LASER-INDUCED INSTANTANEOUS SPECTRAL DIFFUSION IN TB-3+ COMPOUNDS AS OBSERVED IN PHOTON-ECHO EXPERIMENTS

We have observed a significant instantaneous spectral diffusion phenomenon in photon-echo experiments on Tb3+:LiYF4. This laser-induced effect makes observed optical dephasing rates intensity dependent and can also contribute a frequency dependence to the measured rates. A change in the magnetic dipole-dipole interaction between Tb3+ echo ions and surrounding Tb3+ ions occurs when surrounding ions are excited. This causes an instantaneous shift in the optical frequency of the echo ion that lasts for T11 msec. Frequency shifts caused by the first excitation pulse have no effect on echo rephasing (T1T2), but those caused by the second pulse prevent proper echo rephasing. A summary is given of other ion-lattice and ion-ion interactions that can cause similar laser-induced effects in a wide variety of insulating compounds. There is potential for probing the nature of inhomogeneous broadening. © 1990 The American Physical Society.