Properties of defect modes in one-dimensional ternary photonic crystal

We have studied the properties of defect modes in one-dimensional ternary photonic crystal with one defect layer using transfer matrix method(TMM). we first compared the transmission spectra of one dimensional ternary photonic crystal with that of one dimensional binary photonic crystal, and found more bandgaps in the ternary structures. Then we are interested in the defect mode properties of the ternary structures, especially the optical sensing abilities. In the special bandgap owned only by the ternary photonic crystals, the defect modes are found to be very sensitive for sensing very small refractive index changes or very small thickness modulations of the defect layer medium. The defect mode wavelength could shift by 3nm for each refractive index change of 0.006, and the defect mode wavelength could shift by 13nm for each thickness change of 10nm. Finally we introduced a negative-refractive-index defect layer into the ternary structure and found that the defect mode wavelength could shift even by 27nm(two times of 13nm) for each thickness change of 10nm.