Photon echoes in an amplifying rare-earth-ion-doped crystal

We report what we believe is the first experimental demonstration of photon echoes in an amplifying rareearth-ion-doped crystal. Population inversion is achieved by optical pumping, which yields high-power photon echoes, with an energy gain of as much as a factor of 5. Effects of the pump on the photon echo process highlight the advantages of an amplifying crystal. New questions concerning the optical dephasing mechanisms in Er³⁺:YSO have arisen.