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Plasmonic lightning-rod effect
Řepa, Rostislav ; Konečná, Andrea (referee) ; Křápek, Vlastimil (advisor)
This bachelor thesis deals with an experimental and theoretical research of the plasmonic lightning-rod effect. Electron energy loss spectroscopy has been used to investigate the electromagnetic response of plasmonic antennas and to study the impact of the curvature of their surfaces on the local enhancement of an electromagnetic field. A theoretical background based on interactions of the electromagnetic field and free electrons in metals is provided in the first chapter. Next, experimental and theoretical methods including the fabrication process of plasmonic antennas and inicialization of simulations are introduced. Observed resonances of localised surface plasmons are characterised in the spectral region and their mapping is performed. The calculated loss spectra are compared with the experimental loss spectra and the field enhancemnet due to the curvature of plasmonic antennas is evaluated.
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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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Imaging the magnetic field of plasmonic antennas based on Babinet's principle
Špičáková, Tereza ; Horák, Michal (referee) ; Křápek, Vlastimil (advisor)
This thesis concerns plasmonic antennas and the electromagnetic field of surface plasmon polaritons. In the first chapter we look at the theory of the electromagnetic field and the electromagnetic wave associated with the interface between metals and dielectric materials and we explain Babinet’s principle. In the next part of the thesis we describe the process of fabrication of plasmonic antennas using Kaufman ion source and focused ion beam. We continue wuth the theoretical description of the electron energy loss spectroscopy and the application of this method for characterizing the optical response of these structures. In the last part we introduce the principles of processing the measured data and the conclusions drawen frome this data. Next we will analyze the limits of the validity of Babinet’s principle and using this principle, we will image the magnetic field of the antennas. Finally, we discuss the possibilities of describing this problem with computer simulation.
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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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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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Plasmonic lightning-rod effect
Řepa, Rostislav ; Konečná, Andrea (referee) ; Křápek, Vlastimil (advisor)
This bachelor thesis deals with an experimental and theoretical research of the plasmonic lightning-rod effect. Electron energy loss spectroscopy has been used to investigate the electromagnetic response of plasmonic antennas and to study the impact of the curvature of their surfaces on the local enhancement of an electromagnetic field. A theoretical background based on interactions of the electromagnetic field and free electrons in metals is provided in the first chapter. Next, experimental and theoretical methods including the fabrication process of plasmonic antennas and inicialization of simulations are introduced. Observed resonances of localised surface plasmons are characterised in the spectral region and their mapping is performed. The calculated loss spectra are compared with the experimental loss spectra and the field enhancemnet due to the curvature of plasmonic antennas is evaluated.
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Imaging the magnetic field of plasmonic antennas based on Babinet's principle
Špičáková, Tereza ; Horák, Michal (referee) ; Křápek, Vlastimil (advisor)
This thesis concerns plasmonic antennas and the electromagnetic field of surface plasmon polaritons. In the first chapter we look at the theory of the electromagnetic field and the electromagnetic wave associated with the interface between metals and dielectric materials and we explain Babinet’s principle. In the next part of the thesis we describe the process of fabrication of plasmonic antennas using Kaufman ion source and focused ion beam. We continue wuth the theoretical description of the electron energy loss spectroscopy and the application of this method for characterizing the optical response of these structures. In the last part we introduce the principles of processing the measured data and the conclusions drawen frome this data. Next we will analyze the limits of the validity of Babinet’s principle and using this principle, we will image the magnetic field of the antennas. Finally, we discuss the possibilities of describing this problem with computer simulation.
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