Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 83 for “"Polaritons"”.
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Nonlinear Processes in Room Temperature Exciton-Polaritons
… hybrid light-matter states known as exciton-polaritons form, leading to enhanced light matter interaction, modified material properties, and novel quantum phenomena. In this thesis, we explore the phenomenology of exciton-polaritons in strained TMD microcavities, 2D perovskites, fluorescent …
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Excitations in superfluids of atoms and polaritons
This thesis is devoted to the study of excitations in atomic and polariton Bose-Einstein condensates (BEC). These two specimens are prime examples for equilibrium and non equilibrium BEC. The corresponding condensate wave function of each system satisfies a particular partial differential equation …
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Phonon-polaritons in bulk and patterned materials
… explores the spectroscopic properties of phonon-polaritons, which are admixtures of coupled electromagnetic and mechanical vibrations in polar crystals. An in-depth theoretical treatment supplemented with simulations of experimental results of a four-wave mixing impulsive stimulated Raman …
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Theory of terahertz intervalence band polaritons and antipolaritons.
… excitations in microcavities leading to THz polaritons and antipolaritons. The approach is based on the dielectric function formalism. The dielectric constant is derived from an optical susceptibility evaluated with Non Equilibrium Many Body Green's Functions (NEGF), which is then adjusted to …
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Spin and lattice properties of optically trapped exciton polaritons
Exciton-polaritons are the fundamental excitations arising from the strong coupling of quantum well excitons and cavity photons in semiconductor microcavities. They are compound bosons for which stimulated scattering and macroscopic occupation of single quantum states can occur at sufficiently high …
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Excitation, Interaction, and Scattering of Localized and Propagating Surface Polaritons
Surface polaritons, i.e., collective oscillations of the surface charges, strongly influence the optical response at the micro- and nanoscale and have to be accounted for in modern nanotechnology. Within this thesis, certain basic phenomena involving surface polaritons are investigated by means of …
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Nano optics With Phonon-Polaritons in Van der Waals Materials
Tesis doctoral con mención internacional
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Using 2D vortex plasmons/phonon polaritons to control electronic selection rules
… polariton vortex modes (for plasmon and phonon polaritons) and a hydrogen atom, and show that these modes can be used to engineer new selection rules in electronic transitions. Moreover, we show that these selection rules are robust to the displacement of the electronic system away from the …
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Effects of interactions on correlation, thermalization, and transport of exciton-polaritons
… in terms of single-particle physics. Exciton-polaritons (hereafter "polaritons") are hybrid quasiparticles in a semiconductor quantum-well microcavity that exhibit both light-matter and matter-matter interactions. Polaritons have the effective mass inherited from the ultralight cavity photon …
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Exciton-polaritons in thermal equilibrium : from Bose-Einstein condensation to exciton-polaritonics
… Bose-Einstein condensates. Microcavity exciton-polaritons, hereafter simply polaritons, are bosonic quasiparticles formed in a resonant semiconductor microcavity by coupling the excitonic polarizabilities in quantum wells to the transverse mode of the confined optical field in the cavity. The …
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Energy transmission through and along thin films mediated by surface phonon-polaritons
Surface phonon-polaritons are hybrid electromagnetic modes that are the result of photons coupling to transverse optical phonons. Recently, these surface modes have received much renewed interest primarily due to the fact that micro-fabrication techniques can now routinely create structures at the …
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Coherently-driven exciton polaritons and directional cQED effects in the quantum dot-micropillar system
Cavity quantum electrodynamic (cQED) systems have attracted extensive research interest in the past decades as the main driving force of quantum optics. First experimental demonstrations focused on the enhancement of spontaneous emission and optical nonlinearities related to a single quantum …
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Surface phonon polaritons coupled to the far-field by a grating at high temperature
This thesis explores surface phonon polaritons (SPhP) in quartz coupled to the far field by gratings, and the temperature dependence of SPhP coupled to the far field. The subject of coupling SPhP to the far-field has been studied in the past, but not at high temperature. Devices proposed to control …
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Polarization Conversion Mediated Surface Plasmon Polaritons in Extraordinary Optical Transmission through a Nanohole Arrays
… has focused on the role of surface plasmon polaritons (SPPs) in EOT. While the energy and momentum conditions have become clear, no consensus has been reached on the role of incident light polarization. This study presents a simple model that captures Bloch-SPP excitation, including the role …
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Frequency-resolved ultrafast dynamics of phonon polariton wavepackets in the ferroelectric crystals LiNbO₃ and LiTaO₃
… to study the selective excitation of phonon polaritons. These quasi-particles arise from the coupling of electro-magnetic waves and transverse optical lattice modes, the so-called phonons. The phonon polaritons were investigated in the optically non-linear, ferroelectric crystals LiNbO₃ and …
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Optical control of polariton condensation and dipolaritons in coupled quantum wells
Polaritons are lightweight bosonic quasiparticles that result from the strong coupling of light with an exciton transition inside a microcavity. A sufficiently dense cloud of polaritons condenses into a polariton condensate, a state of matter showing macroscopic coherence and superfluid properties, …
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Correlated exciton dynamics in semiconductor nanostructures
… and forming new quasi-particles called exciton-polaritons. Theoretical work has suggested exciton-polariton Coulomb correlation strengths can be reduced compared to that of excitons. Using two-dimensional Fourier-transform optical spectroscopy, control of Coulomb correlations was demonstrated by …
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Polaritonics : an intermediate regime between electronics and photonics
… and lattice vibrational waves known as phonon-polaritons, rather than currents or photons. Impulsive stimulated Raman scattering (ISRS) is employed for phonon-polariton generation, whereby lattice vibrations are driven by optical femtosecond laser pulses directed into ferroelectric LiNbO3 or …
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I. Resonant Two-Photon Reabsorption by Exciton-Polaritons in Cuprous Chloride Films. Ii. Heat Pulse Propagation Across Metal/sapphire Interfaces. Iii. Phonon Focusing in Piezoelectric Crystals
The work described in this thesis involves the study of optical and thermal properties of semiconductors and consists of three separate topics.
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