Sökning: "optical lattices"
Visar resultat 11 - 15 av 19 avhandlingar innehållade orden optical lattices.
11. Optical Parametric Devices in Periodically Poled LiTaO3
Sammanfattning : Optical parametric frequency conversion based on quasi phase matching (QPM) in nonlinear optical crystals is a powerful technique for generating coherent radiation in wavelength ranges spanning from the mid-infrared (mid-IR) to the blue, displaying low thermal load and high efficiency.This thesis shows how QPM in one- (1D) or two-dimensional (2D) lattices can be employed to engineer novel devices for parametric downconversion in the IR, af-fording freedom in designing both spectral and angular properties of the parametric output. LÄS MER
12. Cold atoms in a variety of optical lattice potentials
Sammanfattning : In this thesis, both experimental achievements and theoretical preparatory investigationsfor future experiments are introduced. The experiments presentedare performed with the set-up used for laser cooling and trapping of rubidiumatoms, and the theoretical examinations are adopted for intended experimentson Bose-Einstein Condensates. LÄS MER
13. Ultracold rubidium atoms in periodic potentials
Sammanfattning : This thesis includes both experimental and theoretical investigations, presented in a series of eight papers. The experimental part ranges from the construction procedures of an apparatus for Bose-Einstein condensates, to full scale experiments using three different set-ups for ultracold atoms in optical lattices. LÄS MER
14. Comparisons between classical and quantum mechanical nonlinear lattice models
Sammanfattning : In the mid-1920s, the great Albert Einstein proposed that at extremely low temperatures, a gas of bosonic particles will enter a new phase where a large fraction of them occupy the same quantum state. This state would bring many of the peculiar features of quantum mechanics, previously reserved for small samples consisting only of a few atoms or molecules, up to a macroscopic scale. LÄS MER
15. The effect of nano-confinement on hydrogen uptake in metallic superlattices
Sammanfattning : The absorption of hydrogen is exothermic in vanadium whereas it is endothermic in iron and chromium. Investigations of the hydrogen uptake within Fe/V(001) and Cr/V(001) superlattices allow therefore a detailed exploration of finite size effects and the influence of boundaries on hydrogen absorption. LÄS MER
