PHOTON-ECHO ATTENUATION BY DYNAMICAL PROCESSES IN RARE-EARTH-ION-DOPED CRYSTALS

We study the photon-echo attenuation by various dynamical processes in rare-earth-ion-doped crystals. The experimental investigations concen trate on a Pr3+:EU3+:Nd3+ codoped Y2SiO5 crystal at low temperatures. Two-pulse photon-echo intensities are measured as a function of the pu lse intensities when either the Pr3+ Or the EU3+ ions are excited. For the quantitative interpretation we consider primarily excitation-indu ced frequency shifts (EFS) by diagonal and off-diagonal interactions a nd show that for the systems under consideration EFS are dominated by diagonal interactions. The observed echo attenuation by EFS is compare d with the predictions calculated from independent Stark-field measure ments and reasonable agreement is obtained. The broadening by spin-ion interactions, by nonequilibrium phonons and the dependence of the ech o attenuation on the frequency position in the inhomogeneously broaden ed band are further investigated.