in the 3-5 µm wavelength range requires new approaches for both active zone design and device processing. Thus, the structure will be based on an interband cascade type-II active zone, a metamorphic oxide-based lateral confinement scheme and a hybrid-mirror technology with target performances suited for spectroscopy applications.
The starting point of this project funded by the French ANR agency is the complementary know-how of the consortium with the expertise of IES on the growth and study of GaSb-based VCSELs, the LAAS for VCSELs processing, in particular regarding the controlled oxidation of Al(Ga)As layers, and of FOTON for their expertise in dielectric materials dedicated to Bragg mirror.
The main objectives of this Post-Doc are:
- to develop practical simulation tools, essential for the optical and electrical design of the MIR-VCSEL devices. This design worktask will be led in close collaboration with the FOTON team to consider the thermal behaviour.
- to take over the technological fabrication of electrical pumped ridge lasers and VCSELs , through developing and entrench the process steps up to developing a complete reliable process flow.
- to characterize test laser structures and VCSEL devices, enabling a feedback loop for improving the design and fabrication steps.
Requirements: The candidate must have a PhD and should have a solid practical background on the technologies used in cleanroom environment for the processing of III-V based optoelectronic devices. A strong knowledge of the physics and design of optoelectronic component, specifically vertical cavity lasers, is also required.
Starting date: as of now
Duration: 12-24 months
Monthly net salary: 2200 €
Applicants should send:
- a resume/bio
- pointers to their most important publications and/or their PhD (Please only French or English documents)
- recommendation letter(s)
Contact person: Guilhem ALMUNEAU 05 61 33 64 73 firstname.lastname@example.org
Addressing individual ferromagnetic nano-objects for magneto-transport measurements
Laboratoire de Physique et Chimie des Nano-Objets, Toulouse
One year post-doctoral position starting in January 2018.
The major goal of our project is the investigation of the electronic and magnetic properties of individual single crystalline ferromagnetic Co nanorods (diameter of 6-7 nm, length of 70-100 nm) and Fe nanocubes (8 - 25 nm edge) elaborated by chemical routes. Until now, electronic and magnetic studies of those magnetic nano-objects (MNO) are carried on assemblies which not allow to probe their intrinsic properties. Even in highly diluted systems we have shown that the dipolar interactions hide the intrinsic magnetic anisotropy . Thus, in order to probe individual MNO, we propose:
- to develop individual MNO addressing techniques under controlled atmosphere using an electrospray apparatus inserted in a glove box.
- to probe the MNO electronic and magnetic properties thanks to magneto-transport measurements at different temperatures (300K-4K) and magnetic field orientation (up to 9T) on one or few MNO trapped between two metallic electrodes.
Concerning the first point, a preliminary work made at the LPCNO has shown the possibility to depose individual MNO (Fe nano-cubes and FeCo nano-sphere) on a SiO2/Si substrate by using an electrospray . It consists in injecting a colloidal solution of MNO into a capillary put at a very high voltage. At the end of the capillary, because of high electrostatic repulsion, mono disperse micro-droplets are emitted into a vacuum chamber where the substrate is inserted. The micro-droplets undergo several Coulomb explosions into the vacuum chamber and form, before reaching the sample, a spray of individual MNO. This technique has to be improved, especially, the deposition parameters and the electrospray apparatus has to be installed into a glove box and coupled with an electro valve allowing to perform sequential deposition.
Concerning the second point, our objective is to connect individual MNO in a transistor configuration between two metallic electrodes, using the Si substrate as a back-gate. To do this, we need to fabricate metallic electrodes separate by a nano-gap ranging from 10nm to 50nm. Recently we develop a process allowing us to fabricate nanogap down to 20-30nm, however the yield is low. The process has to be improved in order to reach 10 nm gap to connect Fe nanocubes.
The development and optimization of those two points should allow us to monitor in real time the trapping of individual or few MNO between the metallic electrodes by measuring the current passing through the metallic electrodes as it has been shown by  with a similar set-up.
The postdoc will be in charge of the optimization of the electrospray set-up, especially the installation and instrumentation of the electro-valve. He (she) also will work in close collaboration with chemists in order to improve the preparation of the colloidal solution of MNO. He (she) will be also in charge of the nanofabrication and he (she) will optimize the nanogap process. Then he (she) will develop the protocol allowing to monitor in real time the trapping of MNO between two metallic electrodes.
Candidates should be experimentalists with good skills in physics, micro-nanofabrication and chemistry. Please send resume, publications list and motivation letter.
Benjamin Lassagne (email@example.com
Marc Respaud (firstname.lastname@example.org)
 M. Respaud et al (in preparation)
 P. Agostini et al. J. Nanopart. Res. 18 11 (2016)
 Y. Qian et al. ACS Nano. 7 1487 (2013)
This position is linked to a research project funded by the civil aviation administration in France, coordinated by the LATECOERE company located in Toulouse. This project aims at developing an assistance system for the control of an aircraft in airport areas, provided overall for bad visibility conditions (night, fog, rain…); multi-spectral images are acquired, fused and analyzed in order to create a view both synthetic and realistic of the environment where the aircraft is navigating. This view, augmented by symbolic and textual information, is sent to a monitor in the cockpit, in order to inform the pilot about all potential risk when he controls the aircraft from the parking area until the runway, and reciprocally.
The applicant will be integrated in the RAP research team (Robotics, Action and Perception) in the Robotics department of LAAS-CNRS.
The applicant will participate to the design of the architecture of the heterogeneous system (FPGA, CPU, DSP…) with respect to a functional specification and to critical real-time constraints. An SME partner of the project will develop the hardware system.
The applicant will have also to understand the image processing algorithms developed in the prototyping step, so that he could propose optimizations required for their implementation on the embedded architecture satisfying the real time constraints.
He will be responsible for the technical management of the project (doc, source code…), for the deliverables and for the technological transfer respecting the rules defined in the project.
With the involved permanent researchers of the RAP team, he will supervise the work of two PhD students or engineers funded by the project for the algorithmic development: image enhancement, filtering, fusion, and interpretation in order to detect objects typical from airport areas. He will guide the choice of these algorithms with respect to their migration on the physical system, specifically to take advantage from the processing parallelism. He will participate and will coordinate the algorithm migration on the system.
He will participate to the validation works supervised by the project coordinator and by aircraft companies. Validations will be done either with simulations (using HIL method) or in real conditions with a system embedded on an aircraft or a vehicle navigating on the taxiways of an airport.
Finally the applicant will have to interact with the project partners, preparing formal presentations for internal meetings and workshops. He will also participate to the scientific dissemination with the RAP permanent researchers.
- WORK TO BE DONE
- State of the art and contributions on the match between physical architecture and algorithms for real-time vision.
- Monitoring of the algorithmic development in C/C++
- Low level optimization and migration of algorithms on a heterogeneous architecture selected to respect real-time constraints.
- Hardware specification (operators, memories, bus, etc)
- Project management (doc, source code, meetings, etc)
Applicants must have a PhD in embedded system, electronics…
All of some of these competences will be appreciated:
- Autonomy, team work, supervision
- Project management and communication
- Algorithms for real time vision (OpenCV, Matlab), with basic knowledge in projective geometry (camera model, calibration, homography…)
- Embedded software development (C, optimization SIMD NEON)
- Hardware development (VHDL, Xilinx Vivado, test-bench programming)
- Migration of real-time vision algorithms on heterogeneous architectures FPGA+CPU.
- Methodology for the design of heterogeneous system.
One year contract extended at least one year
- CONTACT :
Michel Devy : email@example.com, +33 5 61 33 63 31
Jonathan Piat : firstname.lastname@example.org, +33 5 61 33 63 44
Optimization of coupled opto-electronic oscillators
Micro-ondes et Opto-micro-ondes pour systèmes de Télécommunications
Responsables du contrat : Olivier LLOPIS / Arnaud FERNANDEZ
Mots clefs : optique-micro-ondes, lasers à modes verrouillés, oscillateur micro-onde, optique fibrée, bruit de phase, peignes de fréquence optique, ondes millimétriques
Le LAAS est impliqué actuellement sur l’étude d’un système de génération de signaux micro-ondes et millimétriques utilisant un laser fibré à modes verrouillés. Il s’agit plus précisément d’une approche COEO (Coupled Opto-Electronic Oscillator), c’est-à-dire du couplage d’un oscillateur micro-onde et d’un oscillateur optique qui partagent le même résonateur (optique). L’objectif de ce séjour post-doctoral est double : d’une part valoriser et améliorer les performances du COEO 10 GHz développé au LAAS, et assurer son transfert vers notre partenaire industriel local OSAT et, d’autre part, de monter en fréquence en gamme millimétrique à partir d’un deuxième dispositif utilisant une fréquence fondamentale à 30 GHz et susceptible de générer des harmoniques bien au-delà de 100 GHz. Dans un premier temps, on étudiera en particulier les moyens d’accorder la fréquence RF de sortie du COEO et de réduire l’effet des vibrations sur les composants fibrés (bobines de fibre en particulier). Ce premier travail a un objectif proche de la problématique industrielle et de la commercialisation du système. Le deuxième objectif est plus orienté « recherche » et nécessite de développer des approches de modélisation & expérimentation plus risquées. Il concerne le contrôle du peigne optique généré par le COEO et l’optimisation du battement pour une génération très haute fréquence.
Cette étude sera menée sur une durée de deux ans.
Key words: microwave optics, mode locked lasers, microwave oscillator, fiber optics, phase noise, optical frequency comb, millimeter waves
LAAS is today involved in investigating a system for the microwave generation with optics based on a mode-locked laser. More precisely, it is a COEO (Coupled Opto-Electronic Oscillator), in which a microwave oscillator is coupled to an optical oscillator, both oscillators sharing the same resonator (optical). The goal of this post-doctoral position is twofold: firstly to improve the performance of an already realized 10 GHz COEO and to transfer the device towards an industry partner (OSAT) and, secondly, to increase the output frequency of the COEO above 100 GHz using the system nonlinearities and, probably, a fundamental frequency of 30 GHz in place of 10 GHz. In a first step, the investigations will focus on the frequency control of the 10 GHz COEO, together with the improvement of its sensitivity to vibrations (and particularly of the fiber spool). This first step is close to the industry requirements. In a second step, the millimeter wave device will be studied, with a focus on the optical comb and a possible RF output at about 100 GHz.
Because of these two different topics, the proposed post-doctoral position will be a two years contract.
Location: LAAS-CNRS, Toulouse, France
Duration: 24 months
We are seeking a strongly motivated and mature post-doctoral researcher to take in charge DFT Modelling for depicting complex chemistries at metal oxide surfaces and interfaces. Position is in Toulouse, under the supervision of A. Estève. The fellowship, funded by the IDEX – University of Toulouse should start in 2016, at the earliest convenience.
The post-doc researcher will be fully integrated within a highly multi-disciplinary project’s team (chemists, physicists and technologists) working on the development of multifunctional & performance-tailored nanomaterials for energy.
The applicant will have a pivotal role in the project by bringing fundamental aspects of chemical processes at metal-oxide surfaces (mostly ZnO) and their interfaces with metal and organics. The applicant will work in close collaboration with experimentalists located in Toulouse (LCC, CIRIMAT, CEMES) and at the University of Texas at Dallas.
Among aspects which will be of interest, there are: reaction mechanisms, i.e. atomic or molecular (organic, bio, inorganic) interactions with surfaces, solvent issues, cooperative effects, role of defects are to be investigated in close relation with experimental developments.
Required Education and Experience - A recent PhD degree (within last three years) in Materials Science, noticeably Chemistry or related disciplines is required. We seek for a strongly motivated student with strong background in computational materials sciences, particularly in atomic scale modelling; skills in manipulating Density Functional Theory codes (both periodic or cluster packages) is mandatory. The applicant should send a detailed CV, including a list of publications and communications and a motivation letter to email@example.com.
Proposition Ingénieur de Recherche ou Post-doc au LAAS-CNRS équipe NEO
12 mois à partir du 1er janvier 2017
Développement de techniques de microfabrication (MEMS) et mise au point de films minces par PVD à base de métaux et bi-métaliques
Compétences requises :
Le ou la candidat(e) doit être formé(e) en :
- utilisation CATIA ou logiciel équivalent,
- technologie MEMS (photolithographies, PVD, gravure chimique, gravure sèche et technique additive).
- méthodes de caractérisations pour qualifier les différentes étapes d’un procédé (profilométrie, mesures électriques, optiques, analyse chimique…).
Le ou la candidat(e) doit être en mesure de travailler en équipe au sein du laboratoire et aussi en collaboration avec un industriel ce qui implique du « reporting », le suivi du projet, la tenue de réunion, le respect de certaines exigences de confidentialité et de rigueur de planning.
Dans ce travail, il est attendu que le ou la candidat(e) mette au point un nouveau composant, répondant à un cahier de charge d’un industriel et ayant un fonctionnement robuste et reproductible. Pour des raisons de confidentialité, les détails ne sont pas fournis dans cette annonce mais seront communiqués au cours de l’entretien.
Une expérience antérieure dans la réalisation de MEMS (capteurs, actionneurs et autres) est nécessaire. Des compétences complémentaires dans les techniques PVD seraient un plus mais ne sont pas obligatoires.
Contact : Carole Rossi, Directeur de recherche CNRS, firstname.lastname@example.org ou tel. 05 61 33 63 01
LAAS-CNRS – NEO team
Duration: 18 months
Contact : Carole Rossi, Directeur de recherche CNRS, email@example.com ou tel. 05 61 33 63 01
LAAS-CNRS seeks for a self-motivated post-doctoral researcher to take in charge a French-US research project aimed at developing advanced nano-material for energy production applications.
The main goal is to explore how the interface chemistry of nanomaterials affects their thermal properties. This position will involve the synthesis of nanoscale thermite materials (e.g., Al/CuO nanolayers) including potential physico-chemical modifications of their interfaces. The candidate will interact with a larger group effort exploring advanced thin films and nanomaterials for energy production applications, with a particular emphasis on controlling the physical structure and interface chemistry of Al/CuO nanolaminates to develop a better understanding of the fundamental structure-property relationships of such materials. The collaborative environment requires a candidate who has the ability to work as part of a team with scientists coming from different disciplines and to learn topics outside his area of expertise. The position will involve a combination of nano fabrication (RIE, photolithography, PVD), advanced characterization (HR-TEM, XPS, DRX) as well thermal and electrical analysis to characterize accurately the energetic capabilities.
The candidate will be required to work temporary in clean room facilities and to follow safe work procedures, as well as to handle chemical waste properly and keep a clean, well-organized work environment.
Required Education and Experience:
Must be a recent PhD graduate (within the last three years).
The ideal candidate for this position should have a strong background in the following areas: (1) nanomaterial synthesis and manipulation; (2) physico-chemical modificaions of surfaces (e.g., nanocrystals, nanowires, thin films); and (3) nanoscale characterizing nanomaterials and their surfaces. Although general expertise in nanotechnologies, chemical engineering and manipulation will be considered.
Preferred Qualifications Ph.D. in materials science & engineering, physics, mechanical/electrical engineering or related fields.