Properties of mirror symmetrical 1-D photonic crystals with an imaginary part of dielectric constant defect

By means of optical transfer maxtrix,the band function and the optical transmission properties of mirror symmetrical photonic crystals with an imaginary part of dielectric constant defect were studied,especially in the case of negation imaginary part and the λ0/2 optical thickness of the defect.The investigation results show that a large transmittance gain appears at the photonic band edges if an imaginary part of dielectric constant defect is added in the photonic crystals.With the increasing of the imaginary and the real part of defect's dielectric constant,the transmittance gain is increasing firstly then decreasing and in the middle the transmittance gain apex appears.However,the place and altitude of the defect film are invariable.The conclusion is useful for narrow band filter and optical amplification device synchronously.