Highly efficient peculiar optical phenomena provided by low symmetric photonic crystal structures

The control of the light in the medium is shaped based on the effect of the functions corresponding on the wave vector. The propagation of light entering the structure in an appropriate way depends on a periodic function that is caused by differences in the dielectric coefficient. Periodicity provides an opportunity for basic optical behaviors such as scattering, reflection, or deflection, which tend to be predominant during light propagation. In this thesis, low symmetric configurations that inside the photonic crystal causes dielectric divergence, hence various light phenomena are observed. In the first study of the thesis, a structure that allows the light to show its self-collimation property during the propagation has been discussed, and the tendency of the light to proceed from the examined equi-frequency curves has been estimated. In order to be sure of the behavior of the light expected to be scattered in the structure, the group velocity distribution and the third order dispersion graphs are examined and with the help of time electric field and transmission analysis, it is ensured that the targeted self-collimation behavior can be obtained for the designed structure. Thus, it has been shown that the designed structure can protect the self collimating ability of the structure over a wide operating frequency range without encountering coupling problems even at very high entrance angles. These results were also fixed by microwave experiment. The second study of the thesis focuses on a super-prism structure with a wide wavelength operating area which shows a combination of high deflection, high wavelength sensitivity and self-collimation in the structure. For the unit cells with equal filling ratios, the frequency diagrams, group velocity distributions and third order distributions for the configuration in which the super-prism effect is observed are analyzed. Accordingly, it is observed that the light will show different deflections to different input angles and wavelengths. According to later finite difference time domain analyses, it was seen that the structure affected the light as expected and carried it with high transmissions. Microwave experiments are also conducted to provide the properties studied. In the third study of the thesis, a cavity structure with high-quality factor and frequency adjustability is mentioned. In the first stage, the band diagrams are focused on the modes that occur in the defect region created by the structural modification of the used dielectric materials. Subsequently, electrical field measurements were made in parallel with the transmission measurements and mod profiles were investigated. For specified modes, wavelength sensitivity, quality factor, Purcell factor and mode volume analysis are applied. For the mode that gives the best results, two- and three-dimensional simulations have been evaluated. In addition to the simulations, microwave experiment measurements were made, and simulation-experiment consistency was observed. In the fourth study of the thesis, the slow light phenomenon in the design of the photonic crystal in the quasi structure was investigated by means of electric field measurements and transmission graphs. The slow light performance was evaluated by the numerical results of the group index and time delay characteristics according to distance.According to the conclusions that overlap microwave experiments, the results show slowing of the light with the help of the quasi-crystal structure.