Influence of excited-statePr3+on the relaxation of thePr3+:YAlO33H4−1D2transition

Abstract

Two-pulse photon-echo measurements on the 0.1 at. % ${\mathrm{Pr}}^{3+}$:${\mathrm{YAlO}}_3$ ${}_{}{}^3{}_{}{}^{}$ ${\mathit{H}}_4$ ${\mathrm{-}}^1$ ${\mathit{D}}_2$ transition suggest that the relaxation time depends on the density of excited states created by the excitation pulses. The dependence of the relaxation time on the intensity of each excitation pulse shows that our results are inconsistent with instantaneous spectral diffusion, a model often invoked in this type of experiment, where excited states created by the second pulse chiefly influence the relaxation time. A homogeneous linewidth contribution, noted in previous work as being of unknown origin, is eliminated at low excitation fluences.