|
|
Selection of femtosecond laser pulses
Bažíková, Sára ; Trojánek, František (advisor) ; Zázvorka, Jakub (referee)
Construction of the laser is one of the most important physical advances of modern times. Its use in practice is extremely common and desirable, therefore, it is necessary to push the boundaries of possibilities of this technique still further. Lasers generating ultrashort pulses are widely used in material research for the study of nonlinear effects and ultrafast processes. These lasers have a high repetition rate, which must be reduced for some applications. In this thesis we used femtosecond titanium -sapphire laser from Spectra Physics, whose repetition rate is 80 MHz. The aim of this thesis is to reduce this frequency by using a pulse selector. The key mechanism that utilizes the pulse selector is an acoustooptic modulator that is based on the principle of Bragg diffraction and it is able to select pulses with a frequency of 1 Hz-4 MHz. The end of thesis is measurement of the properties of this selector and its optimization.
|
|
|
Femtosecond laser spectroscopy of diamond
Bažíková, Sára ; Malý, Petr (advisor) ; Preclíková, Jana (referee)
Due to its extraordinary features and wide bandwidth (5.47 eV), diamond is a very promising material in the field of optoelectronics. By absorbing ultraviolet light, excited charge carriers - electrons and holes - are created in the diamond, which can create excitons due to mutual Coulomb interaction. For low temperatures and high concentrations of photoexcitated carriers, carriers can condense into electron-hole droplets and form an electron-hole liquid. The aim of this diploma thesis is to follow up with previous research at the department and to examine the dynamics of electron-hole liquid in bulk diamond at low temperatures. Using femtosecond laser spectroscopy, we investigate the influence of excitation wavelengths on the dynamics of electron-hole liquid condensation.
|
|
|
Selection of femtosecond laser pulses
Bažíková, Sára ; Trojánek, František (advisor) ; Zázvorka, Jakub (referee)
Construction of the laser is one of the most important physical advances of modern times. Its use in practice is extremely common and desirable, therefore, it is necessary to push the boundaries of possibilities of this technique still further. Lasers generating ultrashort pulses are widely used in material research for the study of nonlinear effects and ultrafast processes. These lasers have a high repetition rate, which must be reduced for some applications. In this thesis we used femtosecond titanium -sapphire laser from Spectra Physics, whose repetition rate is 80 MHz. The aim of this thesis is to reduce this frequency by using a pulse selector. The key mechanism that utilizes the pulse selector is an acoustooptic modulator that is based on the principle of Bragg diffraction and it is able to select pulses with a frequency of 1 Hz-4 MHz. The end of thesis is measurement of the properties of this selector and its optimization.
|
guest ::
