| Abstract [eng] |
Light to matter interaction enhancement as well as light propagation control can be realized via guided mode resonance filters, which are thin films deposited on transparent Fused Silica gratings via Ion Beam Sputtering method. Guided mode resonance phenomenon is explored during the preparation of this thesis via analytical, numerical and experimental means. The thesis heavily incorporates numerical simulation of physical phenomena related to guided modes in the corrugated structures, whose resonant properties vary from low to high qualities. The former low quality resonances can be used to achieve broadband spectral reflection for a single, transverse electric, polarization, but has its angular response limited due to Rayleigh anomaly - critical wavelengths that provide additional diffraction orders. Such effect is realized via single layered waveguide, which can replace multilayer Bragg gratings in laser resonator systems. Furthermore, single layer periodically modulated thin films near Rayleigh anomaly pertain asymmetrical-like spectral responses due to the photonic states being localized near the cut-off region where the electromagnetic field is freely propagating. Such resonances are expected to have a narrow-band spectral response, which is particularly useful for spectral filtering and also as polarizers. Furthermore, asymmetrical placement of absorbing materials on such structures enforce unidirectional guided mode propagation, which is enabled via non-hermitian coupling between incident light and propagating guided modes. The main consequence is increased absorption of the structure, which is the most intense near Rayleigh anomaly. Such phenomenon can be applied for novel light absorbing elements, such as solar cells. Furthermore, if the thin film has optical amplification, high quality resonance can be tuned to enhance the fluorescent signal, which follows the resonant pattern in angular and wavelength range, given the fact that the resonance is able to modify peak fluorescence of the active material by a factor of nanometers. In turn, the angular response of the GMR is narrow in this case and such devices can be applied in micro-lasing systems, amplifiers and active polarizing spatial filters. |
