Two-frequency correlation of photon echo signals in a medium excited by a few-cycle pulses

Two-frequency correlation between the profiles of signals of the primary and long-lived (stimulated) photon echos in a three-level medium excited by combined sequences of resonance quasimonochromatic (encoding) signals and femtosecond pulses consisting of a few optical oscillations (down to one) is predicted. It is shown that the profiles of echo responses of both frequencies correlate with each other and with the profiles of encoding pulses, copy them, and induce mirror rotations, as well as scaling transformations in time in dependence on the methods of forming exciting sequences.