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Strong coupling in plasmonic antennas
Beneš, Adam ; Křápek, Vlastimil (referee) ; Kejík, Lukáš (advisor)
Localized surface plasmons generated by ilumination of metallic nanostructures focuses light into nanoscale regions where it can interacts with other nanoobjects nearby. This bachelor's thesis focuses on fabrication of plasmonic antennas suitable for strong coupling with non-conductive or semiconductor nanostructures such as dye molecules or quantum dots in visible range. At first we put forward some theoretical background and summary of strong coupling systems. In the main section we describe process of fabrication and characterization of plasmonics antennas as well as deposition methods for emitors. Lastly, we study interactions in our systems using spectroscopic measurements and strong coupling is realized using FDTD simulations.
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Numerical optimization of absorption of mid-infrared plasmonic structures
Kulič, Martin ; Křápek, Vlastimil (referee) ; Kvapil, Michal (advisor)
Plasmonic nanostructures have a long and rich history in spectroscopy and sensing. First, we look at the history and applications of plasmonic structures and we discuss the parameters that influence the enhancement of various methods. Then the influence of plasmonic nanostructures on energy absorption in a thin layer of silicon oxide, silicon nitride and silicon-rich oxynitride of varying thickness is probed using Lumerical FDTD Solutions software. The last part of this thesis focuses on numerical demonstration of application of plasmonic antennas in spectroscopy.
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Strong Coupling in Plasmonic Structurers
Gryga, Michal ; Brzobohatý, Oto (referee) ; Šikola, Tomáš (advisor)
This diploma thesis deals with numerical simulations of the optical response of plasmonic infrared antennas placed on silicon substrates with thin film of silicon dioxide and subsequently with fitting of scattering spectra by model of coupled harmonic oscillators. In this work, we study an influence of length of antennas on the strength of coupling of localized surface plasmons in the antennas with phonons in silicon dioxide film. Also, the influence of silicon dioxide film thickness on this coupling is investigated.
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Fabrication and characterisation of plasmonic antennas on selected thin film with aim to get enhanced absorption due to presence of strong coupling
Vodička, Martin ; Kepič, Peter (referee) ; Liška, Jiří (advisor)
Strong coupling systems offer many important applications in various fields such as photonics, chemistry, nonlinear optics and others. This Bachelor's thesis focuses on the fabrication of metal plasmonic structures suitable for the formation of strong coupling between localized surface plasmon antennas and hexagonal boron nitride (hBN) thin film phonons in the infrared region. In the case of inducing a strong coupling, an increase in absorption should occur, which makes it possible to use this system to fabricate an infrared detector, the so-called microbolometer. The thesis summarizes important findings from electromagnetic field theory, describes the formation of strong coupling from the perspective of classical physics and gives examples of systems with strong coupling. Furthermore, the formation of surface plasmon polaritons and localized surface plasmons (LSPs) is theoretically described. Plasmonic antennas, their fabrication, applications and physical properties of hBN are described. In the practical part of the thesis, fabrication of plasmonic antennas under or on hBN thin film has been realized. The fabricated samples were characterized by scanning electron microscopy and the spectral response was measured by Fourier transform infrared spectroscopy. In the spectra, the absorption of hBN at 7.3 m was confirmed and additional transmittance minima corresponding to the presence of antennas were detected. The presence of a strong coupling between the LSPs antennas and the phonons of the native SiO2 layer was probably observed. Whether there was a strong coupling between the LSPs antennas and the hBN phonons cannot be inferred from the the obtained results.
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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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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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Optical response of infrared plasmonic antennas in presence of silicon dioxide thin film
Biolek, Vladimír ; Dubroka, Adam (referee) ; Kvapil, Michal (advisor)
The diploma thesis deals with the optical response of resonant infrared antennas on silicon dioxide thin film. At first, theory of electromagnetism at metal/dielectric interfaces is described. In the next part, experimental and numerical methods used in the thesis are described and strong coupling between two systems is explained. In the final part of the thesis, the optical response of resonant infrared antennas on a silicon dioxide thin film is studied by Fourier transform Infrared Spectroscopy and FDTD simulations which both show the strong coupling between localized plasmons and phonons in silicon dioxide.
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Fabrication and characterisation of plasmonic antennas on selected thin film with aim to get enhanced absorption due to presence of strong coupling
Vodička, Martin ; Kepič, Peter (referee) ; Liška, Jiří (advisor)
Strong coupling systems offer many important applications in various fields such as photonics, chemistry, nonlinear optics and others. This Bachelor's thesis focuses on the fabrication of metal plasmonic structures suitable for the formation of strong coupling between localized surface plasmon antennas and hexagonal boron nitride (hBN) thin film phonons in the infrared region. In the case of inducing a strong coupling, an increase in absorption should occur, which makes it possible to use this system to fabricate an infrared detector, the so-called microbolometer. The thesis summarizes important findings from electromagnetic field theory, describes the formation of strong coupling from the perspective of classical physics and gives examples of systems with strong coupling. Furthermore, the formation of surface plasmon polaritons and localized surface plasmons (LSPs) is theoretically described. Plasmonic antennas, their fabrication, applications and physical properties of hBN are described. In the practical part of the thesis, fabrication of plasmonic antennas under or on hBN thin film has been realized. The fabricated samples were characterized by scanning electron microscopy and the spectral response was measured by Fourier transform infrared spectroscopy. In the spectra, the absorption of hBN at 7.3 m was confirmed and additional transmittance minima corresponding to the presence of antennas were detected. The presence of a strong coupling between the LSPs antennas and the phonons of the native SiO2 layer was probably observed. Whether there was a strong coupling between the LSPs antennas and the hBN phonons cannot be inferred from the the obtained results.
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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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Numerical optimization of absorption of mid-infrared plasmonic structures
Kulič, Martin ; Křápek, Vlastimil (referee) ; Kvapil, Michal (advisor)
Plasmonic nanostructures have a long and rich history in spectroscopy and sensing. First, we look at the history and applications of plasmonic structures and we discuss the parameters that influence the enhancement of various methods. Then the influence of plasmonic nanostructures on energy absorption in a thin layer of silicon oxide, silicon nitride and silicon-rich oxynitride of varying thickness is probed using Lumerical FDTD Solutions software. The last part of this thesis focuses on numerical demonstration of application of plasmonic antennas in spectroscopy.
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