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 87 for “"Polariton"”.
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Phonon polariton interaction with patterned materials
… propagation and detection of THz phonon polaritons are studied through both femtosecond pump-probe techniques, and Finite Difference Time Domain (FDTD) simulations in this thesis. The theory surrounding the driving, propagation and detection of these modes is treated in a consistent …
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Engineering J-aggregate cavity exciton-polariton devices
… light-matter quasi-particles known as exciton-polaritons, even at room temperature. In this thesis, I discuss my research on the properties of J-aggregate thin films and on advancing the device and materials engineering of strongly-coupled devices based on J-aggregate thin films to the level of …
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Modeling phonon-polariton generation and control in ferroelectric crystals
… using Finite Element Method (FEM), of phonon-polariton generation and coherent control in ferroelectric crystals LiNbO₃ and LiTaO₃ through nonlinear electro-optic interactions with ultrashort laser pulses. This direct space-time monitoring platform is used to investigate the nature of the …
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Two-photon absorption and nonlinear polariton effects in organic crystals
… (TPA), the relationship between TPE and SHG, and polariton effects. The transition studied is of special interest because it is both one- and two-photon allowed in the dipole approximation. Consequently, polariton states and SHG play a role in the two-photon process. In the polariton model, both …
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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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Photostabilization of J-aggregate cyanine dyes for exciton-polariton based devices
… allowed for the creation of room temperature polariton condensates, superfluids, and other exotic phenomena. Using J-aggregates, the aggregated form of cyanine organic dyes, we have previously fabricated light-emitting devices that demonstrated the first ever electrically pumped polariton …
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Design of Phonon Polariton Propagation in Thin Layers of Highly Anisotropic Materials
… últimas décadas es la conversión de la luz en polaritones superficiales (luz acoplada a excitaciones dipolares en la materia). Estas ondas electromagnéticas superficiales exhiben un fuerte confinamiento espacial debido a su decaimiento evanescente, así como longitudes de onda que pueden ser …
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Electrically pumped polariton emission in a J-aggregate organic light emitting device
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.
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Energy transfer between surface plasmon polariton modes with hybrid photorefractive liquid crystal cells
… photorefractive control of Surface Plasmon Polaritons (SPP). The photorefractive effects are generated through optically controlling the conductivity of a ~100nm photoconducting poly-N-vinyl-carboxyl (PVK) layer. Therefore, when a potential is applied across the cell, the liquid crystal …
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Surface plasmon polariton mediated energy transfer from external antennas into organic photovoltaic cells
… into the photovoltaic cell via surface plasmon polariton modes in an interfacial thin silver contact. By decoupling the optical and electrical functions of the cell, this new architecture has the potential to circumvent the tradeoff between light absorption and charge separation efficiency. …
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Passive and Thermo-Optic Characterization of Long-Range Surface Plasmon-Polariton Structures in CYTOP
Long-range surface plasmon-polariton waveguides fabricated of gold, cladded with CYTOP, designed to be 5μm wide and 35nm thick, were modelled and fabricated by other researchers and tested by the author. In passive measurements, cutback curves were drawn and S-bends, Y-junctions, Mach-Zehnder …
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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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Exciton-polaritons in thermal equilibrium : from Bose-Einstein condensation to exciton-polaritonics
… collective system, namely, microcavity exciton-polariton 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 …
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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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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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Development of phonon-polarization THz spectroscopy, and the investigation of relaxor ferroelectrics
This thesis develops phonon-polariton based THz spectroscopy and uses this technique to make the first THz frequency dielectric measurements of a relaxor ferroelectric crystal, in particular KTao0.982Nb0.018O3 (KTN 1.8). THz spectroscopy has emerged as an important probe for a wide variety of …
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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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Control of Nonlinear Properties of van der Waals Materials
… the formation of hybrid quasi-particles exciton-polaritons. This thesis<br />focuses on exploring and enhancing nonlinearity of van der Waals materials through strongly coupling to microcavities. By taking advantage of the stacking order of TMDs, we show intense second-harmonic generation from …
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Linear and nonlinear optical processes in GaAs semiconductor microcavities
In this thesis, polariton dynamics in GaAs semiconductor microcavities are investigated. Insertion of layers of active material within a Fabry-Perot resonator leads to strong coupling between excitons and photons, giving rise to new eigenmodes called excitonpolaritons.<br/><br/>Bose-Einstein …
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