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Excitation and Detection of Plasmon Polaritons
Šustr, Libor ; Schmidt, Eduard (referee) ; Kalousek, Radek (advisor)
The diploma thesis is aimed to excitation and detection of surface plasmon polaritons by visible light. First of all, we will briefly remind some basic principles like waves, electromagnetic wave, light on the interface and optical properties of metals. By using these principles we show presence of surface plasmon polaritons states. After the explanation of their properties there will be clearly visible reasons for aplications of the special excitationand detection methods. We will describe especially the prism coupling, periodic grating coupling and SNOM. Two last sections deal with computer simulations and experiments related to these methods. This means we can exemplify some knowledge presented in previous chapters. Results of simulations are compared with the experiment where we study the excitations of surface plasmon polaritons by periodic grating on aluminium surface.
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Application of metal and semiconductor nanostructures for biodetection
Kejík, Lukáš ; Skládal, Petr (referee) ; Kolíbal, Miroslav (advisor)
The master’s thesis deals with two applications of gold discoidal nanostructures exhibiting plasmon resonance for biodetection. The first approach considers the detection of changes in the phase on plasmonic antennas using coherence-controlled holography microscope. It was found that the steepness of the phase is increasing with the illumination wavelength when plasmon resonance is excited in larger antennas. The sensitivity of the phase to refractive-index changes of the surrounding media was observed when the largest response was given by antennas in resonance with wavelength of illumination. Next part deals with plasmon resonance detection by means of optical spectroscopy combined with voltametry which characterizes the electrochemical activity. Changes in resonance wavelength induced by the presence of SSC buffer were observed, although this influence seems to diminish in time. Conducted experiments have also shown that oxygen-plasma cleaning is not suitable for sample surface cleaning because of oxidation of metals including gold as well.
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Localized Surface Plasmons: Principles and Application
Kvapil, Michal ; Schmidt, Eduard (referee) ; Šikola, Tomáš (advisor)
The diploma thesis deals with plasmonic nanostructures for visible eventually near-infrared region of electromagnetic spectrum. At first, there are discussed basic terms which are necessary for description of plasmonic nanostructures and their properties. Then the resonant properties of gold nanoantennas on a fused silica substrate and in proximity of nanocrystalline diamond are addressed. FDTD simulations are used for an assesment of resonant properties and local electric field enhancement of these nanostructures. Possible manufacturing methods of the antennas and techniques for the measurement of their properties are mentioned at the end of the thesis.
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SNOM probes with special properties
Slabý, Vít ; Kalousek, Radek (referee) ; Spousta, Jiří (advisor)
This bachelor thesis deals with scanning near-field optical microscopy. With SNOM we examined experimentally the near field of the interference of surface plasmon polaritons (PPP) on plasmonic structures consisting of slits in a metal layer a we discuss the effect of probe characteristics on the measurement results.Effect of few characteristics is simulated numerically. Findings obtained in the previous experiments are used for the construction designing of an experimental device called NanoGIS, which should serve for the nanostructure manufacturing.
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Fabrication and testing of microbolometer or other infrared detector based on plasmonic antennas
Děcký, Marek ; Gallina, Pavel (referee) ; Liška, Jiří (advisor)
This bachelor’s thesis is focused on study and fabrication of infrared detectors. Other than just providing a literature research and plasmonics research into the topic, the main goal of this thesis is to propose new designs, manufacturing and characterization such detectors. Specifically the uncooled microbolometer that uses plasmonic antennas for the amplification of the strong coupling which forms between the localized surface plasmons of golden antennas and a phonons of thin dielectric film made from silicon dioxide. The preparation of several types of microbolometers on silicon substrates was conducted using electron beam lithography, photolithography and by thin film deposition techniques. The individual microbolometers differed mainly in the width of the layers between the temperature sensitive meanders and the antennas, but also in the dimensions of the antennas. In the first two sets of microbolometers, the meanders were made from titanium, however meanders in the last set of microbolometers were fabricated from platinum. Reaction of the microbolometers on visible and infrared radiation was tested using measurement of electrical resistance. It was discovered that fabricated microbolometers with titanium meanders significantly reacted on visible light by lowering their resistance. This means they behave like semiconductor. Microbolometers also reacted on infrared radiation by lowering their resistance, but only when temperature of black body source exceeded 400 °C. Reaction on visible and infrared radiation was not observed on microbolometers with platinum meanders with one exception.
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Detection of Localized Surface Plasmons on Metal Nanostructures
Konečná, Andrea ; Dub, Petr (referee) ; Kalousek, Radek (advisor)
This bachelor's thesis deals with theoretical and experimental study of localized surface plasmons excited on metal nanostructures. Analytical calculations were compared to simulations and measurements using assembled apparatus and Fourier-transform infrared spectroscopy (FT-IR) in infrared range. Obtained results were discussed considering both validity of performed approximations and quality of manufactured nanostructures.
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Graphene photodetector based on plasmonic effects
Horáček, Matěj ; Hájková,, Zdenka (referee) ; Šikola, Tomáš (advisor)
Two rich and vibrant fields of investigation - graphene and plasmonics - strongly overlap in this work, giving rise to a novel hybrid photodetection device. The intrinsic photoresponse of graphene is significantly enhanced by placing the gold nanorods exhibiting unique anisotropic localized surface plasmon resonances on the graphene surface. The reported enhanced photoresponse of graphene is caused by the redistribution of localized surface plasmons in the nanoparticles into graphene. The exact underlying energy redistribution mechanism is thoroughly studied by a single particle scattering spectroscopy monitoring the particle plasmon linewidth as a function of the number of underlaying graphene layers. The obtained extraordinary plasmon broadening for nanoparticles placed on graphene suggests the contribution of a novel energy redistribution channel attributed to the injection of hot electrons from gold nanorods into graphene.
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Scanning Near-field Optical Microscopy (SNOM)
Majerová, Irena ; Kvapil, Michal (referee) ; Dvořák, Petr (advisor)
A study of the optical properties of 2D materials has recently been the focus of the broad scientific community for its possible applications in nanophotonics and plasmonics. This bachelor thesis deals with the detection of photoluminiscence (PL) of 2D material (MoS2) by means of near-field scanning optical microscopy (SNOM). This PL is excited in the far-field by means of a focused green laser and in the near-field by surface plasmon polariton (SPP) interference. MoS2 flake monolayers are prepared using micromechanical exfoliation on various functional substrates (metal and dielectric). Characterization and quality of MoS2 monolayers is controlled using Raman optical spectroscopy. Furthermore, the experimentally obtained optical spectra of PL MoS2 are compared in a far-field using confocal optical microscopy and in the near-field using SNOM device, where in the near-field is observed a 3 times higher intensity PL of this 2D material than in the far-field
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Arrays of plasmonic nanostructures made of phase-change materials
Kepič, Peter ; Kejík, Lukáš (referee) ; Ligmajer, Filip (advisor)
Kryštálovú štruktúru materiálov s fázovou premenou dokážeme meniť dodaním vonkajšej energie, čo má za následok zmenu ich elektrických alebo magnetických vlastností. Hoci sa tento efekt ovládania plazmonických rezonancií v nanofotonike využíva, dva materiály zvolené v tejto práci — oxid vanadičitý (VO2) a zliatina železa a ródia (FeRh) — neboli zatiaľ dostatočne preskúmané. Plazmonické rezonancie môžu byť charakterizované ako rezonancie electromagnetického poľa v kovovvých nanoštruktúrach. Týmito nanoštruktúrami sme dokonca schopní ovládať svetlo. Na začiatku tejto práce sa venujeme optimalizovaniu procesu elektrónovej litografie pre výrobu 50nm vysokých kovových nanodiskov s priemermi 40–200nm. V druhej časti skúmame optickú odozvu zlatých nanodiskov, aby sme lepšie pochopili povahu plazmonických rezonancií a interakcií medzi nimi. V poslednej časti sa venujeme optimalizácii výroby polykryštalického VO2 a meraniam optických odoziev VO2 a FeRh nanodiskov počas ich fázovej premeny. Pri meraní VO2 nanodiskov v dielektrickej fázi sme pozorovali Mieho rezonancie. Tieto nanodisky sa majú potenciál chovať ako laditeľné plazmonické štruktúry, ktorých Mieho rezonancie v dielektrickej fázy VO2 sa menia na plazmonické rezonancie v kovovej fázy. Počas merania FeRh nanodiskov sme pozorovali plazmonické rezonancie vo viditeľnom spektre. Tieto rezonancie môžu byť použité na zníženie energie potrebnej na prechod FeRh z anti-feromagnetickej do feromagnetickej fázy.
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Quantum description of superradiance of emitters with plasmon-mediated interaction
Olivíková, Gabriela ; Chvátal, Lukáš (referee) ; Křápek, Vlastimil (advisor)
Superradiance is an enhanced decay of an excited system of emitters resulting from their mutual coupling. This thesis is focused on superradiance of the emitters coupled via their interaction with a plasmonic nanoparticle. So-called plasmon-mediated superradiance results in even stronger enhancement of the decay rate as the nanoparticle serves as an additional decay chanel. We have developed a quantum model of the system of emitters coupled to a plasmonic nanoparticle, which allows us to differentiate between a pure dephasing and decay processes. We show that the pure dephasing can destroy the cooperative effect leading to superradiance. Furthermore, we have studied how the direct mutual coupling between emitters affects time evolution of the system in dependence on its configuration, and we show conditions when a decay of the system is dramatically decreased by direct coupling.
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