Transmission Spectra of One-Dimensional Photonic Crystals with Single Defect in Different Locations

The transmittance spectra of one-dimensional photonic crystals (1-D PCs) with single defect in different location have been calculated. Defined the parameter N as the number of the layers located to the left of the single defect, set 13 as the number of the total layers of the 1-D PCs included the defect, during the course of the number of N increased from 0 to 12, as it upped to 3, there occurred defect band gap in the stop band gap, and when N upped to 12, the defect band gap disappeared; besides, the defect band gap is at frequencies between 0.3000~0.3090, most of them are at the frequencies around 0.3020. In addition, the transmittance has a turning point at the parameter N=7, that is to say, there has an approximate symmetry in transmittance when the parameter N increased from 3 to 11.