Study On Angular And Frequency Selectivity Based On One-Dimensional Photonic Crystal

Photonic crystal (PhC) is the periodical arrays of materials with the different refractive index which can control the lights propagation. PhC has attracted more and more attention due to its outstanding performance in light manipulation. In addition, the wide application of PhC materials in the modern photoelectron industry has stimulated great interests in studying their properties both theoretically and experimentally. In the past decades, tremendous progresses in frequency selectivity have been made by taking advantage of photonic band gap. However, light selection based on the direction of propagation has seen relatively slower progress because of scientific and engineering limitation. So far, only few breakthroughs have been made in broadband angularly selective PhC materials.In this thesis, the angularly selective structures based on one-dimensional PhC, the azimuth-and elevation-angularly selective structure based on asymmetric photonic crystal (APC) and the angle-frequency filter based on cascaded one-dimensional PhC are designed and optimized through theoretical analysis and numerical simulation. The main research works and results are listed as follows:Firstly, a modified broadband angularly selective filter constructed by multiple one-dimensional PhCs, each with a different periodicity, is investigated. This filter enables transparency at the Brewster angle and reflection at every other viewing angle within a broad waveband from 0.2 ?m to ?m under p-polarized illumination. Furthermore, a broadband angular absorber, which works through all-visible spectrum (0.38?0.7?m), is achieved when choosing lossy dielectric to structure the PhCs.Secondly, a directionally selective structure based on the APC is designed and investigated. The structure owns rigorous spatial selectivity that only allows the transmission of the incidence at certain incident plane and angle. Simulation results show that the proposed structure exhibits simultaneous azimuth- and elevation- angular selectivity, i.e., directional selectivity within a broad waveband from 0.38?m to 0.7?m under p-polarized illumination. Furthermore, the elevation-azimuthal selective angles could be adjusted by restructuring the configuration parameters of the APC. The ranges of elevational selective angles and azimuthal selective angles are 23°?65° and 0?85°, respectively.Finally, a proposal of combining angular selectivity with frequency selectivity by virtue of the cascaded one-dimensional photonic crystals is investigated. And the multifunctional angular-frequency filter and omnidirectional reflector is achieved in all-visible spectrum by utilizing this method.