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 17 of 17 for “"phonon-polaritons"”.
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Phonon-polaritons in bulk and patterned materials
… thesis 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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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
… carrying 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 …
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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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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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Frequency-resolved ultrafast dynamics of phonon polariton wavepackets in the ferroelectric crystals LiNbO₃ and LiTaO₃
… enables 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 …
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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 …
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Phonon polariton interaction with patterned materials
The generation, 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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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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Phonon Behaviour at Advanced Material Interfaces using Electron Energy Loss Spectroscopy
… (STEM) enable the study of lattice vibrations (phonons) with nanoscale spatial resolution using electron energy loss spectroscopy (EELS). Probing phonons at this spatial resolution provides access to vibrational properties associated with structural features in which the crystal symmetry is …
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Probing extraordinary nanoscale energy transfer using bimaterial microcantilevers
… free path of energy carriers such as photons, phonons and electrons. Due to the small dimensions, probing energy transfer at the nanoscale is extremely challenging. By developing new experimental techniques based on the bi-material microcantilevers used in Atomic Force Microscopes (AFM), this …
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A fundamental study of epitaxial graphene on silicon carbide on silicon for mid-infrared nanophotonics
… the tunable nature of graphene surface plasmon polaritons (SPPs) with low loss surface phonon polaritons (SPhPs) supported in SiC offers great promise. The epitaxial graphene (EG) platform technology on cubic silicon carbide on silicon wafer has substantially advanced over the last decade and …
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THz polaritonics : control, confinement, and strong light-matter interactions
… laser pulses are used to generate and detect THz phonon-polariton wavepackets with full spatiotemporal resolution while they are confined to a thin slab of lithium niobate (LN) or lithium tantalate (LT) that is roughly 30-100 pm thick. Polaritonics is an attractive platform for wave-based …
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A Theoretical Study on the Effect of Curvature on Near-field Radiative Transfer
… polar dielectric materials which support surface phonon polaritons (SPPs). When two such bodies are brought in close proximity to each other, the enhanced near-field radiation due to tunneling of SPPs can exceed the classical black body limit by several orders of magnitude. This enhanced radiation …
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Developments in THz Polaritonics: Towards Integrated Nonlinear THz Spectroscopy
… Previous experiments coupling the THz phonon-polaritons in a LN waveguide to the quasi-antiferromagnetic magnon mode in an adjacent slab of ErFeO₃ took advantage of the fact that both materials have similar refractive indices. Furthermore, the ErFeO₃ layer complicates THz imaging …
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Engineering the couplings to the continuum : controlling the fundamental properties of radiation and enabling forbidden light-matter
… of electrons to the electromagnetic fields of polaritons such as plasmon and phonon-polaritons. We consider the potential for 2D materials such as graphene, thin films of SiC, and hBN to enable atomic and molecular transitions that have, to this date been either very difficult to observe, or …
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Electronic, optical, and lattice properties of superlattices and heterostructures
Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-18T14:35:39Z No. of bitstreams: 1 1989_chu.pdf: 8024583 bytes, checksum: ff256b7b8b05a483d9d7936f2cf1f346 (MD5)