Specific Kinetics of Decay of the Stimulated Photon Echo in Ruby Enriched Only by Ions of Isotope $^{53}$Cr

The article presents a first-time report about detailed investigation of the kinetics of stimulated photon echo (SPE) decay in ruby, enriched only by ions of $^{53}$Cr isotope in concentration 0.03–0.05 ат.%. The optical echo-experiment is carried out in the backward regime on the wavelength 6934 Å in absence of magnetic field. The studied dependence of intensity of the stimulated photon echo on the time interval between the second and third pulses (under the fixed value of interval between first and second pulses) has the characteristic “break”, testifying to participation in forming an echo of a signal of hyperfine sublevels of the ground state.