Hlavní stránka > Výsledky hledání: keywords:"nanoanténa"
Hledej:
Tipy pro vyhledávaní :: Rozšířené hledání
Hledej ve sbírkách:
Seřadit podle: Zobrazit výsledky: Výstupní formát:
Národní úložiště šedé literatury Nalezeno 2 záznamů.  Hledání trvalo 0.01 vteřin. 
Dichroism in electron energy-loss spectroscopy
 Ošmera, Martin ; Lourenço-Martins, Hugo (oponent) ; Konečná, Andrea (vedoucí práce)
Vortex electron beams (VEBs) are a class of chiral free electron states carrying orbital angular momentum (OAM). Right-handed and left-handed VEBs, acting as probes, can interact differently with chiral objects, yielding measurably different results in electron energy-loss spectroscopy (EELS) experiments. This nontrivial behavior is usually referred to as dichroism. In this theoretical thesis, we considered two different (chiral) samples. First, we reviewed the theory of phonon excitation in 2D hexagonal crystals and studied the possibility of the prediction of vibrational-EEL signal. We then followed with a theoretical model of localized surface plasmon excitation on a prototype of a chiral plasmonic nanoantena -- single-twist helix. We proposed an experiment, in which the EEL spectrum is resolved in pre-interaction and post-interaction OAM. We treated this problem both analytically and numerically and showed conditions necessary for the emergence of dichroism, as well as the possibility of optimizing the experimental parameters for maximization of the dichroism.
Úplný záznam
Enhanced spectroscopy with photons and electrons
 Kabát, Jiří ; Neuman, Tomáš (oponent) ; Konečná, Andrea (vedoucí práce)
One of the main applications of infrared spectroscopy is analysis of the composition and chemical properties of molecular samples. However, the far-field infrared spectroscopy techniques often suffer to detect small amounts of molecules. One of the ways to overcome the low signal of minute molecular amounts is by introducing the influence of a strong near field. In this thesis, we theoretically study the enhanced infrared spectroscopy with photon and electron probes. First, we review the theoretical background, with a focus on electrodynamics and nanophotonics. Then we show the results of numerical and analytical calculations for the optical cross sections and the electron energy loss spectra for nano-antennas. The main part of this thesis deals with semi-analytical modeling of the antenna-molecules system, where we compare the results of molecular signatures in the spectra from the model with the numerical simulations. Last, we establish figures of merit for designing nano-antenna with the best performance in enhanced spectroscopy for the considered system and signal detection.
Úplný záznam

Chcete být upozorněni, pokud se objeví nové záznamy odpovídající tomuto dotazu?
Přihlásit se k odběru RSS.
Digitální repozitář :: Hledej :: Nový záznam :: Personalizace :: Nápověda
Powered by Invenio v1.1.2
Spravuje admin.invenio@techlib.cz
Tato stránka je dostupná také v následujících jazycích:
Česky  English