  A double-rephasing photon-echo (DRPE) scheme inherently satisfies
no-population inversion condition for quantum memory applications, while the
resultant absorptive coherence prohibits echo radiation out of the medium. To
solve the absorptive echo problem in the DRPE scheme, a controlled
double-rephasing echo protocol has been presented and discussed for the
collective atom phase control. In the DRPE scheme, however, a typical Gaussian
light can cause imperfect rephasing processes resulting in a partial emission
of photon echoes. Here, the rephasing process of individual ensemble atoms is
thoroughly investigated to discuss the unpermitted echo observations in the
DRPE scheme, where its maximum efficiency is as high as 26% in amplitude.
