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Ultrafast highly nonlinear processes in diamond
Zukerstein, Martin ; Trojánek, František (advisor) ; Kloz, Miroslav (referee) ; Kužel, Petr (referee)
Intense few-cycle laser pulses can significantly affect the properties of transparent solids during the interaction. These processes take place on femtosecond time scales and they can be studied using ultrafast spectroscopic methods. This dissertation deals with highly nonlinear processes in diamond. In the interaction with a crystalline diamond, we observed a strong nonlinear broadening of the spectrum due to self-phase modulation effect, which allowed us to create a simple technique for compression of pulses from laser oscillator. At the same time, strongly nonlinear five-photon absorption was observed, in which we found a significant anisotropy and dependence on the polarization state. With two-beam pump and probe experiments we present a study of anharmonic phenomena in the dynamics of coherent phonons in diamond, additionally we created a new detection technique of lattice vibrations using multiphoton absorption. Finally, the high time resolution of the experiments revealed that the sub-picosecond electron dynamics strongly depends on the composition and morphology of the polycrystalline diamond thin films. The experimental results of this work provide comprehensive research into the interaction of diamond with few-cycle laser pulses and the development of new spectroscopic methods.
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Energy transfer pathways in reconstituted peridinin chlorophyll complexes
KLOZ, Miroslav
The main objective of this thesis is to study energy transfer pathways between carotenoids and chlorophylls in the reconstituted light harvesting protein, peridinin chlorophyll protein (PCP), of the marine dinoflagellate Amphidinium carterae. The reconstituted PCP complex contains either bacteriochlorophyll-a or a mixture of bacteriochlorophyll-a and chlorophyll-b instead of chlorophyll-a that occurs in the native PCP. The introduction and methods of the thesis describes spectroscopic properties of carotenoids with emphasis on the carotenoid peridinin, and a brief introduction to the femtosecond pump probe spectroscopy and global fitting analysis used for treating the time resolved spectra. The main results, dependence of the peridinin to bacteriochlorophyll-a energy transfer pathways on excitation wavelength and energy transfer between chlorophylls, are described and discussed in the results of the thesis. Prohlašuji, že svoji diplomovou práci jsem vypracoval samostatně pouze s použitím pramenů a literatury uvedené v seznamu citované literatury. Prohlašuji, že v souladu s § 47b zákona č.111/1998 SB. v platném znění souhlasím se zveřejněním své diplomové práce, a to v nezkrácené podobě elektronickou cestou ve veřejně přístupné části databáze STAG provozované Jihočeskou univerzitou v Českých Budějovicích a na jejích internetových stránkách.
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