Phase control of photon-echo dynamics with overlapping pulse pairs

We report on the dynamics of two-pulse photon echoes in a two-level system. We consider two different types of excitation pulse pairs: pulses with the same carrier envelope phases (CEP pulse pairs) and pulse pairs cut from the same carrier wave train (labeled as normal pulse pairs). We show that for CEP pulse pairs when the pulses overlap somewhat the photon-echo emission time is strongly sensitive to the relative phase (i.e., delay time) between the two pulses. We also show how the photon-echo emission time for such CEP pulse pairs depends on the dephasing time of the polarization (T_2) and the pulse width of the applied pulses. This phase sensitivity can be utilized to control the emission time of the photon echo which may prove useful in storing and retrieving light signals from an atomic ensemble. Our results also inform the interpretation of photon-echo signals at short delay time when used to measure fast coherence decay rates.