National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
Nonlinear optical frequency conversion of few-cycle laser pulses
Koutenský, Petr ; Kozák, Martin (advisor) ; Galář, Pavel (referee)
Title: Nonlinear optical frequency conversion of few-cycle laser pulses Author: Petr Koutenský Department: Department of Chemical Physics and Optics Supervisor: RNDr. Martin Kozák, Ph.D., Department of Chemical Physics and Optics Abstract: The goal of the thesis was to achieve generation of second harmonic frequency from ultrashort laser pulses with central wavelength of 780 nm and to compress the generated pulses to the shortest possible time duration. We have studied and optimized the efficiency of second harmonic frequency generation from wide spectrum laser, which generates ultrashort pulses with a duration of few femtoseconds. Firstly we have developed and optimized the experimental setup for the highest power output of the generated second harmonic frequency pulses. Afterwards we measured the duration of the generated pulses using nonlinear optical cross- correlation with the pulses at the fundamental frequency generated by the laser. Cross- correlation was obtained from sum frequency generation in a thin nonlinear BBO crystal. The pulses at the second harmonic frequency were compressed to a duration of 13 femtoseconds by combining wide spectrum mirrors with negative dispersion of group velocities and thin fused silica wedges. These ultrashort pulses will be used in experiments with high time...
Sum-frequency generation in far-UV spectral region
Martínek, Miroslav ; Kozák, Martin (advisor) ; Ondič, Lukáš (referee)
Nonlinear optics is the area of high field optics, where the dependence of polarization of matter on the electric field of optical radiation cannot be considered as linear. This has important implications for practise, since the superposition principle is no longer valid in nonlinear optics. Thus it is possible to influence light, propagating through material, by another intensive radiation. Nonlinear optical phenomena are important especially for laser technology because they allow to generate light at different wavelengths using various interactions. This thesis is focused on the study of the sum-frequency generation in the far ultraviolet (UV) region of the spectrum. As the radiation source the femtosecond laser system was used. The aim of the study was to theoretically describe generation by nonlinear wave equation and to calculate the dependence of phase-matching angle on generated wavelength. Theoretical results were then verified experimentally in the laboratory. Also the energy of generated pulses and sum-frequency generation efficiency were measured for pulses in spectral region 215-250 nm. The generated pulses will further serve to excite electron-hole pairs in the diamond.

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