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Laser transmitter with fiber
Hašek, Jaroslav ; Němeček, Jiří (referee) ; Wilfert, Otakar (advisor)
This master´s thesis deals with communication which is provided by optical devices. Optical wireless links are enforced due to high bit rate, responsibility and noise immunity. Main part of this master´s project is devoted to optical fibre, its characteristic and its usage in laser transmitter.
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Monochromator
Křivák, Jiří ; Dobesch, Aleš (referee) ; Barcík, Peter (advisor)
This work is focused on analyzing the working principle of monochromator and specifically on HRS-2 Jobin Yvon monochromator with Czerny-Turner optical system. Next, there is described working principle of a diffraction grating, its properties, and design of individual optical system. The suitable wide-spectrum optical source is specified.
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D8 - ADVANCE X-RAY Difractometer Adjustment
Černý, Lukáš ; Šrámek, Miroslav (referee) ; Žák, Roman (advisor)
This graduation thesis deals with Bruker AXS D8 Advance adjustment. Target of this thesis is design and realization of equipment which is going to be applicable on existing D8 advance machine and works with Göbel mirror adjustment. Mentioned adjustment is basic part of service operations necessary for D8. Introduction deals with theory of diffraction and basics of X-ray. Following part is presenting design of model which can be applicable and useful for solving of our problem. This design is completed with function device. This device realization is created by driving mechanism, control unit and mechanical adapter which is flexible and compatible with existing D8 Advance machine. All parts of designed device are fully described and complemented for full technical documentation, which is part of attachments.
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XRD characterization of electrodes and electrode materials for electrochemical power sources
Klvač, Ondřej ; Chladil, Ladislav (referee) ; Čech, Ondřej (advisor)
The thesis describes available choices of methods for research of electrochemical power source electrode strcture by x-ray diffraction spectroscopy. At first there is a theoretical computation of difractogram. Then there are discussed possibilities of in-situ and ex-situ techniques as background research. Practical part of thesis compares theoretical assumptions to measurements of lithium and sodium cells, including analyze of crystallographic phases and lattice constants. As a conclusion, there are discussed possibilities of subsequent research.
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Compensation of loudspeaker measurements using standard baffle
Štěpáník, Jiří ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
The frequency response of the loudspeaker is one of the key data that needs to be known, for example, when designing a speaker cabinet or speaker system. The frequency response should be achieved with the highest possible accuracy and with a minimum of distortion. How to achieve such characteristics is described in the standard ČSN EN 60268-5, which states as one of the ways the use of standard enclosures. Except for the standard baffle, these baffles have correction curves for the measured characteristics described in the standard. However, this does not mean that the standard baffle does not distort the measurement. The aim of this work is to analyze the distortion of measurements caused by this baffle and other elements and their compensation. The work contains a description of certain parts of the standard ČSN EN 60268-5 with focus on the standard baffle. Especially on its construction and methods of measuring the speakers mounted on it. Several test measurements were performed within the work. These measurements were performed in a anechoic chamber with speakers mounted on a modular standard baffle, which is a modification of the standard baffle which is also described in the work. The measurements performed include the measurement of frequency characteristics at different distances of the microphone from the speaker at different positions of the baffle in the anechoic chamber. The test measurements show that the modular standard baffle and anechoic chamber cause measurement distortion. In other measurements, the distortion by the anechoic chamber is minimized and the distortion caused by the base of the modular standard baffle is completely eliminated. The thesis then presents the theory of sound diffraction at the edges of a standard baffle and the theory of the extended Biot-Tolstoy-Medwin method of modeling these diffractions using numerical calculations. Based on this theory, software compensation of diffraction distortion was performed in Matlab. It is not entirely clear from the results of the compensation to what extent it can be considered successful. It can be speculated that it only works on certain frequencies. It is necessary to verify the functionality of this compensation method by another test measurement.
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The adjusting collimator for the Fluorescent holographic microscope
Hlaváčová, Kateřina ; Jákl, Petr (referee) ; Dostál, Zbyněk (advisor)
For the proper function of the Fluorescence olographic microscope, it is necessary to adjust all the optical components of the microscope. Furthermore, the precise adjustment is the very critical condition for proper imaging of the Coherence-controlled holographic microscope. Therefore, it is necessary to create a sight collimator for these microscopes for their adjustment. The fluorescence holographic microscope is based on an interference and holographic principles, whose history is mentioned in the theoretical part of the thesis. The existing state of the art of laser sight collimators and their use in practice is also mentioned. The optical and mechanical design of the laser sight collimator and its realization are described in the next part of the thesis. The software for detecting the black sight cross was created for the use of the laser sight collimator in practice. The software is necessary to evaluate the correctness of the alignment of the adjusted microscope. The descriptions of the adjustment procedures for the laser sight collimator and for the Fluorescence holographic microscope are mentioned in the last part of the thesis. These procedures are necessary for proper manipulation and use with the proposed laser sight collimator.
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Diffraction on Spatial and/or Deep Objects
Hrabec, Aleš ; Petráček, Jiří (referee) ; Kotačka, Libor (advisor)
This discourse deals with a theoretical study of the radiation passage through a diffraction screen with non-zero size in the propagation direction of the radiation, i.e. the radiation passage through a three-dimensional object. Without any loss of generality, we solve the problem for cylindrical cavity in metal. The task exceeds evidently standard scalar theory of diffraction, thus we solve the problem using a waveguiding theory. Following the principles of the electromagnetic theory, we derive required formulae to determine mode distribution at the entry of the cavity. Further, we solve numerically the radiation propagation through the cavity, then we actually seek for radiation distribution at the very end of the cavity. This yields, with a help of the discrete Fourier transform, an intensity distribution of Fraunhofer diffraction pattern, consequently compared with an intesity distribution of the radiation pattern of Fraunhofer diffraction on infinitely thin circular opening having the radius of the cylinder cavity under study. A comparison of such patterns results to a conclusion, that the cavity length has a significatn influence on the diffraction pattern and more importantly, that the scalar diffraction theory appears incorrect for a coherent light passage through cavities longer than their radius squared. Similarly, the same conclusion is inversely proportional to a wavelength of the interacting radiation. Finally, we mention an existence of the so called "focal regime", when the radiation repeatedly exhibits roughly one order increased intensity on the symmetry axis of the cavity.
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Special diffractive element based on fractals
Kala, Miroslav ; Bednář, Josef (referee) ; Kotačka, Libor (advisor)
This diploma project is focused on use the fractals in diffractive optical elements. Properties of diffraction patterns of various fractals are investigated. Properties of some simpler non-fractal structures are investigated too. Diffraction patterns are created by computer with program written in Delphi programming language. Potentialities of use the fractals in security optical elements (holograms) and their advantages against the classic non-fractal structures.
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