Optical Echo-Spectroscopy of Highly Doped $\mathrm{YAG}:\mathrm{TM}$ Crystal

Two-pulse, stimulated and accumulated photon echoes are investigated for the first time in a highly doped crystal $\mathrm{Tm}:\mathrm{YAG}$ containing 10 at.% $\mathrm{Tm}^{3+}$. The decay curves of the two-pulse and stimulated photon echoes generated at 793,15 nm on the transition $^3\mathrm H_6(1)-^3\mathrm H_4(1)$ of the impurity ions are measured in the absence of an applied magnetic field. Parameters describing the energy and phase relaxation are determined. The dependence of the accumulated photon echo intensity on the number of excitation pulse pairs is investigated.