Sökning: "Atom- och molekylfysik"

Visar resultat 11 - 15 av 846 avhandlingar innehållade orden Atom- och molekylfysik.

  1. 11. Multidimensional Constellation Shaping for Coherent Optical Communication Systems

    Författare :Ali Mirani; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lattice-based constellations; geometric shaping; probabilistic shaping; multidimensional modulation format; Voronoi constellation; constellation shaping; optical communications; coherent receiver;

    Sammanfattning : To overcome the increasing demands for Internet traffic, exploiting the available degrees of freedom in optical communication systems is necessary. In this thesis, we study how constellation shaping can be achieved in various dimensions and how various shaping schemes affect the whole performance in real systems. LÄS MER

  3. 12. Biomimetic surfaces : Preparation, characterization and application

    Författare :Annika Borgh; Bo Liedberg; Fredrik Höök; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Self-assembled monolayers; biomimetic surfaces; phosphates; antifreeze; surface spectroscopy; Molecular physics; Molekylfysik;

    Sammanfattning : I denna avhandling beskrivs tillverkning, karaktärisering och tillämpning av ett antal biomimetiska ytor. Biomimetik är att härma naturen och grundtanken är att titta på hur naturen löst liknande problemställningar. LÄS MER

  4. 13. Studies of Volcanic Plumes with Remote Spectroscopic Sensing Techniques -DOAS and FTIR measurements on volcanoes of the Network for Observation of Volcanic and Atmospheric Change-

    Författare :Santiago Arellano; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; FTIR; Remote Sensing; DOAS; NOVAC; Volcanic gas emissions;

    Sammanfattning : Volcanism is a rich geodynamical process, closely linked to the origin and ongoing evolution of the lithosphere, atmosphere, hydrosphere and biosphere. Humans have benefited from the resources provided by volcanoes but also been threatened by the dangers of volcanic eruptions, which accurate prediction remains elusive. LÄS MER

  5. 14. VCSEL Cavity Engineering for High Speed Modulation and Silicon Photonics Integration

    Författare :Emanuel Haglund; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; high-speed modulation; on-chip laser source; vertical-cavity surface-emitting laser VCSEL ; semiconductor lasers; optical interconnects; large signal modulation; laser dynamics; heterogeneous integration; vertical-cavity silicon-integrated laser VCSIL ; silicon photonics;

    Sammanfattning : The GaAs-based vertical-cavity surface-emitting laser (VCSEL) is the standard light source in today's optical interconnects, due to its energy efficiency, low cost, and high speed already at low drive currents. The latest commercial VCSELs operate at data rates of up to 28 Gb/s, but it is expected that higher speeds will be required in the near future. LÄS MER

  7. 15. Optical Guiding and Feedback Structures in GaN-Based Vertical-Cavity Surface-Emitting Lasers

    Författare :Seyed Ehsan Hashemi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The Vertical-Cavity Surface-Emitting Laser (VCSEL) made from GaAs-based materials is an established infrared light source, and is produced in large volumes for short-distance optical links, computer mice, and thermal processing systems. A wide range of applications, such as high-resolution printing, general lighting, and biomedical diagnosis and treatment could benefit from using a VCSEL with blue or ultraviolet emission. LÄS MER