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Visar resultat 16 - 20 av 848 avhandlingar som matchar ovanstående sökkriterier.
16. Integrated Nonlinear Optics in Silicon Nitride Waveguides
Sammanfattning : Integrated optics platforms offer the possibility to implement compact photonic devices for nonlinear optics applications. Modern nanofabrication facilities allow thefabrication of sub-micron-sized waveguide geometries that confine light to reach very high optical intensities. LÄS MER
17. Twist-Symmetric Periodic Structures : Properties and Applications
Sammanfattning : In this thesis, periodic structures with higher symmetries symmetries are discussed. The main focus of the thesis is on twist symmetries. Importantly, the attractive properties of twist symmetries for the control of electromagnetic wave propagation are demonstrated. LÄS MER
18. Theoretical Atomic Spectroscopy of Earthbound and Stellar Plasma
Sammanfattning : Motivated by spectroscopic analysis of astrophysical and laboratory plasma, this thesis concerns the fundamental structure and spectral properties of atoms and their ions. The multiconfiguration Dirac-Hartree-Fock (MCDHF) method is used to predict the emission or absorption of radiation, by atomic systems in general, and of heavy and highly charged ions in particular. LÄS MER
19. Multimodal Imaging of Anisotropic Hierarchical Materials
Sammanfattning : The thesis is focused on studying the nanostructure of natural and synthetic hierarchical materials with biological applications, using X-ray scattering imaging and birefringence microscopy. The term "hierarchical materials" is used for structures composed of sub-units organised in different length scales that create the building blocks for the next level. LÄS MER
20. Nonlinearity mitigation in phase-sensitively amplified optical transmission links
Sammanfattning : The fundamental limitations in fiber-optic communication are caused by optical amplifier noise and the nonlinear response of the optical fibers. The quantum-limited noise figure of erbium-doped fiber amplifier (EDFA) or any phase-insensitive amplifier is 3 dB. LÄS MER