Dissertationen zum Thema „Effet stark quantique“
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Le, Thomas Nicolas. „Diode laser accordable en longueur d'onde par effet Stark quantique confiné“. Grenoble INPG, 2002. http://www.theses.fr/2002INPG0116.
Der volle Inhalt der QuelleHaas, Helge. „Effet Stark quantique dans les puits de CdTe/CdZnTe et développement d'un dispositif photoréfractif“. Université Joseph Fourier (Grenoble ; 1971-2015), 1995. http://www.theses.fr/1995GRE10146.
Der volle Inhalt der QuelleDonon, Jeremy. „Caractérisation de paires d’ions par spectroscopies IR, UV et rayons X, interprétées par calculs de chimie quantique“. Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS106.
Der volle Inhalt der QuelleIon pairs are ubiquitous in nature, from sea water, aerosols, to living organisms. They influence the properties of concentrated ion solutions, and thus play a crucial role in various chemical reactions and biological processes. However, the characterization of ion pairs faces some difficulties: on one hand, several types of pairs coexist, and on the other hand, they are transient species in solution. In this context, this work presents several studies carried out according to three main research studies, backed by an original approach in the gas phase, and then in solution. Firstly, the effects of the electric field produced by the ion pair on the UV spectroscopy of a chromophore in gas phase (Stark effects) are studied. The ion groups can produce an electric field high enough to induce significant electronic Stark effects on a nearby UV chromophore. This study is conducted on model systems (C₆H₅-(CH₂)n-COO⁻,M⁺) with M = Li, Na, K, Rb, Cs and n = 1-3, allowing to vary the electric field experienced by the UV chromophore. These different systems are studied in the gas phase by UV spectroscopy combined with quantum chemistry calculations, as well as by conformation selective IR spectroscopy. Based on the analysis of the electronic Stark effects, precise conformational assignments can be proposed for electronic transitions separated by a few cm-1, without resorting to IR spectroscopy, or frequency calculations. The next study is focused mainly on understanding the environmental effects on ion pairs by microsolvation experiments in gas phase. The pair of sodium acetate ions [CH₃-COO⁻,Na⁺] is studied for the first time in a trimer complex with p-xylene by IR spectroscopy. Microhydration experiments are then carried out on charged ion pairs ([CH₃-COO⁻,M²⁺]; M = Ca, Ba), highlighting two different behaviours depending on the nature of the cation. The final research is to detect and identify the structures formed by the ions in electrolytic solutions by IR and RX spectroscopy. The first experiment is carried out on electrolytic solutions ([CH₃-COO⁻,M⁺]; M = Li, Na and K) by TF-IR spectroscopy by varying the ion concentration. A theoretical study is then carried out in order to propose a theoretical spectrum for each type of pair, and to confront them with experimental spectra in solution. The approach is based on the calculation of the IR signature of pairs ([CH₃-COO⁻,M⁺]; M = Li, Na, K, Rb and Cs) and free anion in solution, where the first solvation layer were described at the quantum level, followed by a solvent continuum. For each type of pair, spectroscopic families, consistent with the experimental data, are identified. This original approach paves way to the identification of supramolecular structures in electrolytic solutions. Finally, the first FZRET experiment in liquid micro-jet is carried out on a potassium acetate solution, providing access to a measurement of the distance distribution between cations and paired anions.In these studies, different methods are used ranging from experiment to theory, from the gas phase to solution. This work illustrates the need to combine several methods in order to obtain additional data and allow a better characterization of the supramolecular organisation of ions and their environment
Billaud, Baptiste. „Sur quelques propriétés des boîtes quantiques sphériques semiconductrices“. Paris 6, 2009. http://www.theses.fr/2009PA066615.
Der volle Inhalt der QuelleTeissier, Jean. „Nouvelles fonctionnalités dans les lasers à cascade quantique : contrôle de l'indice optique complexe intracavité“. Paris 7, 2010. http://www.theses.fr/2010PA077262.
Der volle Inhalt der QuelleThe control of the complex refractive index of the optical mode in a quantum cascade laser (QCL) is a major issue as in spectroscopy as in telecommunications. Indeed, this control would allow a precise tuning of the laser wavelength due to the generation of lateral sidebands for the real part and directly for the imaginary part. In a first time we developed a device allowing the intracavity control of the laser losses. The idea is to couple the laser cavity with another one containing a control area. This control area is composed by a stack of two asymmetric coupled wells who's absorption energy is controlled by the interssuband Stark effect, by appling a bias on this control area independently from the laser bias. This allows an amplitude modulation that can avoid the spectral linewidth enhancement due to thermal effects, with a consumed power near the milliwatt. We also shown the Kramers-Koenig relations inside a QCL, and his application to high frequencies. This word is a collaboration between MPQ/LPN/IEF and is financed by ANR MetalGuide
Pellarin, Michel. „Etude des états de Rydberg de l'argon et du francium par spectroscopie colinéaire : analyse des résultats par la théorie du défaut quantique à une ou plusieurs voies“. Lyon 1, 1989. http://www.theses.fr/1989LYO10011.
Der volle Inhalt der QuelleJankovic, Aleksandar. „Etats électroniques des boîtes quantiques de semiconducteur : rôle de l'environnement et couplage dépendant du spin“. Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00111990.
Der volle Inhalt der QuelleDans une premièm partie, nous étudions le rôle joué par l'environnement électrostatique sur la perte de cohérence dans les boîtes. Nous montrons que les fluctuations électrostatiques sont essentiellement de deux types, engendrant soit un décalage en énergie de la transition sans induire de déphasage, soit un élargissement homogène du type rétrécissement par le mouvement.
Dans une deuxième partie, nous nous intéressons à l'effet de l'interaction d'échange longue portée sur la structure fine de l'exciton confiné dans la boîte. En particulier, nous montrons la possibilité d'annuler le splitting d'échange résultant de l'anisotropie de forme de la boîte en appliquant un champ électrique le long de son grand axe. Nous montrons enfin qu'une anisotropie de polarisation apparaît à cause de la nature même de l'interaction d'échange.
Vasanelli, Angela. „Transitions optiques interbandes et intrabandes dans les boites quantiques simples et couplées verticalement“. Phd thesis, Université Pierre et Marie Curie - Paris VI, 2002. http://tel.archives-ouvertes.fr/tel-00003115.
Der volle Inhalt der QuelleOllagnier, Antoine. „Microscopie de Photoïonisation : une étude classique, semi-classique et quantique“. Phd thesis, Université Claude Bernard - Lyon I, 2007. http://tel.archives-ouvertes.fr/tel-00250373.
Der volle Inhalt der QuelleSaab, Mohamad Yehia. „Photochimie organique guidée par pulses laser : Applications : Benzopyrane et Pyrazine“. Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20014/document.
Der volle Inhalt der QuelleThe ring-opening photoisomerization of benzopyran, which occurs via a photochemical route involving a conical intersection,has been studied with quantum dynamics calculations using the multi-configuration time-dependent Hartree method (MCTDH). We introduce a mechanistic strategy to control the conversion of benzopyran to merocyanine with laser pulses. We use asix-dimensional model developed in a previous work for the potential energy surfaces (PES) based on an extension of thevibronic-coupling Hamiltonian model (diabatization method by ansatz), which depends on the most active degrees of freedom. The main objective of these quantum dynamics simulations is to provide a set of strategies that could help experimentalists tocontrol the photoreactivity vs. photostability ratio (selectivity). In this work we present:(i) a pump-dump technique used tocontrol the photostability, (ii) a two-step strategy to enhance the reactivity of the system: first, a pure vibrational excitation inthe electronic ground state that prepares the system and, second, an ultraviolet excitation that brings the system to the firstadiabatic electronic state; (iii) finally the effect of a non-resonant pulse (Stark effect) on the dynamics
Dussaigne, Amélie. „Diodes électroluminescentes blanches monolithiques“. Phd thesis, Université de Nice Sophia-Antipolis, 2005. http://tel.archives-ouvertes.fr/tel-00332387.
Der volle Inhalt der QuelleBaaboura, Jassem. „Effets de confinement quantique dans les matériaux de faible dimension dévoilés par des spectroscopies électroniques corrélées dans le temps“. Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP025.
Der volle Inhalt der QuelleA profound understanding of interactions within luminescent materials under excitation is imperative for advancing optoelectronic devices. Materials with small dimensions exhibit unique optoelectronic properties resulting from quantum effects and spatial confinement.Our approach to analyzing the optoelectronic properties of nanomaterials is marked by a versatile methodology, employing various techniques integrated into the scanning transmission electron microscope (STEM). Utilizing an accelerated electron source at 60 keV, our study successfully overcame diffraction limitations. The STEM microscope, with nanometric resolution capabilities in measuring energy absorption through transmitted electron energy loss spectroscopy (EELS), formed the central aspect of our exploration. Enhanced by an integrated spectroscopic system into the microscope, we performed an in-depth analysis of the luminescence spectrum (cathodoluminescence) of nanostructures.The integration of these techniques facilitates the exploration of optoelectronic effects induced by excitons in low-dimensional materials, particularly in monolayer TMD-based heterostructures (WS2 et MoSe2) that were carefully prepared in a cleanroom. Luminescence mappings revealed correlations between the emission intensity of exciton XA and the trion, depending on the spatial displacements of the probe across the sample surface. These observations enabled deductions about the dependence of trion or exciton generation on the deformations of the layers within the heterostructure.Excitation by an electron source induces multiple electronic transitions, presenting a challenge compared to optical excitation. To tackle this challenge, the STEM team at LPS developed an experimental technique, the cathodoluminescence excitation spectroscopy (CLE), to identify the electron responsible for the emission of each photon. This identification, coupled with the magnetic spectrometer providing information on the energy absorbed by the sample, facilitates identifying the type of excitation leading to photon emission. The identification of the electron responsible for photon emission was achieved through temporal coincidence, utilizing a photomultiplier and a temporally resolved electron detector, Timepix3.A thorough investigation of the Timepix3 detector during this thesis unveiled the underlying mechanisms, spanning from the initial impact of the electron on the detector surface to its subsequent detection within the readout layer. This study, incorporating various experimental approaches, significantly contributed to the precise characterization of the detector, ultimately optimizing its temporal resolution.The temporal coincidence technique was applied to other low-dimensional materials, such as AlN nanowires with GaN/AlN quantum wells. This approach provided insights into the lifetime of excitations, uncovering a close dependence on the screening of the electric field within these nanowires. Simulations and experimental results demonstrated notable variations based on the current and spatial excitation position within the nanowire. While these dependencies are distinct, they are closely interlinked, influencing the migration of charges from barriers to wells and thus exerting a significant impact on the lifetime and emission energy of excitons.Finally, an energy-dependent study of electrons coinciding with photons unveiled the emission efficiency for each energy absorption, highlighting specific de-excitation processes leading to exciton generation, resulting in photon emission.These results not only enhance our comprehension of low-dimensional materials but also forge new pathways for the development of optoelectronic devices, particularly LEDs
Sala, Matthieu. „Quantum dynamics and laser control for photochemistry“. Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS039.
Der volle Inhalt der QuelleThe central subject of this thesis is the theoretical description of ultrafast dynamical processes in molecular systems of chemical interest and of their control by laser pulses. We first use electronic structure calculations to study the photochemistry of aniline. A umber of previously unknown features of the potential energy surfaces of the low-lying elec-tronic states are reported, and analyzed in relation with the experimental results available. We use quantum dynamics simulations, based on a model Hamiltonian including the four lowest excited electronic states and sixteen vibrational modes, to investigate the photochem-istry of pyrazine. We show that the dark Au(nπ∗) state plays an important role in the ultrafast dynamics of the molecule after photoexcitation. The laser control of the excited state dynamics of pyrazine is studied using a simplified two-state four-mode model Hamiltonian. We propose a control mechanism to enhance the lifetime of the bright B2u(ππ∗) state using the Stark effect induced by a strong non-resonant laser pulse. We finally focus on the laser control of the tunneling dynamics of the NHD2 molecule, using accurate full-dimensional potential energy and dipole moment surfaces. We use simple effective Hamiltonians to explore the effect of the laser parameters on the dynamics and design suitable laser fields to achieve the control. These laser fields are then used in MCTDH quantum dynamics simulations. Both enhancement and suppression of tunneling are achieved in our model
Miffre, Alain. „Interférométrie atomique avec l'atome de lithium : mesure de précision de la polarisabilité électrique“. Phd thesis, Université Paul Sabatier - Toulouse III, 2005. http://tel.archives-ouvertes.fr/tel-00010306.
Der volle Inhalt der QuelleBardoux, Richard. „Spectroscopie de boîtes quantiques individuelles GaN/AlN en phase hexagonale“. Phd thesis, Montpellier 2, 2007. http://www.theses.fr/2007MON20173.
Der volle Inhalt der QuelleWe study the optical properties of GaN/AlN quantum dots (QDs) grown by molecular beam epitaxy on Si(111) substrates. Time-resolved spectroscopy of the collective emission from QD planes leads us to an appropriate determination of the QD ground state and of the on-axis internal electric field. We observe and model a nonconventional carrier recombination process. These preliminary results allow us to select the QDs that are ideal for individual studies by micro-photoluminescence. Our measurements on single QDs reveal spectral diffusion effects that we study in detail. By analyzing linear polarization of the emission lines of individual quantum dots, we observe properties related to the excitonic fine structure, very different from those of previously studied QDs, which we explain via a modeling accounting for exchange and anisotropy effects
Bardoux, Richard. „Spectroscopie de boîtes quantiques individuelles GaN/AlN en phase hexagonale“. Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2007. http://tel.archives-ouvertes.fr/tel-00201492.
Der volle Inhalt der QuelleBahlak, Samia. „Contribution à l'étude d'un modulateur acousto-optique à puits quantiques“. Valenciennes, 1997. https://ged.uphf.fr/nuxeo/site/esupversions/a93e0d34-1079-4e51-b081-345993233dd1.
Der volle Inhalt der QuelleAshkarin, Ivan. „Few-body Förster resonances in Rydberg atoms for the implementation of quantum computing“. Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASP199.
Der volle Inhalt der QuelleApplication of few-body Förster resonances for implementation of multiqubit quantum gate circuits has been investigated. New types of three-atom Borromean transitions based on the relay atom have been proposed and numerically studied. In particular, a Stark-controlled non-isolated three-atom Förster resonance between high-lying n = 80, 81, 82 S − P states of Rb atoms isolated in individual optical traps has been modeled. Isolated three-atom Förster resonance has also been demonstrated for n = 70, 71 states of Rb atoms. The resonances were investigated in a fixed spatial configuration, allowing us to demonstrate the coherent population and phase dynamics of the collective states involved. Three-qubit Toffoli gates schemes have been developed and numerically modeled based on the demonstrated resonances. Also, a generalized doubly controlled phase CCPHASE gate scheme has been developed based on the radiofrequency-induced three-body Förster resonance. Additionally, a similar quantum gate scheme has been proposed based on two-atom RF-induced Förster resonance with controlled displacement. The fast performance and high fidelity of the proposed schemes, as well as their potential robustness to errors, allow us to expect a successful experimental implementation in the near future
Simon, Julia. „Étude des propriétés optiques de nanostructures quantiques à base de nitrures d'éléments III“. Université Joseph Fourier (Grenoble ; 1971-2015), 2001. http://www.theses.fr/2001GRE10115.
Der volle Inhalt der QuelleOrtiz, Valentin. „Etude de dispositifs optoélectroniques à base d'hétérostructures piézoélectriques“. Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10132.
Der volle Inhalt der QuelleRol, Fabian. „Etude optique de boîtes quantiques uniques non polaires de GaN/AlN“. Phd thesis, Université Joseph Fourier (Grenoble), 2007. http://tel.archives-ouvertes.fr/tel-00173308.
Der volle Inhalt der QuelleLa réalisation d'un montage de microPL optimisé pour l'UV nous a permis d'isoler les premiers spectres de BQs uniques de GaN plan a. Des effets de charges locales responsables de l'élargissement des raies de PL (diffusion spectrale) ont pu être mises en évidence et partiellement contrôlés par l'application d'un champ électrique vertical.
La dépendance en température des raies de BQs uniques nous a permis d'étudier le couplage de l'exciton confiné avec les phonons acoustiques. La modélisation de ce mécanisme ainsi que les valeurs des temps de déclin indiquent que la localisation latérale de l'exciton est plus forte que celle imposée par la boîte.
Rakotonanahary, Georges. „Spectroscopie des transitions excitoniques dans des puits quantiques GaN/AlGaN“. Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00662445.
Der volle Inhalt der QuelleVasanelli, Angela. „Transitions optiques interbandes et intrabandes dans les boîtes quantiques simples et couplées verticalement“. Paris 6, 2002. http://www.theses.fr/2002PA066800.
Der volle Inhalt der QuelleAfter an introduction on the methods used for electronic states calculation, we study electron and hole bound states in a single dot. We initially evaluate the oscillator strength and polarization selection rules for intraband transitions. We show that in a single dot the absorption is very anisotropic, depending on the polarization direction of the incident light. We also develop a model for interpreting some recent STM measurements, which are able to "image" single dot wavefunctions. Then we study vertically stacked quantum dot systems. We examine the coupling between the dots of a stack as a function of the barrier the thickness. Systems of strongly coupled dots are particularly interesting : we show that the optical anisotropy, typical of single dots, considerably diminishes in this kind of systems. Strongly couple dots are also interesting when electric field effects are studied. We show that they are as tunable as quantum wells, of the same dimensions, when an uniform electric field is applied in the growth direction. In addition to this enhanced Stark tunability, stacked dots present the advantage over quantum wells that no continuum absoprtion exists. The last part of this work is devoted to a detailed numerical study of continuum, wetting layer (2D) and barrier (3D), states. We show that the continuum states have an important role for interband transitions. We show in particular that crossed transitions, which involve bound and continuum states, lead to the appearance of a continuous background in the interband absorption spectrum in the energy range between the bound-to-bound transitions and the wetting layer absorption edge. The existence of this background, experimentally proved, shows that the "artificial atom" model is too simple to describe the features of quantum dot interban spectrum
Harb, Mahdi. „Microscopie de fonction d’onde électronique“. Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10150/document.
Der volle Inhalt der QuelleThis work of thesis aims to visualize, on a position sensitive detector, the spatial oscillations of slow electrons (~meV) emitted by a threshold photoionization in the presence of an external electric field. The interference figure obtained represents the square magnitude of electronic wavefunction. This fundamental work allows us to have access to the electronic dynamics and thus to highlight several quantum mechanisms that occur at the atomic scale (field Coulomb, electron/electron interaction..). Despite the presence an electronic core in Li atom, we have succeeded, experimentally and for the first time, to visualize the wave function associated with the quasi-discrete Stark states coupled to the ionization continuum. Besides, using simulations of wave packet propagation, based on the "Split-operator” method, we have conducted a comprehensive study of the H, Li and Cs atoms while revealing the significant effects of the Stark resonances. A very good agreement, on and off resonances, was obtained between simulated and experimental results. In addition, we have developed a generalized analytical model to understand deeply the function of VMI spectrometer. This model is based on the paraxial approximation; it is based on matrix optics calculation by making an analogy between the electronic trajectory and the light beam. An excellent agreement was obtained between the model predictions and the experimental results
Sainte-Rose, Frédéric. „Modulateur acousto-optique à puits quantiques : étude théorique et expérimentale“. Valenciennes, 2001. https://ged.uphf.fr/nuxeo/site/esupversions/f54ffb6f-490e-4edc-9dc7-ec92d0f5ce84.
Der volle Inhalt der QuelleWe present a new asymmetric Fabry-Perot acousto-opto-electronic multi-quantum-well modulator structure for optical telecommunications. We elaborated a complete numerical method to analyse the optical reflection coefficient variations produced by various surface acoustic wave powers. We took into account excitonic effect, quantum confined stark effect, strain effect, and the electrical field induced by this SAW. We determined the strain field, as well as the electrical field accompanying the wave using Laguerre polynomial method. Electronic states were calculated by the finite elements method taking account electronic parameter modifications induced by deformations. The complex refractive index was determined from wave functions and energy levels. The overall optical reflection coefficient of the multi-layered modulator is given. The experimental study by photoreflectance shows the validity of our model and the feasibility of such structures
Calvas, Bernard. „Contribution à l'optimisation de structures laser à puits quantiques contraints sur la maille d'InP“. Toulouse, INSA, 1994. http://www.theses.fr/1994ISAT0011.
Der volle Inhalt der QuelleIssanchou, Olivier. „Contribution à l'optimisation de structures lasers à puits quantiques contraints sur InP, à base des systèmes GaInAsP/GaInAsP/InP et GaInAs/GaInAlAs/InP. Applications aux télécommunications optiques“. Toulouse 3, 1996. http://www.theses.fr/1996TOU30187.
Der volle Inhalt der QuelleJulier, Michel. „Etudes optiques de GaN et d'InGaN“. Montpellier 2, 1999. http://www.theses.fr/1999MON20099.
Der volle Inhalt der QuelleBouché, Christian. „Etude par électroréflexion d'alliages iii-v à base d'antimoine et des propriétés électrooptiques de super-réseaux GaAs/GaAlAs“. Montpellier 2, 1989. http://www.theses.fr/1989MON20212.
Der volle Inhalt der QuelleRouifed, Mohamed Saïd. „Modulateurs à base de puits quantiques Ge/SiGe pour la photonique sur silicium“. Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112178/document.
Der volle Inhalt der QuelleSilicon photonics has generated a great interest for several years, for applications from long-haul optical telecommunication to intra-chip interconnects. The ultimate integration of optics and electronics on the same chip would allow an increase of the integrated circuit performances at low cost. In this context, the work done during my Ph.D is focused on the study of optical modulation around the direct bandgap of Ge/SiGe quantum well structures, at room temperature, by Quantum Confined Stark effect (QCSE). Electrical and optical simulations have been used to design a modulator operating at 1.3μm. Such device has been fabricated and characterized, demonstrating an extinction ratio up to 6 dB using a 50 µm-long structure. The second objective of my work was to design and demonstrate a modulator integrated on SOI waveguide. The demonstration of an efficient QCSE in Ge/SiGe quantum wells grown on the top of a 360nm homogeneous virtual substrate has paved the way for such integration. Simulations were conducted to demonstrate the feasibility of an evanescent vertical coupling between an SOI optical waveguide and a Ge/SiGe active region and to evaluate the performance of this device. A technological process has then been proposed to fabricate the devices. All steps have been optimized for the fabrication of the modulator integrated with the waveguides. Mainly six electronic beam lithography and four etching steps were used. Preliminary experimental results obtained with such component are presented. This work paves the way to the demonstration of complex photonic integrated circuits, including modulators, photodetectors and passive structures on the same chip
Iehl, Jean-Louis. „Conception et test d'architectures et de composants tout optiques“. Toulouse, INSA, 1994. http://www.theses.fr/1994ISAT0012.
Der volle Inhalt der QuelleVakarin, Vladyslav. „Composants optoélectroniques à base d'alliages SiGe riches en Ge pour le proche et moyen infrarouge“. Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS473/document.
Der volle Inhalt der QuelleToday optical interconnects have overpassed wires on long, mid and short distances on the telecommunication field. Silicon photonics have known such a development that even inter and intra chip communications progressively become optical. However, the multiplication of data access terminals and the constant increase of data consumption force new components with even lower power consumption to appear. In this context, low power consumption components based on Ge/SiGe quantum wells have been developed. Until now, the use of Ge/SiGe quantum wells has been only limited to electroabsorption modulators. The first part of my thesis was dedicated to the study of a new kind of active region based on coupled Ge/SiGe quantum wells. This work led to the demonstration of giant electrorefractive effect in these structures. The active region based on coupled quantum wells gives a refractive index variation of 2.3×10-3 under a bias of only 1.5 V. The use of this effect for the development of integrated optical modulators needed the development of main building blocks to obtain interferometric structures. Compact bends and Mach Zehnder interferometers have been designed, fabricated and successfully characterized. The sensitivity to the polarization of these structures was evaluated with numerical simulations and polarization insensitive structures were designed. Then, an integrated electrorefractive modulator has been designed and fabricated which needed the development of a new technological process. The first charaterization results are presented. The perspectives of this work are the realization of an efficient modulator with switching voltage lower than 2V. The field of application of photonic integrated circuits is not only limited to the telecommunications. The approach based on integrated optics is also very promising for the identification and analysis of surrounding chemical species. Mid infrared spectral region is particularly suitable for this purpose as it contains specific absorption fingerprints of different chemical species. The use of photonic integrated circuits on silicon substrate allows to develop performant, compact and low cost spectroscopic systems. The second part of my thesis was focused on the development of wideband photonic platform based on Ge-rich Si1-xGex waveguides. Wideband waveguides between 5.5 and 8.5 µm were experimentally demonstrated which made possible the developpement of more complex structures such as MMIs or ultra-wideband Mach Zehnder interferometers. The same device has a theoretical bandwidth of 3.5 µm in TE polarization and of one octave in TM polarization. The operation was experimentally demonstrated between 5.5 and 8.6 µm and is only limited by laser spectral range. This work paves the way for future development of ultra-wideband spectroscopic systems on Ge-rich Si1-xGex platform. The last part of this work concerned second harmonic generation in Ge/SiGe quantum wells for mid infrared spectroscopic systems. First test devices have been designed and fabricated
Chaisakul, Papichaya. „Ge/SiGe quantum well devices for light modulation, detection, and emission“. Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00764154.
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