National Repository of Grey Literature 7 records found  Search took 0.00 seconds. 
Femtosecond absorption spectroscopy for study of stimulated emission
Streshkova, Neli ; Malý, Petr (advisor) ; Zukerstein, Martin (referee)
The aim of the thesis is the building and optimization of an experimental setup for me- asuring the transient transmission and optical gain by the femtosecond pump and probe technique. The setup combines the technology of parametric generation of pump pulses with tunable wavelength and the generation of femtosecond continuum as a spectrally wide probe. In the thesis, conditions of supercontinuum generation in bulk fused silica are extensively studied from a practical viewpoint. The performance of the setup was tested on two types of samples: the solution of rhodamine 6G in methanol and the semiconduc- tor nanocrystalline sample - CdSSe-doped glass. Time resolved spectra of the transient transmission of both samples were measured and the spectral dependence of the optical gain in rhodmine 6G was obtained. 1
Laser spectroscopy of crystalline and nanocrystalline diamond
Zukerstein, Martin ; Trojánek, František (advisor)
The aim of this thesis is a study of NV centres in crystalline and nanocrystalline diamond by laser spectroscopy methods. In the theoretical part we discuss the laser spectroscopy methods, the studied material - diamond and the NV colour centres. In the experimental part we discuss the influence of nanoparticle size on luminescence spectra. We measure the luminescence of samples at room and also at low temperatures depending on the intensity and wavelength of the excitation. We study the photo-conversion of negatively charged state of NV centres to the neutral in detail. We make the time resolved measurements of the luminescence on streak camera for characterization the dynamical properties of the studied samples. The result is the comparison of lifetimes of the states in NV centres in selected samples.
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.
Femtosecond absorption spectroscopy for study of stimulated emission
Streshkova, Neli ; Malý, Petr (advisor) ; Zukerstein, Martin (referee)
The aim of the thesis is the building and optimization of an experimental setup for me- asuring the transient transmission and optical gain by the femtosecond pump and probe technique. The setup combines the technology of parametric generation of pump pulses with tunable wavelength and the generation of femtosecond continuum as a spectrally wide probe. In the thesis, conditions of supercontinuum generation in bulk fused silica are extensively studied from a practical viewpoint. The performance of the setup was tested on two types of samples: the solution of rhodamine 6G in methanol and the semiconduc- tor nanocrystalline sample - CdSSe-doped glass. Time resolved spectra of the transient transmission of both samples were measured and the spectral dependence of the optical gain in rhodmine 6G was obtained. 1
Laser spectroscopy of crystalline and nanocrystalline diamond
Zukerstein, Martin ; Trojánek, František (advisor)
The aim of this thesis is a study of NV centres in crystalline and nanocrystalline diamond by laser spectroscopy methods. In the theoretical part we discuss the laser spectroscopy methods, the studied material - diamond and the NV colour centres. In the experimental part we discuss the influence of nanoparticle size on luminescence spectra. We measure the luminescence of samples at room and also at low temperatures depending on the intensity and wavelength of the excitation. We study the photo-conversion of negatively charged state of NV centres to the neutral in detail. We make the time resolved measurements of the luminescence on streak camera for characterization the dynamical properties of the studied samples. The result is the comparison of lifetimes of the states in NV centres in selected samples.
Laser spectroscopy of crystalline and nanocrystalline diamond
Zukerstein, Martin ; Trojánek, František (advisor) ; Preclíková, Jana (referee)
The aim of this thesis is a study of NV centres in crystalline and nanocrystalline diamond by laser spectroscopy methods. In the theoretical part we discuss the laser spectroscopy methods, the studied material - diamond and the NV colour centres. In the experimental part we discuss the influence of nanoparticle size on luminescence spectra. We measure the luminescence of samples at room and also at low temperatures depending on the intensity and wavelength of the excitation. We study the photo-conversion of negatively charged state of NV centres to the neutral in detail. We make the time resolved measurements of the luminescence on streak camera for characterization the dynamical properties of the studied samples. The result is the comparison of lifetimes of the states in NV centres in selected samples.
Multiphoton absorption of ultrafast laser pulse
Zukerstein, Martin ; Trojánek, František (advisor) ; Schmoranzerová, Eva (referee)
Nonlinear optics is constantly developing and in terms of future applications very perspective field of physics. With high-intensity pulsed lasers we are able to study interesting phenomena in matter that we cannot observe with common sources of light. The aim of this thesis is a study of the multiphoton absorption of high-intensity pulses in diamond using z-scan technique. It theoretically describes this nonlinear phenomenon using quantum theory. The next section author took a measurement of the two-photon absorption and found the two-photon absorption coefficients in different samples. Diamond was chosen as the sample material. This material has absolutely unique properties that rank it highly in future applications for optoelectronic devices.

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