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Babinet principle for plasmonic antennas: complementarity and differences
Horák, M. ; Křápek, V. ; Hrtoň, M. ; Metelka, O. ; Šamořil, T. ; Stöger-Pollach, M. ; Paták, Aleš ; Šikola, T.
Plasmonics deals mainly with surface plasmon polaritons (SPP), which are collective oscillations of free electrons at metal-dielectric interfaces connected with the local electromagnetic field. When SPP are spatially restricted to a metallic nanoparticle, we talk about localized surface plasmons (LSP). LSP resonances can be characterized with an excellent spectral and spatial resolution by electron energy loss spectroscopy (EELS) and cathodoluminescence. Both techniques utilize an electron beam that interacts with the metallic nanoparticle and excites the LSP resonances. EELS measures the energy transferred from electrons to the LSP and cathodoluminescence deals with the light which the LSP emit during their decay. Babinet principle, originating in the wave theory of light and analysis of diffraction, relates the optical response of apertures in thin films and their complementary particle analogues. According to the Babinet principle, LSP in complementary particles and apertures have identical resonance energies and their near fields are closely linked: the electric field distribution of a specific in-plane polarization for an aperture corresponds to the magnetic field distribution of a perpendicular polarization for a particle.
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Unidirectional plasmonic antennas
Formanová, Veronika ; Hrtoň, Martin (referee) ; Kvapil, Michal (advisor)
This thesis deals with directional V-shaped plasmonic antennas. In the thesis, an analytical model of antenna emission is proposed. The results of analytical computations are compared with results of numerical simulations in Lumerical FDTD Solutions package. Also, the process of fabrication of such antennas by electron beam lithography and measurement of optical properties using Fourier infrared spectroscopy is described and measured antenna resonant spectra are shown. Finally, there is a proposal of an experiment to prove the emission directivity of fabricated V-shaped antennas.
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Modeling of Surface-Plasmon Propagation in Graphene
Hrtoň, Martin ; Munzar,, Dominik (referee) ; Kalousek, Radek (advisor)
The diploma thesis provides an introduction to electronic and optical properties of graphene, emphasizing thier tunability through the ambipolar field effect. Furthermore, an experiment, which would demonstrate the possible utilization of graphene in active plasmonics, is presented. The author focuses on light scattering simulations involving hybrid plasmonic structures made of noble metals and graphene. The scattering properties of those structures and their dependence on the density of free charge carriers in graphene are investigated. The author concludes that the proposed tuning of the response of a single metallic antenna through the electrostatic doping of graphene proves to be inefficient, and a more elaborate configuration will be required to enhance the effect and achieve the desired control.
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