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Visar resultat 1 - 5 av 7 uppsatser som matchar ovanstående sökkriterier.

  1. 1. Numerical simulations of ultrafast dynamics in plasmonic nanostructures

    Uppsats för yrkesexamina på avancerad nivå, Umeå universitet/Institutionen för fysik

    Författare :Nils Henriksson; [2023]
    Nyckelord :Ultrafast nanophotonics; Three temperature model; Numerical simulations;

    Sammanfattning : Plasmonic effects in nanosized particles enhance the interaction between light and matter due to the localized surface plasmon resonance, with potential applications such as all-optical transistors and optical computers. Commonly, the dynamics of nanoparticles’ optical properties are assessed via pump-probe spectroscopy, where a plasmonic structure is exited by an initial laser, the pump. LÄS MER

  3. 2. Study of the vibronic mixing in chlorophylls with multidimensional spectroscopy

    L3-uppsats, Lunds universitet/Kemiska institutionen

    Författare :Ignacio Martínez Casasús; [2021]
    Nyckelord :Two-dimensional spectroscopy; Ultrafast spectroscopy; Chlorophyll a; Chlorophylls; Photosynthesis; Light harvesting; Vibronic mixing; Quantum coherence; Chemical physics; Chemistry;

    Sammanfattning : Chlorophylls comprise one of the most important families of molecules for the photosynthetic process. Chlorophyll-like molecules have been classically interpreted under the Gouterman model, being thought to feature two independent transitions, Qy(S1) and Qx(S2). LÄS MER

  4. 3. Dependency of high-order harmonics to polarisation properties of many-cycle driving fields

    Master-uppsats, Lunds universitet/Atomfysik; Lunds universitet/Fysiska institutionen

    Författare :Timothé Ramboazanaka; [2018]
    Nyckelord :Atomic physics; attosecond pulses; high-order harmonic generation; polarisation; polarisation state; electron wave packet trajectory; three-step model; time-dependent schrödinger equation; TDSE; two-colour; selection rules; symmetry; conservation laws; Physics and Astronomy;

    Sammanfattning : Light-matter interactions can be used to probe both light and matter as they yield information on a system's state. On the ultrafast timescale, it is possible to employ these interactions to probe fast-occurring phenomena. LÄS MER

  5. 4. Evaluation of white-light generation as possible seed for a mid-infrared optical parametric chirped pulse amplifier

    Master-uppsats, Lunds universitet/Fysiska institutionen; Lunds universitet/Kärnfysik

    Författare :Chuang Lu; [2017]
    Nyckelord :nonlinear linear optics; ultrafast optics; Mid-infrared generation; near-infrared; Optical parametric amplification; Optical Parametric Chirped-pulse Amplification; supercontinuum generation; white-light generation; laser induced filamentation; Dispersion-scan; nonlinear propagation; Physics and Astronomy;

    Sammanfattning : White-light spectra of different crystals, based on 1030-nm intense pump pulses have been investigated in order to derive a near-infrared seed for mid-infrared generation. Among ten crystals, YAG (yttrium aluminium garnet), KGW (potassium gadolinium tungstate) and YVO4 (yttrium orthovanadate) exhibit the most suitable properties for supercontinuum generation with high efficiency for spectral broadening as well as high tolerance to optical damage. LÄS MER

  7. 5. Investigating the stability of a laser-based plasma x-ray source

    Kandidat-uppsats, Lunds universitet/Kemisk fysik; Lunds universitet/Fysiska institutionen

    Författare :Fredrik Parnefjord Gustafsson; Jens Uhlig; Wilfred Fullagar; Amal El Nahhas; [2016]
    Nyckelord :pulse energy; pointing; TES; transmission-edge-sensor; EXAFS; spectrum; spectroscopy; absorption; emission; time-resolved; Brunel mechanism; vacuum heating; water-jet; CCD; andor; LPXS; x-ray; plasma; laser; fluctuations; stability; pixel detector; beam profile sensor; resonant absorption; beam position; Physics and Astronomy;

    Sammanfattning : The use of laser based plasma x-ray sources (LPXS) has quickly expanded during the past decades due to rapid development of ultrafast laser systems. These sources are used in many research applications such as emission, absorption and particularly time-resolved spectroscopy. LÄS MER