Increasing of Energy Density and Level of Coherency at Scattering Radiation at Periodically Heterogeneous Medium

It is shown that in a process of radiation scattering in periodic-heterogeneous medium (the crystals, photonic crystals) with small level of heterogeneity there can be excited waves with amplitudes considerably larger amplitudes of falling waves. These waves with the large amplitudes are eigenwaves of a homogeneous layer with dispersion of a periodic-heterogeneous layer. It is shown that the levels of coherence of these waves are much higher than levels of coherence of falling radiation. The simple formulas for definition of coherence matrix components are received. These formulas generalize the well-known Van-Thitterta-Tsernike formulas