  Coherent responses of resonance atom layer to short optical pulse excitation
are numerically considered. The inhomogeneous broadening of one-photon
transition, the local field effect, and the substrate dispersion are involved
into analysis. For a certain intensity of incident pulses a strong coherent
interaction in the form of sharp spikes of superradiation is observed in
transmitted radiation. The Lorentz field correction and the substrate
dispersion weaken the effect, providing additional spectral shifts. Specific
features of photon echo in the form of multiple responses to a double or triple
pulse excitation is discussed.
