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Plasmonically active nanostructures for optical filtering
Idesová, Beáta ; Liška, Jiří (referee) ; Rovenská, Katarína (advisor)
This bachelor’s thesis deals with optical color filters composed of plasmonically active nanostructures and studies the parameters which influence the performance of such filters. Using electron beam litography and selective reactive ion etching, plasmonic hole-like filters were prepared in alumina film on fused silica substrate. The fabricated arrays of nanostructures, acting as optical filters, varied in shape and size of the nanostructures, distances among the nanostructures and their lateral arrangement within the arrays. The influence of these factors on transmission spectra of plasmonic filters was experimentally analysed using optical spectroscopy. A majority of the observed alternations of the measured transmission spectra was consistent with the research study which is, as well, part of this thesis. The highest color filtering selectivity was observed in arrays with divided square structure shape which also exhibited decent transmittance.
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Automatization of experimental setup for optical spectroscopy
Čecháček, Jan ; Nováček, Zdeněk (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with the modernization and improvement of an application that automates measurements on an experimental setup for spectral and topographic mapping using confocal microscopy and near-field microscopy. The arrangement of the report, the principle of communication of the program with individual parts of the report and the principle of data collection and processing are described here. The output of the program are point spectra and 2D maps describing the topography, intensity and position of the spectral peaks. The thesis includes a research study of optical and time-resolving optical spectroscopy and their applications in nanophotonics. The correct functionality of the program is demonstrated by the results of measurements of perovskite MAPbI3 and organic substrate.
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Automatisation of an experimental setup for optical spectroscopy
Hrabina, Jakub ; Gallina, Pavel (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with the development and description of an application that enabled full automation of an experimental assembly for spectral mapping using confocal optical microscopy. It presents communication with all individual devices and explains the principle of data collection from the examined sample and their subsequent mathematical processing. The output of this application is the visualization of 2D spectral maps evaluating the intensity and position of spectral peaks, with the possibility of exporting user-friendly point spectra. In addition, the work further describes a research study of optical confocal spectroscopy with applications to nanophotonics. In addition, the functionality of the whole application is demonstrated on the spectral response of a 2D metasurface, which acts as a Bayer mask.
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Measurement of extinction spectra of optically trapped plasmon nano-particles
Flajšmanová, Jana ; Jonáš,, Alexander (referee) ; Brzobohatý, Oto (advisor)
This thesis deals with the dark-field imaging and the optical spectroscopy of optically trapped plasmonic nanoparticles. The optical trapping and the characterization of a single particle or multiple nanoparticles as well are demonstrated. The number of the optically trapped particles can be estimated from the dark-field scattering intensity. Experiments show the presence of the interparticle coupling among trapped metallic nanoparticles which has not been observed in case of dielectric particles. The scattering spectra of the plasmonic nanoparticles were compared with theoretical models based on the Mie theory and the Discrete dipole approximation.
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Automatization of experimental setup for optical spectroscopy
Čecháček, Jan ; Nováček, Zdeněk (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with the modernization and improvement of an application that automates measurements on an experimental setup for spectral and topographic mapping using confocal microscopy and near-field microscopy. The arrangement of the report, the principle of communication of the program with individual parts of the report and the principle of data collection and processing are described here. The output of the program are point spectra and 2D maps describing the topography, intensity and position of the spectral peaks. The thesis includes a research study of optical and time-resolving optical spectroscopy and their applications in nanophotonics. The correct functionality of the program is demonstrated by the results of measurements of perovskite MAPbI3 and organic substrate.
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Optical spectroscopy of magnetic semiconductors suitable for spintronic applications
Saidl, Vít ; Němec, Petr (advisor) ; Mics, Zoltán (referee)
In this work we investigate optical properties of new antiferromagnetic semiconductor - LiMnAs. This semiconductor oxidizes easily in air. This fact complicates significantly the investigation of its properties by the optical spectroscopy. This problem was solved by a construction of the optical setup that enables measurements of the reflectivity spectra directly in the chamber where this semiconductor is prepared by a molecular beam epitaxy (MBE). Firstly, the reliability of this optical setup was tested by the measurements of the reflectivity spectra of the well known semiconductors (GaAs and InAs). Secondly, the first measurements of LiMnAs reflectivity directly in the MBE chamber was performed.
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Interaction of short-wavelength laser pulses with matter on various time scales
Vozda, Vojtěch ; Kunc, Jan (advisor) ; Caha, Ondřej (referee) ; Timneanu, Nicusor (referee)
An advent of powerful sources producing intense and ultrashort laser pulses containing high-energy photons opened up a wide range of possibilities to conduct experiments formerly achievable only through theoretical calculations and models. This thesis provides a complex overview of processes which occur right after arrival of the first photons, through lattice heating, up to resolidification and formation of irreversible changes. Irradiated spots and craters formed in various materials are examined employing a wide range of microscopic and spectroscopic methods which provide a deep insight into laser-induced modifications such as detachment of a graphene layer from SiC substrate or thermally-induced diffusion of tellurium inclusions through CdTe lattice. An increased emphasis is placed on beam characterization utilizing ablation and desorption imprints in suitable solids. A proper knowledge of the beam fluence profile may serve for evaluation of diverse damage thresholds as well as for modelling of the pulse propagation or consequent retrieval of otherwise unmeasurable opacity of warm dense aluminium plasma heated to temperatures exceeding tens of thousands of Kelvins. Moreover, the method of desorption imprints is extended to accurate characterization of pulses delivered at MHz repetition rate....
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Automatisation of an experimental setup for optical spectroscopy
Hrabina, Jakub ; Gallina, Pavel (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with the development and description of an application that enabled full automation of an experimental assembly for spectral mapping using confocal optical microscopy. It presents communication with all individual devices and explains the principle of data collection from the examined sample and their subsequent mathematical processing. The output of this application is the visualization of 2D spectral maps evaluating the intensity and position of spectral peaks, with the possibility of exporting user-friendly point spectra. In addition, the work further describes a research study of optical confocal spectroscopy with applications to nanophotonics. In addition, the functionality of the whole application is demonstrated on the spectral response of a 2D metasurface, which acts as a Bayer mask.
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Plasmonically active nanostructures for optical filtering
Idesová, Beáta ; Liška, Jiří (referee) ; Rovenská, Katarína (advisor)
This bachelor’s thesis deals with optical color filters composed of plasmonically active nanostructures and studies the parameters which influence the performance of such filters. Using electron beam litography and selective reactive ion etching, plasmonic hole-like filters were prepared in alumina film on fused silica substrate. The fabricated arrays of nanostructures, acting as optical filters, varied in shape and size of the nanostructures, distances among the nanostructures and their lateral arrangement within the arrays. The influence of these factors on transmission spectra of plasmonic filters was experimentally analysed using optical spectroscopy. A majority of the observed alternations of the measured transmission spectra was consistent with the research study which is, as well, part of this thesis. The highest color filtering selectivity was observed in arrays with divided square structure shape which also exhibited decent transmittance.
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