National Repository of Grey Literature 16 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Porovnání sklízecích mlátiček John Deere s tangenciálním a axiálním mlátícím ústrojím T670i a S770
PETERKA, Pavel
The bachelor thesis deals with the comparison of tangential and axial threshers in terms of price, threshing quality, losses and performance. The thesis explains the description and technology of individual threshing and their principles. The following is a description of other operations performed by the combine during its operation (during the season). Attention is also paid to automation, which is reflec-ted in the assessed issues.
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
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.
The changes of ski infrastructure and its use in the Krušné hory in the last decade
Peterka, Pavel ; Fialová, Dana (advisor) ; Vágner, Jiří (referee)
The theme of my thesis is focused on downhill skiing which together with cross country skiing is the most important activity of winter tourist season. The downhill skiing has got a long tradition in the Czech Republic and there are a large number of ski resorts. One of the most important regions of downhill skiing in the Czech Republic is Krušné Hory. The development of tourism in the Krušné hory is very specific compared to other Czech mountains. After 1948, some parts of the territory inaccessible, as it was a border zone and in the following years they were destroyed by coal mining. The thesis analyzes the changes that were caused over many years in the Krušné Hory. This thesis is focused on the last ten years. The second part of the questionnaire survey shows the potential of the Krušné hory which is used by the schools in Ústí nad Labem. The main aim of the questionnaire was to find out where the schools from Ústí nad Labem organize their ski courses and what are the main priorities for the selection of the locality.
Fiber lasers
Peterka, Pavel
Fiber lasers are one of the most spectacular achievements of contemporary optoelectronics and photonics. Variety of fiber lasers were demonstrated ranging from mighty continuous-wave systems with multi-kilowatt output powers to elegant femtosecond-pulse sources for precise frequency and time measurements. In the contribution, we present basic principles and applications of these new sources of laser radiation and we present selected research results in this field in the Institute of Photonics and Electronics.
Estimation of energy transfer parameters in thulium- and ytterbium-doped silica fibers
Peterka, Pavel ; Blanc, W. ; Dussardier, B. ; Monnom, G. ; Simpson, D. A. ; Baxter, G.
We present an estimation of the energy transfer coefficients by comparison of the measured emission of three TYDF samples with numerical simulations of the respective emission. The energy transfer coefficients were found higher than those reported in Tm/Yb-doped fluoride based crystals. With possible improvement of excited level lifetime of thulium by high alumina codoping, it makes Tm/Yb co-doped silica fibers promising for applications in fiber lasers and amplifiers.
Tomographic reconstruction of the geometry and refractive index profile of preforms for special fibers
Slánička, Jiří ; Peterka, Pavel ; Matějec, Vlastimil ; Kašík, Ivan ; Pospíšilová, Marie
Tomographic calculation of the refractive index profile of non-circular symmetric optical fibre performs is shown on preform for double clad pumping fibre lasers and amplifiers.
Chromatic dispersion measurement of optical fibres using interferometric technique
Dymák, Pavel ; Peterka, Pavel
Research report deals with measurement of chromatic dispersion of singlemode optical fibres using interferometric technique at IREE AS CR in Prague. The document describes in details all components of measurement setup, initial setting up and measurement procedure, using of assembled control programs and the measurement data processing too. Several tips and practical recommendations complete the report based on many performed experiments.
Optimal fibre cross section shape for cladding-pumped fibre lasers and amplifiers
Peterka, Pavel ; Kašík, Ivan ; Matějec, Vlastimil
The efficiency of the cladding-pumped fibre amplifier critically depends on the coupling of the pump radiation from the inner cladding to the single mode signal core, doped with rare earth ions /Er, Yb, .../. This coupling depends on the cross sectional shape of the inner cladding. In the paper, the conditions of the optimal shape are defined. Verification of these conditions in case of several specific examples, including experimental fibre prepared in the author's laboratory, is shown.
Chromatic dispersion measurement of erbium-doped optical fibres using interferometric technique
Dymák, Pavel ; Peterka, Pavel
Chromatic dispersion measurement on short lengths of erbium-doped optical fibres by the interferometric technique is presented. The resonant dispersion induced by Er3+ ion is calculated from the experimental absortion and emission cross sections.

National Repository of Grey Literature : 16 records found   1 - 10next  jump to record:
See also: similar author names
14 PETERKA, Pavel
Interested in being notified about new results for this query?
Subscribe to the RSS feed.