Sökning: "picosecond laser"

Visar resultat 1 - 5 av 37 avhandlingar innehållade orden picosecond laser.

  1. 1. Development and Application of Single-Ended Picosecond Laser Diagnostics

    Författare :Billy Kaldvee; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Raman Scattering; Temporal Filtering; Picosecond Laser Diagnostics; Rayleigh Scattering; Laser-spectroscopy; DIAL; Laser Combustion Diagnostics; Lidar; Laser-induced Fluorescence; Laser-induced Incandescence; Fysicumarkivet A:2012:Kaldvee;

    Sammanfattning : Light detection and ranging (lidar), a method for nonintrusive, single-ended, and range resolved measurements, has been developed and applied for combustion related diagnostics. Employing picosecond laser pulse durations and detectors providing temporal resolution on the order of picoseconds, lidar has been applied successfully for both quantitative temperature- and species concentration measurements, obtaining an ultimate range resolution of 0. LÄS MER

  3. 2. Novel Technologies for Mode-Locking of Solid-State Lasers

    Författare :Niels Meiser; Valdas Pasiskevicius; Steinmeyer Günter; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; laser; mode-locked laser; pulsed laser; quantum dot; carbon nanotube; nonlinear optics; saturable absorber; Kerr-lens mode-locking; ultra-fast laser; picosecond laser; pulsed laser; semiconductor saturable absorber;

    Sammanfattning : The subject of this thesis is the investigation of novel technologies for mode-locking of diode-pumped, solid-state lasers. Novel saturable absorbers are used: quantum dots (QDs) and carbon nanotubes (CNTs), which both are low-dimensional nano-formations. In addition, mode-locking by cascaded nonlinearities is explored. LÄS MER

  4. 3. Laser Diagnostics in Combustion - Elastic Scattering and Picosecond Laser-Induced Fluorescence

    Författare :Frederik Ossler; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Spray; Picosecond laser; Streak camera; Time resolved; Fluorescence lifetimes; 3 – D flow imaging; 2 - D lifetime imaging; Pressure; Temperature; Hydrogen atoms; Oxygen atoms; 3-pentanone; Acetone; Lorenz-Mie theory; Aerosol; Fysicumarkivet A:1999:Ossler; Scattering; Fysik; Physics; Polycyclic aromatic hydrocarbons.;

    Sammanfattning : Elastic scattering and the Lorenz-Mie (LM) theory in particular is used for the characterization of sub-micron- and micron-sized droplets of organic fuels in sprays and aerosols. Calculations on the Lorenz- Mie theory show that backward-sideward scattered visible radiation can be used for unambiguous detection of ensembles of homogeneous droplets of organic substances with diameters around 1 micrometer (size parameter between 2 and 6). LÄS MER

  5. 4. Nonlinear optical techniques for ultrafast laser diagnostics : Development of femtosecond LIF, LIGS, CARS and backward lasing

    Författare :Maria Ruchkina; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; laser diagnostics; femtosecond laser; nonlinear interactions; ultrafast spectroscopy; multi-photon excitation; laser-induced fluorescence; rotational coherent anti-Stokes Raman spectroscopy; laser-induced grating spectroscopy; lasing; backward lasing technique; Fysicumarkivet A:2021:Ruchkina;

    Sammanfattning : The thesis work concerns development and application of four versatile nonlinear optical techniques, based on exploiting ultrashort laser pulses, for diagnostic purposes in gases and flames. The four techniques, all laser-based, are two-photon laser-induced fluorescence (TPLIF), hybrid femtosecond/nanosecond (fs/ns) rotational coherent anti-Stokes Raman scattering (fs/ns RCARS), fs-laser-induced grating spectroscopy (fs-LIGS), and backward lasing. LÄS MER

  7. 5. Towards Quantitative Diagnostics using Short-Pulse Laser Techniques

    Författare :Andreas Ehn; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; PicoSecond Laser Diagnostics; Raman Scattering; Photo Fragmentation; Fluorescnece Lifetime Imaging; Temporal Filtering; Fysicumarkivet A:2012:Ehn; LIDAR; Laser-Induced Fluorescence;

    Sammanfattning : Laser based diagnostic tools have had an exploding impact on fundamental as well as applied research in a number of disciplines, such as biomedicine, physical chemistry etc over the last decades. Whereas fundamental research often investigate phenomena in extreme conditions, applied research aims at performing in-situ measurements, in order to understand the many aspects and entangled phenomena that affects the research of interest. LÄS MER