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Preparation and characterization of novel molecular materials for nonlinear optics
Mathauserová, Jana ; Němec, Ivan (advisor) ; Nižňanský, Daniel (referee)
The main issue of this bachelor thesis is the investigation of salts and cocrystals of biuret and 2-aminopyrimidine in consideration of their usage in the field of nonlinear optics. The first attempt of this thesis was preparation of compounds combining biuret with organic or inorganic acids, urea and biguanide. The second part is focused on the searching of new salts of 2-aminopyrimidine and on further characterisation of its formerly prepared compounds. The methods employed to investigate the prepared materials include vibrational spectroscopy and X-ray diffraction analysis. The theoretical quantum mechanical calculations were used to predict the nonlinear optical properties of selected molecules and also for the interpretation of the recorded vibrational spectra. Measurements of second harmonic generation efficiency of selected powder samples were performed.
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Investigation of new materials for second harmonic generation
Brajer, Martin ; Němec, Petr (advisor) ; Žídek, Karel (referee)
In these bachelor thesis optical properties of materials are studied. This materials are purposefully prepared for effective second harmonic generation (SHG) and for its usage in optoelectronics. Specificely we will measure the first hyperpolarizibility. Non-coherent phenomenon of hyper-Rayleigh scattering will be used. Considering its incoherence, the effect is very weak. It's necessary to use a strong source of light, pulse laser and a sensitive detection device, photomultiplier. Samples are prepared in cooperating chemical laboratories of Faculty of Science of Charles University in Prague. Additionally, we will discuss participation of two-photon fluorescence in output intensity because of its interchangeability with SHG.
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Preparation and study of novel crystalline materials for nonlinear optics based on nitrogen-containing heterocycles
Kloda, Matouš ; Němec, Ivan (advisor) ; Schwendt, Peter (referee) ; Holubová, Jana (referee)
The presented Ph.D. thesis is aimed at the preparation and characterisation of novel crystalline materials with application potential in nonlinear optics (NLO). The main goal was preparation of crystalline salts and adducts (cocrystals) of selected nitrogen-containing heterocycles with a range of organic and inorganic acids. Based on previous study and quantum- chemical calculations, the following starting heterocycles were selected: 2-aminopyrimidine, 4-aminopyrimidine, 5-aminopyrimidine, 3-amino-1,2,4-triazine and 3-amino-5,6-dimethyl- 1,2,4-triazine. The prepared materials were characterised mainly by X-ray diffraction and vibrational spectroscopy and the interpretation of the vibrational spectra was based on quantum-chemical calculations. The systems based on aminopyrimidines were the first field of study in presented thesis. The thesis represents a finalisation of our previous study focused on inorganic salts and cocrystal in the case of 2-aminopyrimidine. The characterisation of a pair of cocrystals with boric acid was accomplished. The 12 new salts and adducts were prepared and characterised in the case of 4-aminopyrimidine and only one crystalline product - adduct with succinic acid - was obtained in the case of 5-aminopyrimidine. The systems based on 3-amino-1,2,4-triazine and its...
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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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Generation of carrier-envelope-stable few-cycle pulses in the mid-infrared spectral region
Peterka, Pavel ; Kozák, Martin (advisor) ; Žídek, Karel (referee)
In this thesis we present the realization of a source of 1.5-cycle carrier-envelope phase stable laser pulses in the mid-infrared spectral region. We used ytterbium laser system generating 1 µm pulses as a pump of setup, where the beam is split into several parts and interact in nonlinear optical media. 2 µJ pulses with duration 18 fs at 50 kHz repe- tition rate are produced. By spectral broadening in crystal GGG, 9,9 fs pulses can be achieved. The mid-IR pulses was characterized by third harmonics generation frequency resolved optical gating in the interferometric configuration. Fourier filtering of the mea- sured interferogram allows for the complete reconstruction of amplitude and phase of the ultrashort pulses generated by our setup. The pulses will in future serve for experimental investigation of ultrafast strong-field phenomena in solids. 1
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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...
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Preparation and study of novel crystalline materials for nonlinear optics based on nitrogen-containing heterocycles
Kloda, Matouš ; Němec, Ivan (advisor) ; Schwendt, Peter (referee) ; Holubová, Jana (referee)
The presented Ph.D. thesis is aimed at the preparation and characterisation of novel crystalline materials with application potential in nonlinear optics (NLO). The main goal was preparation of crystalline salts and adducts (cocrystals) of selected nitrogen-containing heterocycles with a range of organic and inorganic acids. Based on previous study and quantum- chemical calculations, the following starting heterocycles were selected: 2-aminopyrimidine, 4-aminopyrimidine, 5-aminopyrimidine, 3-amino-1,2,4-triazine and 3-amino-5,6-dimethyl- 1,2,4-triazine. The prepared materials were characterised mainly by X-ray diffraction and vibrational spectroscopy and the interpretation of the vibrational spectra was based on quantum-chemical calculations. The systems based on aminopyrimidines were the first field of study in presented thesis. The thesis represents a finalisation of our previous study focused on inorganic salts and cocrystal in the case of 2-aminopyrimidine. The characterisation of a pair of cocrystals with boric acid was accomplished. The 12 new salts and adducts were prepared and characterised in the case of 4-aminopyrimidine and only one crystalline product - adduct with succinic acid - was obtained in the case of 5-aminopyrimidine. The systems based on 3-amino-1,2,4-triazine and its...
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Novel technique for characterization of ultrashort optical pulses
Peterka, Pavel ; Kozák, Martin (advisor) ; Ostatnický, Tomáš (referee)
Ultrashort laser pulses are nowadays widely used in both the basic and applied reseach as well as in a wide range of applications. Application of laser pulses requires their complete characterization from the point of view of temporal evolution of field amplitude and frequency on femtosecond timescales. This thesis is focused on a new method for ultrashort pulse characterization, which involves measuring spectral interference between input pulse and the pulse transmitted through a medium with cubic nonlinear susceptibility. The new method is inte- resting compared to the established techniques mainly because of its simplicity, as it requires only one medium with cubic nonlinear susceptibility and a spectro- meter. We have implemented the technique experimentally and determined pulse duration and phase for ideally compressed pulse.
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Synthesis and study of crystalline materials for NLO
Janatková, Tereza ; Němec, Ivan (advisor) ; Vojtíšek, Pavel (referee)
This thesis is focused on preparation and study of new compounds of chosen organic bases with potential use in nonlinear optics. 2-amino-5-nitropyrimidine, 2-amino-4-methylpyrimidine and their salts with inorganic and organic acids are compounds of the main interest. Diffraction and vibrational-spectroscopic methods of characterization were used in combination with quantum chemical calculation methods. Another aim of this thesis was preparation of new salts of chosen pyrimidine derivates with the use of methylsulphonic acid. Part of this section is devoted to completion of pyridinium methylsulphonate phase transition and nonlinear optical property studies.
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High-average power picosecond mid-IR source
Vyvlečka, Michal ; Novák, Ondřej (advisor) ; Trojánek, František (referee)
1 Title: High-average power picosecond mid-IR source Author: Michal Vyvlečka Department: Department of Chemical Physics and Optics Supervisor: Ing. Ondřej Novák, Ph.D., Hilase centre, Institute of Physics of CAS Abstract: High average power wavelength tunable picosecond mid-IR source based on optical parametric generation (OPG) and optical parametric amplification (OPA) is being developed. The conversion system is pumped by an Yb:YAG thin-disk laser delivering 100 W of average power at 100 kHz repetition rate, 1030 nm wavelength, and 2-3 ps pulse width. Part of this fundamental beam pumps an OPG process in a PPLN crystal. The generated wavelength is determined by PPLN's poling period and temperature. Tunability of the signal wavelength between 1.46 µm and 1.95 µm was achieved, the signal beam of 20 mW was generated at 2 W of pump power, when double pass of the beams through PPLN crystal was used. The corresponding idler wavelengths were in range 2.18-3.50 μm. The signal beam was further amplified by OPA process in two KTP crystals, which was pumped by the fundamental beam. The signal beam was amplified up to 2 W at pumping of 38 W. Tuning of the output wavelength was realized by change of the phase-matching angle in KTP crystals. Tunability between 1.70-1.95 µm for signal and 2.18-2.62 µm for idler was...
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