Photonic Crystal Waveguide Output Energy Distribution And Subwavelength Metal Grating Slit Width Effect

This thesis consists of two parts dealing with respectively the tow active directions in optical physics. One is about the energy distributions of the light shooting out from the photonic crystal wave guide, and the other one is about the extraordinary optical transmission.In the first part, the energy distributions in space from photonic crystal waveguide (PCW) are calculated using plane wave expansion method and super cell technique. The results show that the wider field distribution on the exit of the PCW leads to the light radiating farther in space, and the wider line defect is also in favor of the farther transmission of light in space.The second part studies the extraordinary optical transmission of thin metallic gratings by use of the Finite Difference Time-Domain method. We calculated the dependence of the transmissivity of the metallic grating on the slit width and the thickness of the thin metallic film. The following results are found: there is an optimum slit width that corresponding to the maximum single-slit effect. In this case the inter-slits coupling almost disappears. This result may be see as a validation of our earlier calculation; when each slit of the grating becomes wide enough the transmission of light trends to the case of classical optics, and in this case both the single-slit effect and inter-slit coupling vanish; between the optimum slit width and the large slit width, there exists a slit width that makes the grating display the largest inter-slit coupling effect; the transmissivity varies periodically with the film thickness.