Photonic crystals built on contrast in attenuation in an immersion medium

Optical properties have been studied for a one-dimensional photonic crystal, where the contrast between the impedances of layers is achieved due to the difference not in the real parts but in the imaginary parts of their permittivities. The spectral dependences of the transmission, reflection, and absorption coefficients of a finite-thickness slab of the crystal have been calculated for the case where it is placed in an immersion medium with the same magnitude of the real part of the permittivity as in layers of the photonic crystal. It has been demonstrated that, although these structures do not form band gaps, there are indications (traces) of the gaps and the optical properties in these regions can differ strongly from those in the homogenized case.