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Visar resultat 1 - 5 av 16 avhandlingar som matchar ovanstående sökkriterier.

  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. Numerical Methods for Wave Propagation : Analysis and Applications in Quantum Dynamics

    Författare :Emil Kieri; Sverker Holmgren; Vasile Gradinaru; Hans O. Karlsson; Tobias Jahnke; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; computational wave propagation; quantum dynamics; time-dependent Schrödinger equation; spectral methods; Gaussian beams; splitting methods; low-rank approximation; Scientific Computing; Beräkningsvetenskap;

    Sammanfattning : We study numerical methods for time-dependent partial differential equations describing wave propagation, primarily applied to problems in quantum dynamics governed by the time-dependent Schrödinger equation (TDSE). We consider both methods for spatial approximation and for time stepping. LÄS MER

  4. 3. Development of a generalized Gaussian model for absorbed dose calculation and dose planning in therapeutic electron beams

    Författare :Ingmar Lax; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : .... LÄS MER

  5. 4. Topics in Analysis and Computation of Linear Wave Propagation

    Författare :Mohammad Motamed; Olof Runborg; Shi Jin; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical analysis; Numerisk analys;

    Sammanfattning : This thesis concerns the analysis and numerical simulation of wave propagation problems described by systems of linear hyperbolic partial differential equations. A major challenge in wave propagation problems is numerical simulation of high frequency waves. LÄS MER

  7. 5. Modeling and Characterization of nonlinear Materials for Protection of Optical Sensors

    Författare :Anders Eriksson; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis concerns nonlinear materials and experimental techniques for optical power limiting applications. Theoretical models to analyze and simulate related measurements were studied. Two different numerical modeling tools for propagation of optical radiation through optically nonlinear media were developed. LÄS MER