Sökning: "Jonas Hellström"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Jonas Hellström.

  1. 1. Nanosecond optical parametric oscillators and amplifiers based on periodically poled KTiOPO4

    Författare :Jonas Hellström; KTH; []
    Nyckelord :optical parametric oscillators; optica parametric amplifiers; quasi-phasematching; KTiOPO4; nonlinear optics; frequency conversion; periodic electric field poling; ferroelectrics; high-order second harmonic generation; electro-optic effect;

    Sammanfattning : Optical parametric oscillators (OPOs) and optical parametricamplifiers (OPAs) constitute a class of optical frequencyconverting devices that have many possible applications, e.g.in range finding, molecular spectroscopy and medicine. LÄS MER

  3. 2. Novel materials for Yb and Er-Yb doped microchip lasers

    Författare :Jonas Hellström; Fredrik Laurell; Lars Sjöqvist; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; mid-IR lasers; laser materials; Optical physics; Optisk fysik;

    Sammanfattning : The objective of this thesis has been to investigate novel host material configurations for high-power end-pumped Er-Yb co-doped, or Yb doped microchip lasers and try to increase their performance. In Er-Yb co-doped systems, the main limitation is the thermal shortcomings of the phosphate glass host material. LÄS MER

  4. 3. On diode-pumped solid-state lasers

    Författare :Jonas Hellström; Fredrik Laurell; Valdas Pasiskevicius; Klaus Petermann; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; near-infrared lasers; end-pumped lasers; Q-switching; erbium; ytterbium; GdCOB; KGW; KYW; Co:MALO; laser materials; thermal lensing; end-pumping; spectroscopy; conical refraction; volume Bragg gratings; holographic gratings; laser tuning; Physics; Fysik;

    Sammanfattning : The research that is presented in this thesis can be divided into two major parts. The first part concerns longitudinally pumped, bulk Er-Yb lasers. In these lasers, the main limitation is the thermal shortcomings of the phosphate glass host material. LÄS MER

  5. 4. Knowledge for Improving Healthcare Service Quality : Combining Three Perspectives

    Författare :Jonas Boström; Johan Lilja; Ingela Bäckström; Helene Hillborg; Andreas Hellström; Mittuniversitetet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; quality; healthcare; knowledge; design thinking; improvement; professions;

    Sammanfattning : The Swedish public sector in general, and healthcare specifically, is struggling with large deficits: 19 of 21 regions have large negative results in 2019. The demands made by the citizens and their elected politicians that healthcare should offer effective, accessible, good and equal care are difficult to meet. LÄS MER

  7. 5. Numerical computations of the unsteady flow in a radial turbine

    Författare :Fredrik Hellström; Laszlo Fuchs; Jonas Bredberg; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Pulsatile flow; radial turbines; pipe flow; effects of inlet conditions; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : Non-pulsatile and pulsatile flow in bent pipes and radial turbine has been assessed with numerical simulations. The flow field in a single bent pipe has been computed with different turbulence modelling approaches. LÄS MER