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Measurement of the optical intensity distribution at the far field
Vitásek, Jan ; Němeček, Jiří (referee) ; Wilfert, Otakar (advisor)
The topic of this master’s thesis is energy measurement of the optical intensity distribu-tion at the far field. Properties of the optical intensity and the optical power are described. In this thesis solution of wave equation is done. The plane wave, spherical wave and Gaussian beam are described. In this thesis, optical trace of laser beam from transmitter laser diode to receiver PIN photodiode is described. One of the solved problems is diffraction on the lens socket. The basic configuration for diffraction investigation on lens socket was created. There were transmitting laser diode, stop with circular apertures and PIN photodiode used in the experiment. In the other part, thesis deals with measuring and detection of the optical beam. Sorts of photodiodes and their characteristics were analysed.
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Model of the Surface Optical Intensity Distribution in the Beam
Wintr, Aleš ; Hudcová, Lucie (referee) ; Wilfert, Otakar (advisor)
The aim of the thesis is first to describe the light beam spreading through free space and its characteristics. The theoretical part of the thesis developed programs that display models of beams. Given the parameters, theses models depict areal dispersion of optical intensity in the cross-section of beams. More specifically, I developed both a 2-dimensional and 3-dimensional model of beam depiction and a 3-dimensional model with variable angle of rotation of the beam trace. For this purpose I used the software Matlab R2007a. In the experimental part of the thesis I assembled a measurement chain and measured optical intensity of selected optical fibre. The measurement chain included laser Promax Prolite 80, optical source LED Promax Prolite 81, optic power meter Exfo 67A, collimator Thorlabs F810FC-1550 and optical fibres with various characteristics. The measured values were used to plot graphs depicting aerial dispersion of optical intensity and these graphs were compared with the theoretical computer model developed in the theoretical part of the thesis.
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Optical beam intensity profile analysis
Fojtík, Jakub ; Vitásek,, Jan (referee) ; Barcík, Peter (advisor)
This work is focused on the study of the intensity profile of optical beams. In the first part problematics of optical beams from theoretical point of view is discussed, Model of realistically circular symmetric beam in an ideal lossless, stationary, homogeneous and isotropic medium is formed in Matlab®. The next part of the thesis deals with implementation of automatic workplace for measuring intensity profile of optical beams. Within the thesis - PCB desing of photodetector in Eagle®, is discussed. Custom application for controlling the motorized linear stage M – IMS 400 and communication with photodetector in the Microsoft Visual Studio 2010® was created.
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Computer modeling of laser beam
Mittner, Ondřej ; Wilfert, Otakar (referee) ; Raida, Zbyněk (advisor)
This bachelor’s thesis theoretically describes Gaussian beam, its characteristics and its passing through optical elements. The main attention is focused on creating of computer models of Gaussian beam in COMSOL Multiphysics application, detailed description of these models, presentation of achieved results and comparing these results with theoretic presumptions.
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Radiation pattern shaping of the optical transmitter
Csonka, Gábor ; Němeček, Jiří (referee) ; Wilfert, Otakar (advisor)
This work deals with questions of space assembling of several optics beams. There are mentioned the base features and values of space distribution of beam intensity in laser beam. The forms of diffusion of space localized light that is described by beam optics. There is a characterization of Gaussian beam, and diffraction of several beams. There is mentioned a simulation an assembling of two and more beams. It contains model of assembling incoherent beams. The work also includes suggestion of final layout of laser beams, which form optical transmitter with radiating characteristics, resistant to defects evoked by atmosphere.
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Laser beam coherence in turbulent atmosphere
Polanský, David ; Drexler, Petr (referee) ; Hudcová, Lucie (advisor)
In the first part of the thesis discusses the function of the laser design and construction of its class. Here is an explanation of coherence and other properties of laser radiation. Listed below are the possibilities of energy distribution in the laser beam. Described in particular Gaussian beam. The paper explains the phenomena of bending and Young's experiment. The paper examines the influence of atmospheric environment in the transmission of electromagnetic waves, defined as light. Particular attention is devoted to atmospheric turbulence. In the second part are first discussed the possibility of measuring atmospheric turbulence and coherence of laser beam parameters. The following is designed to measure workplace coherence width and coherence length in a turbulent environment. At these workplaces were measured. The results of these measurements are also listed in the job. The following comparison of results with theoretical values.
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Top hat beam in free space optics
Golda, Martin ; Wilfert, Otakar (referee) ; Hudcová, Lucie (advisor)
This thesis describes a way of laser beam shaping of Gaussian profile to Top hat profile and the influence of atmospheric turbulences and attenuation on both these beam profiles. Its aim is to get acquainted oneself with a structure of atmosphere, principle of optical radiation which is used in free space communication and the influence of atmosphere on laser beam. To be successful in creation of beam with Top hat profile is necessary to study the principle of focusing by using the plano-convex lenses and other diffraction elements. This thesis compares the influence of atmospheric turbulences and attenuation between Gauss and Top hat beam results for two different wavelengths.
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Optimal Intensity Distribution in a Laser Beam for FSO Communications
Barcík, Peter ; Capsoni, Carlo (referee) ; Číp, Ondřej (referee) ; Wilfert, Otakar (advisor)
Dizertačná práca je zameraná na štúdium a analýzu rozloženia optickej intenzity v laserovom zväzku v rovine vysielacej (TXA) a prijímacej apertúry (RXA), ktorý podlieha zmenám ako pri šírení voľným priestorom, tak pri šírení atmosférou. Cieľom práce je nájsť optimálne rozloženie optickej intezity v rovine vysielacej apertúry, ktoré bude minimálne ovplyvnené apertúrou vysielača a atmosférickými turbulenciami. Za účelom analýzy šírenia optickej vlny atmosférou bola využitá simulácia založená na metóde Split-Step. Šírenie Flattened Gaussian zväzku bolo analyzované pre režim slabých a stredných turbulencií. Práca sa zaoberá použitím multimódového vlákna s veľkým priemerom jadra ako tvarujúceho elementu a obsahuje návrh refrakčného tvarovača, pomocou ktorého je možno konvertovať Gaussovský zväzok na zväzok s uniformným rozložením optickej intenzity. Nakoniec je pomocou získaných poznatkov zostavený plne fotonický vysielač a prijímač, ktorých použitie spočíva v generovaní a príjmaní optickej koherentnej vlny prenášajúcej presnú fázu.
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The distribution of relative variance of optical intensity in laser beam
Barcík, Peter ; Coufalíková,, Aneta (referee) ; Hudcová, Lucie (advisor)
This master´s thesis provides basic properties and measurement of optical beams. In the first chapter is shown division of light on ray, wave and beam optics. Atmospheric optics and properties associated with propagation of light through the earth's atmosphere is presented in the second chapter. In the third part are shown basic techniques for Gaussian beam shaping. The last chapter deals with measurement of optical beam after propagating through a turbulent medium. In this section is shown distribution of relative variance of optical intensity in Gaussian and Top-Hat beam. There is also measured spatial coherence of laser beam in the turbulent atmospheric transmission media. Finally effect of the beam wander is investigated.
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