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Evaluation of the gamma-ray spectrum transmitted upon alteration in scintillator shading
Zbožínek, Tadeáš ; Jelínek, Michal ; Mikel, Břetislav
This paper deals with determining the properties of optical fibres required for transmitting energy spectra in ionising radiation measurements by scintillation. Specifically, optical fibres that provide the communication link between the scintillator and the photosensitive electronic devices. The primary objective is focused on the basic diameter and numerical aperture values required for efficient transmission of energy spectra. An iris mechanism gradually shaded the scintillator crystal, simulating the optical fibre diameter. The results can be used to calculate the numerical aperture to achieve this goal. This way, we can establish basic properties for further energy spectra measurements with optical fibres.
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SMV-2023-63: Measuring interferometric systems
Mikel, Břetislav
The contract research was focused on the development of multi-axis measuring systems using the most accurate method of measurement based on the principle of laser radiation interference. The basic reference is a laser source with a wavelength of 633 nm. Measuring systems are intended for devices requiring measurement accuracy in the order of nanometers.
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SMV-2023-62: Optical beam head A
Mikel, Břetislav
A feasibility study for the development of the principle, arrangement and verification of an optical head for 637 nm wavelength, which will have an input adapted to the FC/PC fibre connector, with an output laser beam focused at a distance of 400 mm with a width of 6-10 mm, a thickness of max. 60 um and a depth of field of min. 5 mm.
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SMV-2023-61: Measuring systems for lithographers
Mikel, Břetislav
The contract research was focused on the development of multi-axis measuring systems using the most accurate method of measurement based on the principle of laser radiation interference. The basic reference is a laser source with a wavelength of 633 nm. Measuring systems are intended for devices requiring measurement accuracy in the order of nanometers.
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Splicing of special optical fibers
Hlavatý, Václav ; Holík, Milan (referee) ; Mikel, Břetislav (advisor)
The aim of thesis is to design welding processes for special optical fibers. The text describes procedures of modification of the basic welding process for three types of PM fibers. For each fiber type was created specific welding process. All optimized welding processes were tested in terms of reproducibility.
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Hollow Core Photonic Crystal Fibers
Hlavatý, Václav ; Holík, Milan (referee) ; Mikel, Břetislav (advisor)
Aim of the work was to study, design and verify methods of splicing photonic crystal fibers with standard single-mode and multi-mode fibers. The main goal was to make of the fusion splicer Fujikura FSM 100P splicing process. To create splicing process, various splicing methods were tested. Method of the moving position of the arc discharge from the center of splicing fibers and the method with increased gas pressure in the microstructure were mainly tested. Research revealed the incompatibility of splicing process of the different types of fiber splicers. The main results of the work are optimized methods of the splicing HC 1550-2 fiber and SMF 28 fiber.
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Methods of frequency stabilization of semicondutor lasers
Kozelský, Adam ; Stehlík, Jiří (referee) ; Mikel, Břetislav (advisor)
The main aim of the thesis is a frequency stabilization of the DFB semiconductor laser diodes. The temperature stability of the laser diode chip, the stability and the noise of the injection current and the backward reflections are the crucial parameters which affects the frequency stability. These influences are described and the resolution is proposed. The theory of the external methods of the frequency stabilization and the comparison of these methods is presented. One method was choosed and this method was realized for 760 and 1540 nm wavelength laser diodes. In this method was used the frequency stabilization based on the linear absorption to the spectral lines of the gases. The diploma work is closed by the measured results of the frequency stability of the used laser diodes and by the comparison of level of stability achieved by the other methods.
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