Sökning: "laser-beams"

Visar resultat 1 - 5 av 17 avhandlingar innehållade ordet laser-beams.

  1. 1. Propagation of some coherent and partially coherent laser beams

    Författare :Yangjian Cai; Sailing He; Franco Gori; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; : dark hollow beam; elliptical Gaussian beam; flat-topped beam; twisted anisotropic Gaussian Schell-model; partial coherent; propagation; paraxial optical system; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : In this thesis, we investigate the propagation of some coherent and partially coherent laser beams, including a dark hollow beam (DHB), an elliptical Gaussian beam (EGB), a flat-topped beam and a twisted anisotropic Gaussian Schell-model (TAGSM) beam, through a paraxial optical system or a turbulent atmosphere. Several theoretical models are proposed to describe a DHB of circular or non-circular symmetry. LÄS MER

  3. 2. Interaction mechanisms of pulsed laser beams at different wavelengths with matter

    Författare :Olga Yalukova; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Manufacturing Systems Engineering; Produktionsutveckling;

    Sammanfattning : This thesis presents an investigation of the interaction mechanism involved in processing of different engineering materials using pulsed TEA CO2- and Nd:YAG lasers. Several methods were used. Digital Speckle Photography (DSP) or Speckle Correlation was used to detect micro-structural changes in the material surface during laser irradiation. LÄS MER

  4. 3. Laser-Based Techniques for Combustion Diagnostics

    Författare :Nikola Georgiev; Förbränningsfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; LIF; Laser-based diagnostic techniques; PS; DFWM; Fysik; Fysicumarkivet A:1997:Georgiev;

    Sammanfattning : Two-photon-induced Degenerate Four-Wave Mixing, DFWM, was applied for the first time to the detection of CO, and NH3 molecules. Measurements were performed in a cell, and in atmospheric-pressure flames. In the cell measurements, the signal dependence on the pressure and on the laser beam intensity was studied. LÄS MER

  5. 4. Laser cooling mechanisms and Brownian motors in optical lattices

    Författare :Peder Sjölund; Anders Kastberg; Svante Jonsell; Chris Westbrook; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Optical physics; Optisk fysik;

    Sammanfattning : Denna avhandling innefattar såväl experimentella som numeriska studier av laserkylda atomer i optiska kristallgitter. Bland annat har laserkylningsprocesser studerats, där atomers rörelser i optiska kristallgitter har uppvisat andra typer av bakomliggande mekanismer än de som tidigare förutsågs genom “Sisyfoskylningsmodellen”. LÄS MER

  7. 5. DEVELOPMENT OF A HIGH ENERGY TI:SAPPHIRE LASER FOR THE EXCITATION OF EXTREME ULTRAVIOLET LASERS

    Författare :Dale Martz; Jorge Rocca; Colorado State University; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; SRA - E-vetenskap SeRC ; SRA - E-Science SeRC ;

    Sammanfattning : This dissertation describes the design, construction and characterization of a high energy chirped-pulse amplification Titanium-Sapphire laser system for the excitation of Extreme Ultraviolet (EUV) lasers. Compact EUV lasers have made possible nano-scale imaging, dense plasma diagnostics and photo-chemistry and photo-physics studies. LÄS MER