Long-Lived Modified Stimulated Photon Echo 1. Atoms with Zero Nucleus Spin

We predicted the possibility of formation of the long-lived modified stimulated photon echo (LMSP echo) and found the intensity and polarization of the LMSP echo signal produced by atoms with zero nucleus spin. It was shown that the experimental studies of the decrease in electric field components of the LMSP echo signals as a function of the time delay between second and third exciting pulses provides relaxation times for orientation and alignment of resonant atoms in the ground state. The conditions were found at which the LMSP echo signals can restore the information recorded in the temporal shape of the first or second exciting pulses, with the information being simultaneously squeezed or stretched in time. We propose some experiments for verification of the theory.