Transmission spectrum and defect mode of symmetric one-dimensional photonic crystal

We investigate transmission spectrum and defect mode position of three symmetric one-dimensional photonic crystal samples A(air/[PbTe/ZnSe] m /[ZnSe/PbTe] n /galss), B(air/[ZnSe/PbTe] m /[PbTe/ZnSe] n /glass) and C(air/PbTe/ZnSe/PbTe] m /[PbTe/ZnSe] m /PbTe/glass) by transfer matrix method. It is found that under a given center wavelength of forbidden band, the defect mode position of sample A, B and C will not change with the number of growth period m and n, but the transmittance of defect mode depends on values of m and n. When m equal to n, that is a completely centrosymmetric structure, the maximum transmittance of defect mode is obtained. Under the same values of m and n, the spectral properties of sample A is better than sample B; with smaller values of m and n, sample C can obtain the same good spectral properties as sample A. In addition, symmetric structure photonic crystal can avoid mode splitting and shift, and can further simplify the preparation process. It is believed that the results given in our paper are of guiding significance for the preparation of one-dimensional photonic crystals to obtain a "hole-digging" spectrum at specific wavelength in order to achieve compatible infrared and laser stealth.