SITE INTERFERENCE IN STARK-MODULATED PHOTON-ECHOES

We show that Stark-pulse-modulated photon echoes in an impurity-ion-do ped crystal are generally characterized by a complex oscillatory behav ior with two or more frequency components which results from the inter ference of the static dipole moment differences of ions located at ine quivalent sites. We analyze this phenomenon using group theory and pre sent experimental evidence for a Pr3+ and Eu3+-codoped YAlO3 and a Pr3 +-doped Y2SiO5 crystal. It is demonstrated that the orientations of th e dipole moments and of the crystal axes can be determined with subdeg ree accuracy.