The interaction of electromagnetic E-waves with one-dimensional photonic crystals consisting of weak conductive and transparent layers is studied theoretically. If the thicknesses of both the conductive and transparent layers are of the order of skin depth, then the domains of transmission and reflection appear. However, if the thickness of the conductive layers is much less than the skin depth but much more than the Debye screening radius, the resonant behavior of the optical power coefficients appears at a frequency close to the plasma frequency.

The longitudinal plasmons in the plasma of conductivity electrons between the surfaces of a thin flat conductive film are investigated. It is shown that these plasmons lead to a resonant behaviour of the optical power coefficient of E-wave interaction with this film. The conditions for appearance of these plasmon resonances are found, and peculiarities of the dependence of the resonant frequencies on the film characteristics are revealed.