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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.
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Study of properties of ultrashort femtosecond pulses
Hamráček, Karol ; Trojánek, František (advisor) ; Surýnek, Miloslav (referee)
Title: Study of the properties of ultra-short femtosecond pulses Author: Karol Hamráček Department: Department of chemical physics and optics Supervisor: doc. RNDr. František Trojánek, Ph.D. Abstract: Even as a bachelor thesis, the ultra-short pulses produced by the Rainbow CEP4 PRo laser system are about 7 fs long. This implies a very wide spectrum of these pulses, which can be up to 300 nm wide. This is why the ultrashort pulse will be lengthen by passing through a common dispersive medium such as the optical system of the classical optical elements, since each wavelength in the spectrum will propagate differently in the environment and will therefore overtake each other, resp. they will lag behind each other. Our aim will be to study this issue and to deal with the behavior of ultra-short pulses in different media. Keywords: ultra-short pulse, UV area, second harmonic wave
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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.
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Modulation of time dispersion of femtosecond laser pulses
Vyhlídka, Štěpán ; Straka, Petr (advisor) ; Ostatnický, Tomáš (referee)
In the presented thesis the topic of femtosecond pulse dispersion and methods of characterizing pulse profile are briefly introduced. Then, a functionality of a spatial light modulator is described. The spatial light modulator was used in an experimental scheme called the pulse shaper, which allowed independent amplitude and phase modulation of pulses. Duration and dispersion of pulses was measured by two methods called MIIPS and PICASO. MIIPS was also used for a reconstruction of a spectral phase of pulses. The autocorrelator was constructed on a design of the Mach-Zehnder interferometer. The duration of the shortest measured pulse (13.3 ± 0.5) fs was retrieved from measured interferometric autocorrelations by PICASO. Furthermore, theoretical dependence of pulse duration on the group delay dispersion was confirmed for pulses shorter than 120 fs. The group velocity dispersion was measured for fused silica windows and for a pair of diffraction gratings in the pulse shaper. Both values confirmed theoretical expectations.
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