INTENSITY-DEPENDENT PHOTON-ECHO RELAXATION IN RARE-EARTH-DOPED CRYSTALS

Photon-echo-relaxation measurements made on the H43-3P0 transition of 0.01 at. % Pr3+:YAG (where YAG represents yttrium aluminum garnet), H43-1D2 transition in 0.1 at. % Pr3+:YAlO3, and F07-5D0 transition in 0.25 at. % Eu3+:YAlO3 show that the photon-echo relaxation rate increases when the intensities of the excitation pulses are increased. Although a part of the relaxation-rate increase in Pr3+:YAG may be attributed to an instantaneous spectral diffusion (ISD) in which the presence of excited neighboring Pr3+ ions change the local field and the absorption frequency of the rare-earth ions, our data deviate significantly from the ISD-model predictions. An additional intensity-dependent relaxation mechanism is required to explain the results. © 1990 The American Physical Society.