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Observations and modeling of classical Be stars
Klement, Robert ; Korčáková, Daniela (advisor) ; Jones, Carol Evelyn (referee) ; Votruba, Viktor (referee)
The brightness and proximity of many classical Be stars makes them perfect laboratories for studying the physics of astrophysical disks. They are also among the most popular targets for optical/IR interferometers, which are able to fully resolve their circumstellar disks, to which much of the recent progress in our understanding of these enigmatic objects is owed. The current consensus is that classical Be stars eject material from the stellar surface into Keplerian orbits, thus forming a disk, whose subsequent evolution is governed by turbulent viscosity, which is the basis of the so-called viscous decretion disk (VDD) model. Among the main results of the present work is arguably the best-constrained model of a particular Be star β CMi. The VDD predictions were confronted also with radio observations, which allowed for the first determination of the physical extent of a Be disk. This result subsequently led to the detection of a binary companion, which is truncating the disk by tidal forces. Extending the sample to include five more targets led to revealing a similar outer disk structure in all of them. The range of explanations includes the most plausible scenario, in which the truncation of Be disks by (unseen) companions is much more common than previously thought.
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Fiber-Coupled Fabry-Pérot Interferometric Sensor: Analysis And Modelling
Skalský, Michal
This paper presents a theoretical analysis of the Fabry-Pérot interferometric sensor utilizingan extrinsic fiber-optic cavity. Its behavior is modelled and simulated for various conditions,showing the key properties of the different sensor’s setups. The simple single-mode sensing tip andthe GRIN collimator are compared. Further, new kind of sensing head is proposed exhibiting aninverse reflectivity and enabling a theoretical resolution less than 1 pm.
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Optical Fiber Infrastructure Protection Demonstration System Using Distributed Optical Sensing
Dejdar, Petr
The paper deals with optical fiber distributed sensing based on Mach-Zehnder interferometryfor infrastructure protection. The system is used in the landscape model, where digging canbe simulated. The developed system measures vibrations close to the optical fiber and evaluates theexceeding of the limit value of the signal deviation, on the basis of which the alarm is triggered.This demonstration model is used to demonstrate the possibility of protecting the optical fiber infrastructurefrom mechanical damage, such as optical cable cuts caused by digging activity. The paperdescribes both the design of the demonstration system and the GUI for setting and evaluating alarms.
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SMV-2020-29: An optical radiation source assembly with an optional coherence length
Lazar, Josef ; Buchta, Zdeněk ; Pikálek, Tomáš
This laser system combining three light sources with various coherence lengths has been developed for advanced interferometry techniques based on Twyman-Green interferometer inspecting complex optical setups with a sequence of reflecting optical surfaces. It introduces a unique concept of reduction of unwanted “dead fringes” generated by multiple reflections. It is introduced into quality control by an optical manufacturing company Meopta-optika and production of a few more is being prepared.
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Fiber guided illumination module
Kropáč, Vlastimil ; Kvasnica, Lukáš (referee) ; Dostál, Zbyněk (advisor)
This diploma thesis describes the design of the illumination system for a Coherence--Controlled Holographic Microscope (CCHM). The theoretical part mentions the history of microscopy, the principle of holography and individual types of interference microscopy. To get closer to the topic, individual light sources and an overview of current illumination systems are mentioned. The diploma thesis also describes the procedure of designing a fiber-optic illumination module for microscopy from optical design through design of construction to the last step, which is assembly and testing of the module.
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Phase imaging below the diffraction limit
Nečesal, Daniel ; Bouchal, Zdeněk (referee) ; Dvořák, Petr (advisor)
Tato diplomová práce se zabývá konstrukcí interferenčních zařízení pro výzkum měření fáze světla na mikro-strukturách a fáze plazmonů na nano-strukturách. V první kapitole je vybudován teoretický základ pro optiku a nano-fotoniku používané v budoucích kapitolách. Následně je popsána interference vln a jejich praktické použití pro prolomení difrakčního limitu pomocí holografie plazmonů. Prvním experimentální sestavou je Machův-Zehnderův holografický mikroskop. Je popsán způsob, jak ho sestavit z běžně dostupných součástek a jak je navržen ovládací software k jeho používání. Následně jsou popsány výsledky naměřené pomocí tohoto zařízení. V poslední kapitole se zaměříme na sestavení holografického SNOM přístroje pro studování plazmonů a jejich interference. Nejdříve popíšeme základní princip a navržení softwaru pro automatizaci měření, pro zrychlení vědeckých postupů. Nakonec předložíme výsledky měření mikroskopu.
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Coherence Controlled Holographic Microscope with the digital optics
Vavřinová, Jana ; Jákl, Petr (referee) ; Dostál, Zbyněk (advisor)
The Digital Micromirror Device (DMD) technology has been developed especially for Digital Light Processing projectors, which allow the image projection. After this succesful implementation, and thanks to the commercial availibility and low initial cost of the DMD chip, a wide range of other applications became possible. Besides, it may be used in microscopy as a spatial light modulator. For example in Coherence-Controlled Holographic Microscope (CCHM) that finds its use especially for imaging and measurement of live-cell dynamic processes. The DMD chip placed in the illumination part of CCHM allows for broadening the application possibilities. Namely it could be different illumination mode experiments or tomographic applications. The master's thesis deals with the optical design of CCHM with digital optics, i. e. DMD chip. The selection of optical elements for CCHM, the experimental verification of the imaging setup and the process of designing the illumination part are described in detail. In the end, the analysis of different designs for illumination setup with the digital optics in object arm is carried out and the results are compared.
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