Sökning: "Second Harmonic Generation"

Visar resultat 16 - 20 av 69 avhandlingar innehållade orden Second Harmonic Generation.

  1. 16. Domain engineering in KTiOPO4

    Författare :Carlota Canalias; Fredrik Laurell; Benoît Boulanger; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quasi-phase matching; KTiOPO4; ferroelectric domains; atomic force microscopy; periodic electric field poling; polarization switching; second harmonic generation; Optical physics; Optisk fysik;

    Sammanfattning : Ferroelectric crystals are commonly used in nonlinear optics for frequency conversion of laser radiation. The quasi-phase matching (QPM) approach uses a periodically modulated nonlinearity that can be achieved by periodically inverting domains in ferroelectric crystals and allows versatile and efficient frequency conversion in the whole transparency region of the material. LÄS MER

  3. 17. Theoretical perspectives on ultrafast and non-linear spectroscopy

    Författare :Emil Vinas Boström; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Non-linear optics; Ultrafast dynamics; Non-equilibrium Green s functions; Density functional theory; Multi-photon absorption; Second harmonic generation; Desorption dynamics; Auger decay; Charge-separation dynamics; Quantum Zeno effect; Fysicumarkivet A:2018:Vinas Boström;

    Sammanfattning : In this thesis we discuss a theoretical description of ultrafast and non-linear spectroscopy. Due to the high intensities and ultrashort pulse durations involved in such experiments, it is necessary to use an explicitly time-dependent formalism. LÄS MER

  4. 18. Fabrication and characterization of periodically poled KTB and RB-doped KTB for applications in the visible and UV

    Författare :Shunhua Wang; Fredrik Laurell; Peter Smith; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nonlinear optics; second-harmonic generation; quasi-phasematching; type-I QPM SHG; type-II QPM SHG; KTP; RKTP; periodic electric-field poling; Physics; Fysik;

    Sammanfattning : This thesis deals with the fabrication and the characterization of periodically-poled crystals for use in lasers to generate visible and UV radiation by second-harmonic generation (SHG) through quasi-phasematching (QPM). Such lasers are of practical importance in many applications like high-density optical storage, biomedical instrumentation, colour printing, and for laser displays. LÄS MER

  5. 19. Acoustical Measurements of Material Nonlinearity and Nonequilibrium Recovery

    Författare :Kristian Haller; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear acoustics; nondestructive testing; activation density; slow dynamics; nonequilibrium recovery; resonance frequency; nonlinear wave modulation spectroscopy; harmonic generation; trapped modes; open resonator; sweep rate; constant strain sweep;

    Sammanfattning : A damaged material or a material with non perfect atomic geometry, dislocations or cracks, exhibits two types of characteristic responses to acoustic excitations. First is the fast nonlinear dynamics response that is present as long as the material is excited. As soon as the excitation stops the response disappear. LÄS MER

  7. 20. Blue Laser Source for Laser-Induced Fluorescence

    Författare :Jesper Holm; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Second Harmonic Generation; Lasers; PPKTP; ALA; Tapered laser diodes; External cavity lasers; Laser-induced fluorescence; photodynamic therapy; mTHPC;

    Sammanfattning : Laser-induced fluorescence is a clinical diagnostic tool, used for tumor demarcation and detection. The technique relies on the injection or topical application of a light sensitive drug called a photosensitizer. This substance has the ability to be accumulated to higher concentrations in cancer cells than in normal cells. LÄS MER